EXERCISE

[nicholson]

After years I still have not succeeded in getting my BMI below 21.  I have been aiming at 20.0.

 

I do get a fair amount of exercise, intentionally only once a week.  But the following podcast, apparently from a highly authoritative source, suggests a possible new way to solve the problem.  Of course, I understand that this is neither CR, nor ON.  And that the evidence shows that exercise has minimal benefit for health, or for losing weight, compared with that from restricting caloric intake.  Nevertheless, it would be nice to get down to 20.0 and even if one does not decide to adopt the advice offered here, the information appears of appreciable significance anyway.  I just may experiment with it.

  

SNR #95: Dr. James Levine – Physiological & Psychological Effects of Chronic Sitting & Low NEAT | Sigma Nutrition

  

 

 

 

 

 

 

 

SNR #95: Dr. James Levine – Physiological & Psychologica...

Episode 95:Dr. James Levine from the Mayo Clinic is on the show to discuss the effect of chronic sitting on the risk of blood sugar dysregulation, fat gain, obe

 

View on sigmanutrition.com

Preview by Yahoo

 

Rodney.

[Dean Pomerleau]

Rodney,

 

Can you summarize what the Dr. Levine is advocating relative to exercise, so what we don't all have to listen to the entire 46 minute interview, or at least we can get a feeling for what it is about so we can judge whether to listen or not?

 

Thanks!

 

--Dean

[sirtuin]

Very interesting podcast -- worth the full listen, imo.  The gist seems to be "humans aren't meant to sit around all day.  If you can find ways to get up and move instead of sit, you're going to look and feel better with improvements in health / mood / productivity."  Now, my wheels are spinning on Treadmill Desks vs Standing Desks vs Desk Cycles.

 

I work in web dev, where I spend upwards of full days sitting.  I somewhat balance this out by doing heavy resistance exercise and aerobic exercise through the week (plus housework / cooking / walking around).  But, there's a ton of sit-time.

 

I wonder what the safest / healthiest replacement for my seated workstation might be.  My thoughts are that if I go with a treadmill desk or desk cycle there might be unnecessary RSI on the hips / knees depending on the ergonomics (and I'm going to need to eat more food -- my BMI is already dipping slightly under 20 and I don't want to lose any muscle mass with unnecessary calorie burning.)  I've read a standing desk might be hard on the body.  I wonder if there's any sort of off-gasing concerns with putting a big treadmill desk in the office and running that motor / belt for hours daily.  Hmmm.

[Dean Pomerleau]

Having tried all three (standing desk, treadmill desk and desk cycle) I'm still fondest of my desk cycle. Plus its passive, so there is no running motor or electricity use.

 

--Dean

[nicholson]

In answer to your question Dean, from memory 24 hours after listening to it, the quickest simplest answer seems to be the following:

 

Whatever it is you do most of the day, if you can find a way to do it standing up instead of sitting down, you will burn an extra 350 calories a day.

 

[That, of course, represents 36.5 pounds of body weight per year!]

 

And I only need to lose ten to get to my targeted BMI of 20.0.

 

Rodney.

[Dean Pomerleau]

[Admin Note: I created a new thread on The Health Risks of Ozone for the posts about ozone that previously resided on this thread. Please see that thread to follow that discussion. -Dean]

[Dean Pomerleau]

Jogging & Health/Mortality

 

Here is the full text of a really thorough meta-analysis [1] on the pros and cons of running for various health and mortality outcomes. It basically confirms previous findings that it doesn't take too much running to max out the benefits. And further, too much or too strenuous running appears to be deleterious to health / longevity, largely as a result of excessive stress to the cardiovascular system.

 

Here are a couple of the sexier and more informative graphs from the paper, illustrating the U-shaped (or more aptly, flipped J-shaped) relationship between jogging duration/distance/speed and health/mortality.

 

As you can see from this forest plot, there are wide error bars on the risk associated with strenuous jogging, largely as a result of how few people were in that category. But the trend appears pretty clear - it doesn't take much jogging to max out the benefits, and more doesn't appear to be better.

 

 

The "sweet spot" for running along various metrics appears to be fairly wide, i.e. 1 - 3 h/wk, <6 - 19 mi/week, and 1-5 times/wk, and anything less than 7.5mph.

 

 

 

 

Here is a diagram of the mechanisms by which it appears too much running can lead to negative cardiovascular consequences:

 

 

Here is a bar graph of the impact of various amounts of running on all-cause and cause-specific mortality. As you can see, the increase in all-cause mortality from those who run the most (compared to light runners) appears to be a result of heart disease, stroke or other cardiovascular problems:

 

 

 

 

So overall, it looks like the evidence is reasonably strong that one should go easy on the jogging to maximize health and longevity benefits.

 

--Dean

 

-----------

[1] Mayo Clin Proc. 2015 Nov;90(11):1541-52. doi: 10.1016/j.mayocp.2015.08.001. Epub 

2015 Sep 8.

 

Effects of Running on Chronic Diseases and Cardiovascular and All-Cause

Mortality.

 

Lavie CJ(1), Lee DC(2), Sui X(3), Arena R(4), O'Keefe JH(5), Church TS(6), Milani

RV(7), Blair SN(3).

 

Considerable evidence has established the link between high levels of physical

activity (PA) and all-cause and cardiovascular disease (CVD)-specific mortality. 

Running is a popular form of vigorous PA that has been associated with better

overall survival, but there is debate about the dose-response relationship

between running and CVD and all-cause survival. In this review, we specifically

reviewed studies published in PubMed since 2000 that included at least 500

runners and 5-year follow-up so as to analyze the relationship between vigorous

aerobic PA, specifically running, and major health consequences, especially CVD

and all-cause mortality. We also made recommendations on the optimal dose of

running associated with protection against CVD and premature mortality, as well

as briefly discuss the potential cardiotoxicity of a high dose of aerobic

exercise, including running (eg, marathons).

 

Copyright © 2015 Mayo Foundation for Medical Education and Research. Published by

Elsevier Inc. All rights reserved.

 

PMID: 26362561

[nicholson]

Thanks Dean:

 

Very interesting data.  I cannot resist pointing out (!) that the chart of the hazard ratios of all cause mortality shows that the best FREQUENCY (granted, not by a huge margin, but nevertheless the best) for physical activity is among those exercising once or twice a week.

