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Exercising while reading and writing


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Dean, I am serious about investing in a new system where I can read and write while doing exercises. You are a great inspiration on this. Thank you.


I am 5’2.5”. Could you send me links to any stationary bike and desk that may work for me? Does the bike have to use electricity?

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Good for you. A quick search for "Dean bike desk" from the forum search page turns up this link to my post on the "Cool Tools" thread about my bike desk ($150 at Amazon). It doesn't used electricity, and you should check for yourself but it is quite adjustable so should it should fit you fine.


However, while it isn't very big, I know you are pressed for space Grace, so I'm not sure if your home (or your desk) can accommodate that model.


Coincidently, while grocery shopping at Aldi's yesterday, I noticed in their flyer for next week they are selling a very compact pedal exerciser for $29.99 that should work under any desk. Here is the link to the Aldi's pedal exerciser, although I don't think there are any Aldi's in your area (the only Aldi's in CA appear to be near Los Angeles).  Alternatively, Amazon has a pedal exerciser that looks very similar to the Aldi's one, but for $10 more ($39.95). 


Note - I can't vouch of either of them since I haven't tried them. I strongly suspect they will be inferior to the one I have if for no other reason than they are bound to have a much smaller pedal stroke. But for the price they can't be beat, especially if you've got limited room. In fact, I'll probably pick one up at Aldi's as a spare, given it's only $30.



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Always twirling, twirling, twirling towards truth in confusion!


Associations of sitting behaviours with all-cause mortality over a 16-year follow-up: the Whitehall II study





Background: Sitting behaviours have been linked with increased risk of all-cause mortality independent of moderate to vigorous physical activity (MVPA). Previous studies have tended to examine single indicators of sitting or all sitting behaviours combined. This study aims to enhance the evidence base by examining the type-specific prospective associations of four different sitting behaviours as well as total sitting with the risk of all-cause mortality.


Methods: Participants (3720 men and 1412 women) from the Whitehall II cohort study who were free from cardiovascular disease provided information on weekly sitting time (at work, during leisure time, while watching TV, during leisure time excluding TV, and at work and during leisure time combined) and covariates in 1997–99. Cox proportional hazards models were used to investigate prospective associations between sitting time (h/week) and mortality risk. Follow-up was from date of measurement until (the earliest of) death, date of censor or July 31 2014.


Results: Over 81 373 person-years of follow-up (mean follow-up time 15.7 ± 2.2 years) a total of 450 deaths were recorded. No associations were observed between any of the five sitting indicators and mortality risk, either in unadjusted models or models adjusted for covariates including MVPA.


Conclusions: Sitting time was not associated with all-cause mortality risk. The results of this study suggest that policy makers and clinicians should be cautious about placing emphasis on sitting behaviour as a risk factor for mortality that is distinct from the effect of physical activity."


"Relax" - a big hit for Frankie Goes To Hollywood

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Thanks Tom. Grace - an important skill for practicing CR, and life in general, is learning to think for oneself. Before reading further, take a moment to think about Tom's study and what its limitations might be.


Tom's study, which found no association between sitting time and mortality - is a single, rather small study. Here is a metaanalysis [1] involving 100 times as many people as Tom's study, which found overall a 34% increased risk of death in those folks who sat for the longest period each day.


And no, in case you are wondering, I don't think pedalling at a bike desk will have the same (detrimental) effects as sitting idlely, at least if you are pedalling with a modest amount of effort, as I do. But you definitely want to stand up and walk around regularly, whether you are pedalling while sitting or not.





[1] PLoS One. 2013 Nov 13;8(11):e80000. doi: 10.1371/journal.pone.0080000.