 

So, as usual, the perpetrators of the 'conventional wisdom', who keep telling us we must exercise "at least five days a week", are 'mistaken'.  More than two days a week is a waste of time, energy, psychological resources, etc..

 

The simple explanation is that in order for the body to gain the greatest benefit from a bout of exercise - which entails breakdown of cells in the organs involved - it needs three days to rebuild so it can again gain the greatest benefit from the next bout.  Continuous breakdown, day after day, without the opportunity to rebuild, provides no further benefit.  Just wasted effort and processing of additional calories. 

 

For people my age, a frequency of once a week is likely plenty in my judgment, so long as the quantity of exercise is fairly substantial.

 

Rodney.

 

=================

 

"The unverified conventional wisdom is almost invariably mistaken."

[Michael R]

Note that this is not a meta-analysis, but a review of previous studies on running and health outcomes that inform these questions. Those two quantitative figures are each taken from different, individual studies (see the legends for both): the forest plot is taken from joggers in the Copenhagen City Heart Study (PMID 25660917), and the line graph is from one study in a subset from the Aerobics Center Longitudinal Study (PMID 25082581). I know of no meta-analysis that breaks down time, frequency, and/or intensity — just either measured (rather than reported) cardiorespiratory fitness, or self-reported MET-hours, aggregating intensity and total time.

[Dean Pomerleau]

For anyone interested in the effects of various levels of exercise, see this post by Rodney from a while back on the "CR and Exercise" thread.

 

It cites [1] and [2]. Study [1] was particularly interesting. It followed over 600,000 people for an average of 14+ years to determine how the amount of (self-reported) exercise they did impacted their all-cause mortality.

 

They found that 3-5 times the 7.5 MET-hours/wk minimum exercise recommendation (i.e. 22.5-37.5 MET-hours/wk) was a threshold above which more exercise didn't provide further benefits. This 22.5-37.5 MET-hours/wk is equivalent to about 45-60 min of brisk walking (4mph) per day, and resulted in a nearly 40% reduction in mortality relative to people who reported no leisure time physical activity. They found no increase in mortality among people who engaged in 10+ times the 7.5 MET-hours/wk recommendation, which is the equivalent of 2 hours or more of brisk walking per day. But at the same time, the additional exercise didn't provide any additional mortality reduction benefits relative to 22.5-37.5 MET-Hours/wk.

 

--Dean

 

--------

[1] Leisure Time Physical Activity and Mortality: A Detailed Pooled Analysis of

the Dose-Response Relationship.
Arem H, Moore SC, Patel A, Hartge P, Berrington de Gonzalez A, Visvanathan
K, Campbell PT, Freedman M, Weiderpass E, Adami HO, Linet MS, Lee IM,
Matthews CE.
JAMA Intern Med. 2015 Apr 6. doi: 10.1001/jamainternmed.2015.

0533. [Epub
ahead of print]
PMID:25844730

Abstract

Importance: The 2008 Physical Activity Guidelines for Americans recommended
a minimum of 75 vigorous-intensity or 150 moderate-intensity minutes per
week (7.5 metabolic-equivalent hours per week) of aerobic activity for
substantial health benefit and suggested additional benefits by doing more
than double this amount. However, the upper limit of longevity benefit or
possible harm with more physical activity is unclear.

Objective: To quantify the dose-response association between leisure time
physical activity and mortality and define the upper limit of benefit or
harm associated with increased levels of physical activity.

Design, Setting, and Participants: We pooled data from 6 studies in the
National Cancer Institute Cohort Consortium (baseline 1992-2003).
Population-based prospective cohorts in the United States and Europe with
self-reported physical activity were analyzed in 2014. A total of 661 137
men and women (median age, 62 years; range, 21-98 years) and 116 686 deaths
were included. We used Cox proportional hazards regression with cohort
stratification to generate multivariable-adjusted hazard ratios (HRs) and
95% CIs. Median follow-up time was 14.2 years.

Exposures: Leisure time moderate- to vigorous-intensity physical activity.

Main Outcomes and Measures: The upper limit of mortality benefit from high
levels of leisure time physical activity.

Results: Compared with individuals reporting no leisure time physical
activity, we observed a 20% lower mortality risk among those performing less
than the recommended minimum of 7.5 metabolic-equivalent hours per week (HR,
0.80 [95% CI, 0.78-0.82]), a 31% lower risk at 1 to 2 times the recommended
minimum (HR, 0.69 [95% CI, 0.67-0.70]), and a 37% lower risk at 2 to 3 times
the minimum (HR, 0.63 [95% CI, 0.62-0.65]). An upper threshold for mortality
benefit occurred at 3 to 5 times the physical activity recommendation (HR,
0.61 [95% CI, 0.59-0.62]); however, compared with the recommended minimum,
the additional benefit was modest (31% vs 39%). There was no evidence of
harm at 10 or more times the recommended minimum (HR, 0.69 [95% CI,
0.59-0.78]). A similar dose-response relationship was observed for mortality
due to cardiovascular disease and to cancer.

Conclusions and Relevance: Meeting the 2008 Physical Activity Guidelines for
Americans minimum by either moderate- or vigorous-intensity activities was
associated with nearly the maximum longevity benefit. We observed a benefit
threshold at approximately 3 to 5 times the recommended leisure time
physical activity minimum and no excess risk at 10 or more times the
minimum. In regard to mortality, health care professionals should encourage
inactive adults to perform leisure time physical activity and do not need to
discourage adults who already participate in high-activity levels.

----------

[2] Effect of Moderate to Vigorous Physical Activity on All-Cause Mortality in
Middle-aged and Older Australians.
Gebel K, Ding D, Chey T, Stamatakis E, Brown WJ, Bauman AE.
JAMA Intern Med. 2015 Apr 6. doi: 10.1001/jamainternmed.2015.0541. [Epub
ahead of print]
PMID:25844882

Abstract

Importance: Few studies have examined how different proportions of moderate
and vigorous physical activity affect health outcomes.

Objective: To examine whether the proportion of total moderate to vigorous
activity (MVPA) that is achieved through vigorous activity is associated
with all-cause mortality independently of the total amount of MVPA.

Design, Setting, and Participants: We performed a prospective cohort study
with activity data linked to all-cause mortality data from February 1, 2006,
through June 15, 2014, in 204 542 adults aged 45 through 75 years from the
45 and Up population-based cohort study from New South Wales, Australia
(mean [sD] follow-up, 6.52 [1.23] years). Associations between different
contributions of vigorous activity to total MVPA and mortality were examined
using Cox proportional hazards models, adjusted for total MVPA and
sociodemographic and health covariates.

Exposures: Different proportions of total MVPA as vigorous activity.
Physical activity was measured with the Active Australia Survey.

Main Outcomes and Measures: All-cause mortality during the follow-up period.

Results: During 1 444 927 person-years of follow-up, 7435 deaths were
registered. Compared with those who reported no MVPA (crude death rate,
8.34%), the adjusted hazard ratios for all-cause mortality were 0.66 (95%
CI, 0.61-0.71; crude death rate, 4.81%), 0.53 (95% CI, 0.48-0.57; crude
death rate, 3.17%), and 0.46 (95% CI, 0.43-0.49; crude death rate, 2.64%)
for reporting 10 through 149, 150 through 299, and 300 min/wk or more of
activity, respectively. Among those who reported any MVPA, the proportion of
vigorous activity revealed an inverse dose-response relationship with
all-cause mortality: compared with those reporting no vigorous activity
(crude death rate, 3.84%) the fully adjusted hazard ratio was 0.91 (95% CI,
0.84-0.98; crude death rate, 2.35%) in those who reported some vigorous
activity (but <30% of total activity) and 0.87 (95% CI, 0.81-0.93; crude
death rate, 2.08%) among those who reported 30% or more of activity as
vigorous. These associations were consistent in men and women, across
categories of body mass index and volume of MVPA, and in those with and
without existing cardiovascular disease or diabetes mellitus.

Conclusions and Relevance: Among people reporting any activity, there was an
inverse dose-response relationship between proportion of vigorous activity
and mortality. Our findings suggest that vigorous activities should be
endorsed in clinical and public health activity guidelines to maximize the
population benefits of physical activity.

[nicholson]

Thanks Dean:

 

In the case of PMID:25844882 do we know what their criteria were for distinguishing between 'moderate' and 'vigorous'? 

 

I am wondering if 'vigorous' was in effect defined in terms of number of calories expended per minute (which seems most likely).  Or whether it was total calories expended in a week.

 

In other words, for the exercise to be defined as 'vigorous' did they have to be running 100 metres in 15 seconds or less - or a mile in six minutes or less?  Or was a substantial weekly quantity also classified as vigorous?

 

Do you see my point?  If it was the former then maybe we should all be doing some sprint activity, which I presently do not.

 

Rodney.

 

===============

 

"The unverified conventional wisdom is almost invariably mistaken."

[Dean Pomerleau]

Rodney,

 

 

In the case of PMID:25844882 do we know what their criteria were for distinguishing between 'moderate' and 'vigorous'? 

 

Here is the authors description from the full text of PMID 25844882 (via sci-hub.io) about how they categorized "moderate" and "vigorous" exercise:

 

Self-reported data were used from the baseline questionnaire

(http://www.45andUp.org.au). Moderate to vigorous

physical activity was measured with items from the Active Australia

Survey,33 which asks participants about sessions (bouts

of at least 10 minutes) and duration of walking, moderate, and

vigorous activity in the past week. In the questionnaire, vigorous

activity is defined as activity “that made you breathe

harder or puff and pant, like jogging, cycling, aerobics, competitive

tennis, but not household chores or gardening.” For

moderate activity examples “like gentle swimming, social tennis,

vigorous gardening or work around the house” are provided.

 

I am wondering if 'vigorous' was in effect defined in terms of number of calories expended per minute (which seems most likely).  Or whether it was total calories expended in a week.

 

No calories / min involved. They simply asked participants how many minutes per week they engaged in moderate or vigorous physical activities, examples of which are listed above. So as for your question about whether sprinting is as or more beneficial than jogging - this study in no way addresses it. In fact, their requirement that the bouts of physical activity be of at least 10 minutes pretty much precludes some of the most intense HIIT (High Intensity Interval Training) workouts as I understand them.

 

It simply found that by these types of self-reports, people who engaged in more moderate or vigorous physical exercise had a lot lower risk of all-cause mortality, in a monotonically increasing fashion (i.e. the more exercise the better). And those who reported the most vigorous exercise (i.e. >30% of total exercise) saw the most benefits.

 

--Dean

[Dean Pomerleau]

I couple posts ago in this thread, Rodney made the astute observation that self-reported exercise, and without more information on the degree of vigor of the exercise people really engage in, leaves us guessing to a large degree about the optimal dose and intensity of exercise for health & longevity. So it was with interest that I read two studies posted by Al Pater (thanks as usual Al!) over the holiday about various metrics of exercise / fitness and how they relate to all-cause mortality.

 

In the first study [1], researchers measured daily step count of with a fitness tracker of 2600 study participants (average age 59), and then followed them for an average of 7.5 years (excluding the first 2 years) to see how many people died as a function of daily step count.

 

The researchers found a linear inverse relationship between daily steps and mortality. Those in the highest quintile of daily steps taken (13,500 - 39,000, almost as many as I take!) had a dramatically lower death rate than those in the lower quintiles. Here is the data, which requires a bit of qualification (see below):

 

 

The "Observed" column means the observed number of deaths. "Expected" means expected number of deaths based on the increased average age of the more sedentary study participants. So if we compare the Observed vs. Expected number of deaths in the first quintile (0 - 5,500 steps) we see there were twice as many deaths observed than was expected. Conversely, in the fifth quintile, we see there were only about 1/3rd as many deaths as expected (i.e. predicted) based on the subjects age. So quite a dramatic improvement in death rate with increasing number of steps taken, all the way up to a quite large number of daily steps (13,500 - 39,000). The authors note specifically the relationship looks linear (i.e. no threshold above which more steps isn't any better):

 

The 5 category model (Table 2) or fractional polynomial

models did not fit the data better than a linear model, indicating a linear pattern was evident

between increasing baseline daily steps and subsequent mortality in the adjusted analysis.

 

This results seems to explicitly point against Rodney's hypothesis that there is a threshold above which more exercise isn't better, and in fact may be worse than infrequent exercise, as expressed in this statement of his:

 

So, as usual, the perpetrators of the 'conventional wisdom', who keep telling us we must exercise "at least five days a week", are 'mistaken'.  More than two days a week is a waste of time, energy, psychological resources, etc..

 

They also observed a dramatically lower risk of death among subjects who increased their daily step count, after controlling for other factors. So its never to late to start walking or other exercise!

 

In the second study [2] was a meta-analysis of the relationship between resting heart rate (RHR) and all-cause mortality. Researchers looked at 46 studies including 1.25 million subjects. They found an almost 10% increase in mortality for every 10 beat/min increase in  RHR. Further:

 

 Compared with 45  beats/min, the risk of all-cause mortality

increased significantly with increasing

resting heart rate in a linear relation, but a

significantly increased risk of cardiovascular

mortality was observed at 90 beats/min.

 

and:

Compared with the lowest

category , patients with a resting heart rate of

60–80  beats/min had a relative risk of 1.12

(95% CI 1.07–1.17) for all-cause mortality and

1.08 (95% CI 0.99–1.17) for cardiovascular

mortality, and those with a resting heart rate

of greater than  80  beats/min had a relative

risk of 1.45 (95% CI 1.34–1.57) for all-cause

mortality and 1.33 (95% CI 1.19–1.47) for cardiovascular

mortality.

 

While this result doesn't directly counter Rodney's contention about frequent exercise being worse than infrequent, it does suggest that being in better cardiovascular shape (as measured by resting heart rate), is linearly associated with better survival.

 

I think it pretty likely that to get one's resting heart rate down to the range suggested to be optimal by these researchers (~45 beats/min), requires frequent aerobic exercise, although CR folks are know to have lower heart rate regardless of exercise. Rodney, what's your resting heart rate while practicing CR and infrequently exercising?

 

--Dean

 

-------------

[1]  Objectively Measured Daily Steps and Subsequent Long Term All-Cause Mortality: The Tasped Prospective Cohort Study.

Dwyer T, Pezic A, Sun C, Cochrane J, Venn A, Srikanth V, Jones G, Shook R, Sui X, Ortaglia A, Blair S, Ponsonby AL.

PLoS One. 2015 Nov 4;10(11):e0141274. doi: 10.1371/journal.pone.0141274. eCollection 2015.

PMID: 26536618 Free PMC Article

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4633039/

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4633039/pdf/pone.0141274.pdf

 

Abstract

 

BACKGROUND:

 

Self-reported physical activity has been inversely associated with mortality but the effect of objectively measured step activity on mortality has never been evaluated. The objective is to determine the prospective association of daily step activity on mortality among free-living adults.

 

METHODS AND FINDINGS:

 

Cohort study of free-living adults residing in Tasmania, Australia between 2000 and 2005 who participated in one of three cohort studies (n = 2 576 total participants). Daily step activity by pedometer at baseline at a mean of 58.8 years of age, and for a subset, repeated monitoring was available 3.7 (SD 1.3) years later (n = 1 679). All-cause mortality (n = 219 deaths) was ascertained by record-linkage to the Australian National Death Index; 90% of participants were followed-up over ten years, until June 2011. Higher daily step count at baseline was linearly associated with lower all-cause mortality (adjusted hazard ratio AHR, 0.94; 95% CI, 0.90 to 0.98 per 1 000 steps; P = 0.004). Risk was altered little by removing deaths occurring in the first two years. Increasing baseline daily steps from sedentary to 10 000 steps a day was associated with a 46% (95% CI, 18% to 65%; P = 0.004) lower risk of mortality in the decade of follow-up. In addition, those who increased their daily steps over the monitoring period had a substantial reduction in mortality risk, after adjusting for baseline daily step count (AHR, 0.39; 95% CI, 0.22 to 0.72; P = 0.002), or other factors (AHR, 0.38; 95% CI, 0.21-0.70; P = 0.002).

 

CONCLUSIONS:

 

Higher daily step count was linearly associated with subsequent long term mortality among free living adults. These data are the first to quantify mortality reductions using an objective measure of physical activity in a free living population. They strongly underscore the importance of physical inactivity as a major public health problem.

 

-----------

[2] Resting heart rate and all-cause and cardiovascular mortality in the general population: a meta-analysis.

Zhang D, Shen X, Qi X.

CMAJ. 2015 Nov 23. pii: cmaj.150535. [Epub ahead of print]

PMID: 26598376

http://www.cmaj.ca/content/early/2015/11/23/cmaj.150535.full.pdf+html?sid=5a409e25-3f7a-4d5f-a3bb-8456e618f296

 

Abstract

 

BACKGROUND:

 

Data on resting heart rate and risk of all-cause and cardiovascular mortality are inconsistent; the magnitude of associations between resting heart rate and risk of all-cause and cardiovascular mortality varies across studies. We performed a meta-analysis of prospective cohort studies to quantitatively evaluate the associations in the general population.

 

METHODS:

 

We searched PubMed, Embase and MEDLINE from inception to Jan. 1, 2015. We used a random-effects model to combine study-specific relative risks and 95% confidence intervals (CIs). We used restricted cubic spline functions to assess the dose-response relation.

 

RESULTS:

 

A total of 46 studies were included in the meta-analysis, involving 1 246 203 patients and 78 349 deaths for all-cause mortality, and 848 320 patients and 25 800 deaths for cardiovascular mortality. The relative risk with 10 beats/min increment of resting heart rate was 1.09 (95% CI 1.07-1.12) for all-cause mortality and 1.08 (95% CI 1.06-1.10) for cardiovascular mortality. Compared with the lowest category, patients with a resting heart rate of 60-80 beats/min had a relative risk of 1.12 (95% CI 1.07-1.17) for all-cause mortality and 1.08 (95% CI 0.99-1.17) for cardiovascular mortality, and those with a resting heart rate of greater than 80 beats/min had a relative risk of 1.45 (95% CI 1.34-1.57) for all-cause mortality and 1.33 (95% CI 1.19-1.47) for cardiovascular mortality. Overall, the results did not differ after adjustment for traditional risk factors for cardiovascular disease. Compared with 45 beats/min, the risk of all-cause mortality increased significantly with increasing resting heart rate in a linear relation, but a significantly increased risk of cardiovascular mortality was observed at 90 beats/min. Substantial heterogeneity and publication bias were detected.

 

INTERPRETATION:

 

Higher resting heart rate was independently associated with increased risks of all-cause and cardiovascular mortality. This indicates that resting heart rate is a predictor of all-cause and cardiovascular mortality in the general population.

[nicholson]

Hi Dean:

 

You ask about resting heart rate  .......  I find my lowest resting heart rate - rather surprisingly, to me - tends to occur if/when I am in a resting state in mid-morning.  On rare occasions, usually late in the evening, it can be near 50.  But in recent months it has ranged between 42 and 47 the vast majority of the time.  On very rare occasions, including mid-morning yesterday, I see it slightly under 40.  On one amusing occasion this happened when I went to get the vaccination that protects against shingles, around 10:30 am. one morning.  After you get the shot you are required to stay around for 30 minutes in case you experience an allergic reaction.  So I suggested I get on the blood pressure machine to check my BP.  When the nurse came back and saw the machine saying my pulse rate was 39 she said nothing, turned right around and returned with reinforcements!  It will be interesting to see what happens if I do eventually get my BMI down to 20.0.  

 

Rodney.

 

===========

 

"The unverified conventional wisdom is almost invariably mistaken."

[Dean Pomerleau]

Rodney,

 

Quite impressive resting heart rate numbers - congratulations! I wonder how common it is for CR folks to have the sort of very low resting heart rate numbers that you and I enjoy.

 

Anyone else have RHR numbers they'd care to share?

 

--Dean

[sirtuin]

Rodney,

 

Quite impressive resting heart rate numbers - congratulations! I wonder how common it is for CR folks to have the sort of very low resting heart rate numbers that you and I enjoy.

 

Anyone else have RHR numbers they'd care to share?

 

--Dean

If I wear a heart monitor during sleep, I'm under 40.

 

Here's mine, measuring after getting up on the computer and walking around for a bit.  It actually felt a little bit faster than usual.  If I measured while laying down in bed in the early morning, I'm probably down in the lower 40's to high 30's.

 

 

Looking at blood pressure readings from my Omron device, it seems as though I climb up into the 50's once I've had a very large breakfast, 2-3 cups of strong black coffee, exercise (lately, HIIT/Resistance/Aerobic), and strap on a BP monitor while sitting up at the kitchen.  I find this can be attenuated and keep me in the low 40's even after coffee/activity by eating lower calories and smaller meals (closer to 1800-1900kcal), but lately I'm up closer to 2200kcal and more active with an eye on RHR+BP for CR purposes.

 

 

Now, what's interesting is my doctor usually tries to prescribe me Propranolol to slow my heart down and lower my blood pressure, as my heart rate and BP are often increased at the office (I have a bit of a white coat syndrome.)  I took it for a week or so by prescription, but felt very dizzy and was getting down into the high 30's on very small dosages.  It was kind of cool going for a very hard run and not seeing much of a heart rate increase, but I soon stopped taking it.  Looking my doctor up on https://projects.propublica.org/docdollars, they have received tens of thousands of dollars, with "Innopran XL" topping the list for drug fund contributions -- aka, propranolol.

[nicholson]

Hi Sirtuin:

 

Interesting data.  Can you please share your current BMI with us?

 

Rodney.

 

=========

 

"In my experience the unverified conventional wisdom is almost invariably mistaken."

[sirtuin]

Hi Sirtuin:

 

Interesting data.  Can you please share your current BMI with us?

 

Rodney.

 

=========

 

"In my experience the unverified conventional wisdom is almost invariably mistaken."

Right now, I'm up around 138lb at 5'9".  This puts me at a BMI around 20.4, although I spent a good amount of time doing heavy resistance exercise and carbohydrate cycling with a higher hypercaloric protein intake in the past (ie. "leangains"), where I have fairly low body fat / minimal abdominal fat at this BMI.  I have a bit of an inner conflict between CR / Aerobic exercise / Lower protein intakes / lower carbohydrate intakes and Anabolic Resistance Exercise / Higher protein & carbohydrate intakes.

 

Recent lab work put me at an LDL-C of 63 mg/dL, HDL-C of 58 mg/dL.  Triglycerides of 56 mg/dL.  Total Cholesterol of 132 mg/dL.  LDL-P of 908 nmol/L.  Small LDL-P < 90 nmol/L, and LDL Size of 21.2 nm.  A1C of 5.3%.   I'll be curious to recheck this sometime in the near future with slight dietary modification.  (I'm suspecting my next labs should show higher HDL-C, lower Trigs, lower A1C, with unknown effects on LDL-C/LDL-P.)

[Dean Pomerleau]

This study [1] from 2013 would seem to shed some light on the relatively health advantages and disadvantages of shorter, more vigorous bouts of exercise vs. longer, less-intense exercise. They had 18 young (~21 yo), slim (BMI ~22.6) and healthy subjects follow each of three different exercise regimes for 4 days each:

 

Participants were instructed to sit 14 hr/day (sitting regime); to sit 13 hr/day 

and to substitute 1 hr of sitting with vigorous exercise 1 hr (exercise regime); 

to substitute 6 hrs sitting with 4 hr walking and 2 hr standing (minimal

intensity physical activity (PA) regime). The sitting and exercise regime had

comparable numbers of sitting hours; compared to the exercise regime, the minimal

intensity PA regime had a higher estimated daily energy expenditure (238kcal/day)

[corrected].

 

The exercise regime was 1 hour of cycling on a stationary bike with their heart rate elevated 52 BPM higher than their baseline - so it was pretty vigorous. The average daily calorie expenditures for the three conditions were: sedentary = 1934, exercise = 2248, PA = 2486.

 

This was a crossover design, so each participating was part of all three groups over time (at least 10 day washout period between). The subjects were asked to maintain their normal diet and lifestyle both between and during the 4-day trials, but not to do any other exercise. Their diets were not controlled or monitored, but there activity / exercise was tracked during each 4-day test using an activity tracker.

 

At the end of each study 4-day period, they underwent a fasting blood test and an oral glucose tolerance test (OGTT).

 

Results? They found that the minimal intensity physical activity (PA) group had better insulin sensitivity relative to both the control group and the exercise group - in other words, they cleared the standardized dose of glucose with less insulin during the OGTT.  Here are the graphs of both the insulin levels over time and insulin area under the curve during the OGTT for the three conditions:

 

Note the vigorous exercise condition in red appeared slightly (but not significantly) worse than sitting.

 

Several of the standard blood tests favored the PA group as well, including:

 

Triglycerides, non-HDL cholesterol and apolipoprotein B plasma levels improved

significantly in the minimal intensity PA regime compared to sitting and showed

non-significant trends for improvement compared to exercise.

 

From the full text, LDL-cholesterol and fasting insulin were also lowest in the PA group, but not quite significantly so.

 

So at least in these young & thin individuals, it appeared longer and gentler exercise (i.e. walking 4h and standing 2h per day) beat shorter, more intense workouts (biking pretty hard for an hour per day) when it came to several important markers of health and (possibly) longevity.

 

Of course some might say that even one hour of relatively intense aerobic exercise is too much, and subjects would have been better off had the exercise condition been a short (5-15min) but very intense HITT workout instead. This meta-analysis [4] of studies in mostly obese and/or Type II diabetics of HIIT vs. continuous exercise vs. sedentary controls found insulin sensitivity was significantly better after HIIT training compared to the sedentary control condition, and marginally better after HIIT than after less intense continuous training, generally similar to the exercise condition in the current study. Such studies don't universally show benefits of HIIT relative to continuous moderate exercise, like this very recent one that found no difference between the two type of exercise for 12 weeks on any markers of health, including insulin in obese women. So while there might be some truth to the idea that HIIT is better than an hour of continuous exercise per day for some health markers like insulin sensitivity, the jury is still out it would seem.

 

Alternatively, some might say CR in the sedentary group would have potentiated insulin to the degree observed in the PA group. Unfortunately this study didn't address this issue, but Luigi's study comparing we CR folks to similarly thin runners found we had comparable insulin sensitivity, although we (at least some of us) famously did worse on the OGTT [5].

 

More about the various mechanism by which exercise improves insulin sensitivity can be found in these studies [2][3], for anyone interested.

 

--Dean

 

----------

[1] PLoS One. 2013;8(2):e55542. doi: 10.1371/journal.pone.0055542. Epub 2013 Feb 13.

Minimal intensity physical activity (standing and walking) of longer duration
improves insulin action and plasma lipids more than shorter periods of moderate
to vigorous exercise (cycling) in sedentary subjects when energy expenditure is
comparable.

Duvivier BM(1), Schaper NC, Bremers MA, van Crombrugge G, Menheere PP, Kars M,
Savelberg HH.

Author information:
(1)Department of Internal Medicine, Maastricht University Medical Centre,
Maastricht, The Netherlands.

 

Free full text: http://www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0055542&representation=PDF

Erratum in
PLoS One. 2014;9(8):e105135.

BACKGROUND: Epidemiological studies suggest that excessive sitting time is
associated with increased health risk, independent of the performance of
exercise. We hypothesized that a daily bout of exercise cannot compensate the
negative effects of inactivity during the rest of the day on insulin sensitivity
and plasma lipids.
METHODOLOGY/PRINCIPAL FINDINGS: Eighteen healthy subjects, age 21±2 year, BMI
22.6±2.6 kgm(-2) followed randomly three physical activity regimes for four days.
Participants were instructed to sit 14 hr/day (sitting regime); to sit 13 hr/day
and to substitute 1 hr of sitting with vigorous exercise 1 hr (exercise regime);
to substitute 6 hrs sitting with 4 hr walking and 2 hr standing (minimal
intensity physical activity (PA) regime). The sitting and exercise regime had
comparable numbers of sitting hours; compared to the exercise regime, the minimal
intensity PA regime had a higher estimated daily energy expenditure (238kcal/day)
[corrected]. PA was assessed continuously by an activity monitor (ActivPAL) and a
diary. Measurements of insulin sensitivity (oral glucose tolerance test, OGTT)
and plasma lipids were performed in the fasting state, the morning after the 4
days of each regime. In the sitting regime, daily energy expenditure was about
500 kcal lower than in both other regimes. Area under the curve for insulin
during OGTT was significantly lower after the minimal intensity PA regime
compared to both sitting and exercise regimes 6727.3±4329.4 vs 7752.0±3014.4 and
8320.4±5383.7 mU•min/ml, respectively. Triglycerides, non-HDL cholesterol and
apolipoprotein B plasma levels improved significantly in the minimal intensity PA
regime compared to sitting and showed non-significant trends for improvement
compared to exercise.
CONCLUSIONS: One hour of daily physical exercise cannot compensate the negative
effects of inactivity on insulin level and plasma lipids if the rest of the day
is spent sitting. Reducing inactivity by increasing the time spent
walking/standing is more effective than one hour of physical exercise, when
energy expenditure is kept constant.

PMCID: PMC3572053
PMID: 23418444

 

------------

[2] Int J Sports Med. 2000 Jan;21(1):1-12.

 

Exercise and insulin sensitivity: a review.

 

Borghouts LB(1), Keizer HA.

 

Author information: 

(1)Department of Movement Sciences, Maastricht University, The Netherlands.

lars.borghouts@bw.unimaas.nl

 

Physical activity has a beneficial effect on insulin sensitivity in normal as

well as insulin resistant populations. A distinction should be made between the

acute effects of exercise and genuine training effects. Up to two hours after

exercise, glucose uptake is in part elevated due to insulin independent

mechanisms, probably involving a contraction-induced increase in the amount of

GLUT4 associated with the plasma membrane and T-tubules. However, a single bout

of exercise can increase insulin sensitivity for at least 16 h post exercise in

healthy as well as NIDDM subjects. Recent studies have accordingly shown that

acute exercise also enhances insulin stimulated GLUT4 translocation. Increases in

muscle GLUT4 protein content contribute to this effect, and in addition it has

been hypothesized that the depletion of muscle glycogen stores with exercise

plays a role herein. Physical training potentiates the effect of exercise on

insulin sensitivity through multiple adaptations in glucose transport and

metabolism. In addition, training may elicit favourable changes in lipid

metabolism and can bring about improvements in the regulation of hepatic glucose 

output, which is especially relevant to NIDDM. It is concluded that physical

training can be considered to play an important, if not essential role in the

treatment and prevention of insulin insensitivity.

 

PMID: 10683091

 

----------

[3] Diabetes. 2012 Oct;61(10):2472-8. Epub 2012 Jul 10.

 

High oxidative capacity due to chronic exercise training attenuates lipid-induced

insulin resistance.

 

Phielix E(1), Meex R, Ouwens DM, Sparks L, Hoeks J, Schaart G, Moonen-Kornips E, 

Hesselink MK, Schrauwen P.

 

Author information: 

(1)Department of Human Biology, NUTRIM School for Nutrition, Toxicology, and

Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.

 

Comment in

    Diabetes. 2012 Oct;61(10):2397-9.

 

Fat accumulation in skeletal muscle combined with low mitochondrial oxidative

capacity is associated with insulin resistance (IR). Endurance-trained athletes, 

characterized by a high oxidative capacity, have elevated intramyocellular

lipids, yet are highly insulin sensitive. We tested the hypothesis that a high

oxidative capacity could attenuate lipid-induced IR. Nine endurance-trained (age 

= 23.4 ± 0.9 years; BMI = 21.2 ± 0.6 kg/m(2)) and 10 untrained subjects (age =

21.9 ± 0.9 years; BMI = 22.8 ± 0.6 kg/m(2)) were included and underwent a clamp

with either infusion of glycerol or intralipid. Muscle biopsies were taken to

perform high-resolution respirometry and protein phosphorylation/expression.

Trained subjects had ~32% higher mitochondrial capacity and ~22% higher insulin

sensitivity (P < 0.05 for both). Lipid infusion reduced insulin-stimulated

glucose uptake by 63% in untrained subjects (P < 0.05), whereas this effect was

blunted in trained subjects (29%, P < 0.05). In untrained subjects, lipid

infusion reduced oxidative and nonoxidative glucose disposal (NOGD), whereas

trained subjects were completely protected against lipid-induced reduction in

NOGD, supported by dephosphorylation of glycogen synthase. We conclude that

chronic exercise training attenuates lipid-induced IR and specifically attenuates

the lipid-induced reduction in NOGD. Signaling data support the notion that high 

glucose uptake in trained subjects is maintained by shuttling glucose toward

storage as glycogen.

 

PMCID: PMC3447923

PMID: 22787138

 

-----------

[4] Obes Rev. 2015 Nov;16(11):942-61. doi: 10.1111/obr.12317.

 

The effects of high-intensity interval training on glucose regulation and insulin

resistance: a meta-analysis.

 

Jelleyman C(1,)(2), Yates T(1,)(2), O'Donovan G(1), Gray LJ(3), King JA(2,)(4),

Khunti K(1,)(5), Davies MJ(1,)(2).

 

Author information: 

(1)Diabetes Research Centre, University of Leicester, Leicester, UK. (2)NIHR

Leicester-Loughborough Diet, Lifestyle and Physical Activity Biomedical Research 

Unit, Leicester & Loughborough, UK. (3)Department of Health Sciences, University 

of Leicester, Leicester, UK. (4)School of Sport, Exercise and Health Sciences,

Loughborough University, Loughborough, UK. (5)NIHR Collaboration for Leadership

in Applied Health Research and Care - East Midlands (NIHR CLAHRC - EM),

Leicester, UK.

 

The aim of this meta-analysis was to quantify the effects of high-intensity

interval training (HIIT) on markers of glucose regulation and insulin resistance 

compared with control conditions (CON) or continuous training (CT). Databases

were searched for HIIT interventions based upon the inclusion criteria: training 

≥2 weeks, adult participants and outcome measurements that included insulin

resistance, fasting glucose, HbA1c or fasting insulin. Dual interventions and

participants with type 1 diabetes were excluded. Fifty studies were included.

There was a reduction in insulin resistance following HIIT compared with both CON

and CT (HIIT vs. CON: standardized mean difference [sMD] = -0.49, confidence

intervals [CIs] -0.87 to -0.12, P = 0.009; CT: SMD = -0.35, -0.68 to -0.02,

P = 0.036). Compared with CON, HbA1c decreased by 0.19% (-0.36 to -0.03,

P = 0.021) and body weight decreased by 1.3 kg (-1.9 to -0.7, P < 0.001). There

were no statistically significant differences between groups in other outcomes

overall. However, participants at risk of or with type 2 diabetes experienced

reductions in fasting glucose (-0.92 mmol L(-1) , -1.22 to -0.62, P < 0.001)

compared with CON. HIIT appears effective at improving metabolic health,

particularly in those at risk of or with type 2 diabetes. Larger randomized

controlled trials of longer duration than those included in this meta-analysis

are required to confirm these results.

 

© 2015 World Obesity.

 

PMID: 26481101

 

-------------

[5] Age (Dordr). 2010 Mar;32(1):97-108. doi: 10.1007/s11357-009-9118-z. Epub 2009 Nov

11.

 

Effects of long-term calorie restriction and endurance exercise on glucose

tolerance, insulin action, and adipokine production.

 

Fontana L(1), Klein S, Holloszy JO.

 

Free full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2829643/

 

Calorie restriction (CR) slows aging and is thought to improve insulin

sensitivity in laboratory animals. In contrast, decreased insulin signaling

and/or mild insulin resistance paradoxically extends maximal lifespan in various 

genetic animal models of longevity. Nothing is known regarding the long-term

effects of CR on glucose tolerance and insulin action in lean healthy humans. In 

this study we evaluated body composition, glucose, and insulin responses to an

oral glucose tolerance test and serum adipokines levels in 28 volunteers, who had

been eating a CR diet for an average of 6.9 +/- 5.5 years, (mean age 53.0 +/- 11 

years), in 28 age-, sex-, and body fat-matched endurance runners (EX), and 28

age- and sex-matched sedentary controls eating Western diets (WD). We found that 

the CR and EX volunteers were significantly leaner than the WD volunteers.

Insulin sensitivity, determined according to the HOMA-IR and the Matsuda and

DeFronzo insulin sensitivity indexes, was significantly higher in the CR and EX

groups than in the WD group (P = 0.001). Nonetheless, despite high serum

adiponectin and low inflammation, approximately 40% of CR individuals exhibited

an exaggerated hyperglycemic response to a glucose load. This impaired glucose

tolerance is associated with lower circulating levels of IGF-1, total

testosterone, and triiodothyronine, which are typical adaptations to

life-extending CR in rodents.

 

PMCID: PMC2829643

PMID: 19904628

[Zeta]

 

This study [1] from 2013 would seem to shed some light on the relatively health advantages and disadvantages of shorter, more vigorous bouts of exercise vs. longer, less-intense exercise.

 

Not really, alas. (You had me excited!) You may have missed the erratum:

 

Correction: Minimal Intensity Physical Activity (Standing and Walking) of Longer Duration Improves Insulin Action and Plasma Lipids More than Shorter Periods of Moderate to Vigorous Exercise (Cycling) in Sedentary Subjects When Energy Expenditure Is Comparable

 

-- though the abstract you quote contains text from it (even though your link goes to thfe original paper).

 

Looks clear to me that we can't rule out a CR effect.

 

As for many of the other cited studies in this thread, it looks like energy-intake and -expenditure wasn't often taken into account.

 

We still need to know: for a given body weight, and, for a given energy-intake (very closely related, but not identical questions), what level and kind of exercise is optimal for health and longevity. I've seen no solid answers.

 

Zeta

[Dean Pomerleau]

Zeta,

 

I saw both the original paper and the correction, and tried to make sure my characterization of the study fairly reflected the actual results.

 

While far from perfect, I still thought it was interesting and informative to see long leisurely exercise (yes, with a couple hundred more calories burned) improved insulin sensitivity relative to a shorter more intense aerobic workout, in a crossover design that eliminates at least some of ambiguity due to individual variation.

 

But I agree with you that this was a small study that could have been more tightly designed and controlled to answer the question of which type and amount of exercise is optimal.

 

--Dean

[nicholson]

Hi Zeta:

 

"We still need to know: for a given body weight, and, for a given energy-intake (very closely related, but not identical questions), what level and kind of exercise is optimal for health and longevity. I've seen no solid answers."

 

And surely it will vary with age also, and frequency matters as well, in addition to quantity and kind?

 

Rodney.

[Zeta]

Rodney, agreed -- for ex. less intense exercise might be called for with advanced age.

 

While far from perfect, I still thought it was interesting and informative to see long leisurely exercise (yes, with a couple hundred more calories burned) improved insulin sensitivity relative to a shorter more intense aerobic workout, in a crossover design that eliminates at least some of ambiguity due to individual variation.

 

But the sound response could be one with a reversal of your parenthetical: "... to see a couple hundred more calories burned (via long leisurely exercise) improved insulin sensitivity". And that's no big surprise.

 

On my absurdly long to do list is: try to figure out the best form of exercise for glucose control (and, of secondary importance, blood lipid control). My brief forays into the subject previously led me to think that numerous short bursts of exercise could be as good as longer, leisurely exercise. That would be useful to know! I'd love to be able to save a little time by sprinting for 5-10 mins. 3-4 times/day instead of being on the exercycle for a total of an hour+.

 

 

Oh, Dean, something I've been meaning to ask you for a while now: how do you guard against skeleto-muscular injury? Maybe this should be taken in a diff. thread. My hips have been getting a bit sore, and a terrifying thought occurred to me: what would happen if I got bursitis or serious knee problems or whatever, and couldn't do aerobic exercise!! (Already have shoulder problems, so arm-based aerobic exercise is ruled out.) That would completely screw up my health regimen!!

 

Zeta.

[Dean Pomerleau]

Zeta,

 

But the sound response could be one with a reversal of your parenthetical: "... to see a couple hundred more calories burned (via long leisurely exercise) improved insulin sensitivity". And that's no big surprise.

 

On my absurdly long to do list is: try to figure out the best form of exercise for glucose control (and, of secondary importance, blood lipid control). My brief forays into the subject previously led me to think that numerous short bursts of exercise could be as good as longer, leisurely exercise. That would be useful to know! I'd love to be able to save a little time by sprinting for 5-10 mins. 3-4 times/day instead of being on the exercycle for a total of an hour+.

 

Hmm... The only way I can make sense of you not being surprised in the first paragraph (that long/leisurely exercise is better for insulin sensitivity than short/intense exercise) but still wondering about the relative benefits of long/leisurely vs. short/intense exercise for glucose control is the issue of the calorie expenditure. That is, you are unsurprised by the advantage of long/leisurely exercise if/when it also entails burning more calories.

 

I personally don't find this particularly surprising either, but I don't think this perspective is universally shared. In fact, I think there are plenty of people who believe you can maximize insulin sensitivity and glucose control without 'wasting' too many calorie (or too much time) on exercise, by keeping one's workouts shorter and more intense. 

 

For those people, I think the results of this study would be surprising and interesting, although since the contrast to long/leisurely exercise in this study was not a real HIIT-like workout (but one hour of vigorous cycling instead), there is still some room for uncertainty on this point, as I mentioned above.

 

Oh, Dean, something I've been meaning to ask you for a while now: how do you guard against skeleto-muscular injury? Maybe this should be taken in a diff. thread. My hips have been getting a bit sore, and a terrifying thought occurred to me: what would happen if I got bursitis or serious knee problems or whatever, and couldn't do aerobic exercise!! (Already have shoulder problems, so arm-based aerobic exercise is ruled out.) That would completely screw up my health regimen!!

 

I don't know exactly how I so effectively avoid skeleto-muscular injuries. I've been working out daily, with a variant of same routines of resistance training and aerobic exercise, for the last 30 years, since graduating from college. I've always chalked it up to my low-inflammation diet and lifestyle. Or maybe it's consistency that protect me  .

 

I did get a case of shin splits about a year ago, which were painful but not debilitating. At that time I reduced the running and increased the biking and walking, to reduce impact stress.

 

Oh yeah, this might be an important part of my success formula. When I do run (now ~2 miles / day), I do so in minimalist, 'barefoot' footwear (Vibram 5-fingers), and I run either on grass (on the golf course in my backyard) or on my soft-deck treadmill.

 

Barefoot, forefoot-strike running (as opposed to heal striking in normal running shoes) takes some getting used to, and requires a slow ramp up to avoid pain/injury, but I swear by it for avoiding running-related injuries.

 

--Dean

[Saul]

My RHR is in the verylow 40's.  I do one hour of vigorous aerobic exercise 6 days a week -- it's on the latest Precor with hand motion.  I do this at the maximum resistance -- to get some muscle strengthening as well.  The exercise causes sweating; I need to use a towel to wipe sweat from my brow after about 30min plus -- otherwise, the high saline sweat hurts my eyes.

 

Does the exercise burn many calories?  I don't think so.  There was once an interesting post by Al on this elliptical, indicating that the claimed number of burned calories by the Precor company is much too high.

 

My own observations -- skipping exercise for a week has zero effect on my weight (hardly a rigorous proof of anything).

 

But I believe, as does Luigi, that adding vigorous exercise (mostly aerobic) to CR is probably (my gut feeling is: "is almost certainly") a good idea.

 

Of course, what is optimal is unknown.

 

  -- Saul