eCollection 2013.
Daily sitting time and all-cause mortality: a meta-analysis.
Chau JY(1), Grunseit AC, Chey T, Stamatakis E, Brown WJ, Matthews CE, Bauman AE, 
van der Ploeg HP.
Author information: 
(1)Prevention Research Collaboration, School of Public Health, University of
Sydney, Sydney, Australia.
OBJECTIVE: To quantify the association between daily total sitting and all-cause 
mortality risk and to examine dose-response relationships with and without
adjustment for moderate-to-vigorous physical activity.
METHODS: Studies published from 1989 to January 2013 were identified via searches
of multiple databases, reference lists of systematic reviews on sitting and
health, and from authors' personal literature databases. We included prospective 
cohort studies that had total daily sitting time as a quantitative exposure
variable, all-cause mortality as the outcome and reported estimates of relative
risk, or odds ratios or hazard ratios with 95% confidence intervals. Two authors 
independently extracted the data and summary estimates of associations were
computed using random effects models.
RESULTS: Six studies were included, involving data from 595,086 adults and 29,162
deaths over 3,565,569 person-years of follow-up. Study participants were mainly
female, middle-aged or older adults from high-income countries; mean study
quality score was 12/15 points. Associations between daily total sitting time and
all-cause mortality were not linear. With physical activity adjustment, the
spline model of best fit had dose-response HRs of 1.00 (95% CI: 0.98-1.03), 1.02 
(95% CI: 0.99-1.05) and 1.05 (95% CI: 1.02-1.08) for every 1-hour increase in
sitting time in intervals between 0-3, >3-7 and >7 h/day total sitting,
respectively. This model estimated a 34% higher mortality risk for adults sitting
10 h/day, after taking physical activity into account. The overall weighted
population attributable fraction for all-cause mortality for total daily sitting 
time was 5.9%, after adjusting for physical activity.
CONCLUSIONS: Higher amounts of daily total sitting time are associated with
greater risk of all-cause mortality and moderate-to-vigorous physical activity
appears to attenuate the hazardous association. These findings provide a starting
point for identifying a threshold on which to base clinical and public health
recommendations for overall sitting time, in addition to physical activity
PMCID: PMC3827429
PMID: 24236168  [PubMed - indexed for MEDLINE]
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You're welcome, Grace and Dean. And Dean is entirely correct when he urges to read the studies and draw one's own conclusions. Note, that n in the thousands is not generally considered "small" unless the condition the study is examining is extremely rare - we regularly here on this list take very seriously studies with f.ex. n=50 and the like; plus note how Dean emphasizes that the meta-analysis involved 100 times as many subjects - but it is indeed a meta-analysis (as he acknowledges)... i.e. it is not a study that involved 100 times as many subjects - a meta analysis involves drawing conclusions from studies with varying designs, which really is not the same thing as a single study with one design - in the "meta" step, you are once removed (since you need to make judgments about what to include and what exclude and why) and that extra step comes with an extra opportunity for confounders to creep in. The entire basis of statistics here is that a given sample size is considered representative of the population such that it includes all the variants of cases of the question studied in the same proportion as in the population at large; otherwise you'd never be able to draw conclusions from any "sample" by definition you'd have to examine each and every member of the population. Now ask yourself: does the "n" in the study I cited cover enough to be a representative sample? One hint would be: is the problem rare or common? If something happens 1 in a million, a sample of 100 is obviously inadequate, but isn't sedentary behavior as described supposed to be a big and prevalent problem that affects each and every person, and if indeed around 5.9% (Dean's meta-analysis) of all mortality can be laid at the foot of this problem, then you are talking about substantial numbers of people. The study I cited had roughly 5000 people in it, of which 450 died in the study period. So we ought to be able to see some 25-30 deaths due to the sedentary behavior described. But no adjustment of the data for the confounders they identified found any such effect. You be the judge of the validity of this. Note, that once you take into account the wild methodological and subject variability of the studies considered by Dean's meta-analysis, there is a lot less to the "100 times as many subjects" than meets the eye. 


In the interest of full disclosure: I personally actively practice sedentary behavior avoidance, by attempting during the course of the day to not sit still for more than 20 minutes - every 20 minutes I get up and walk around for 2 minutes. I am compliant with this practice most of the time (when awake, obviously), but not all of the time. YMMV. 

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You are perfectly right that a meta-analysis is very different from single study involving a large number of pooled subjects. But in some ways, a meta-analysis is better, since the authors can weight the various studies according to how well conducted they were, and it's harder to be mislead by either statistical anomalies or methodological shortcomings that can sometimes creep into single studies, particularly if they aren't very large. But as we've seen on several of studies of saturated fats, it's sometimes garbage-in, garbage-out. If all (or even most) of the studies in a meta-analysis are flawed, or the authors have a vested interest in getting a certain outcome, they can be as bad, or worse, than a single study.


In this instance, based on the meta-analysis I cited, and a number of other large recent studies (listed here), I appears to me that the evidence is pretty unequivocal - prolonged sitting is associated with increased mortality. It looks like merely fidgeting may attenuate the risk [1], suggesting to me that pedaling while sitting will be just fine.





[1] Am J Prev Med. 2016 Feb;50(2):154-60. doi: 10.1016/j.amepre.2015.06.025. Epub

2015 Sep 23.
Sitting Time, Fidgeting, and All-Cause Mortality in the UK Women's Cohort Study.
Hagger-Johnson G(1), Gow AJ(2), Burley V(3), Greenwood D(4), Cade JE(3).
Author information: 
(1)Health and Social Surveys Research Group, Department of Epidemiology and
Public Health, University College London, London, United Kingdom. Electronic
address: g.hagger-johnson@ucl.ac.uk. (2)Department of Psychology, School of Life 
Sciences, Heriot-Watt University, Edinburgh, United Kingdom; Centre for Cognitive
Ageing and Cognitive Epidemiology, University of Edinburgh, Edinburgh, United
Kingdom. (3)Nutritional Epidemiology Group, School of Food Science and Nutrition,
University of Leeds, Leeds, United Kingdom; (4)Nutritional Epidemiology Group,
School of Food Science and Nutrition, University of Leeds, Leeds, United
Kingdom;; Division of Biostatistics, University of Leeds, Leeds, United Kingdom.
INTRODUCTION: Sedentary behaviors (including sitting) may increase mortality risk
independently of physical activity level. Little is known about how fidgeting
behaviors might modify the association.
METHODS: Data were from the United Kingdom (UK) Women's Cohort Study. In
1999-2002, a total of 12,778 women (aged 37-78 years) provided data on average
daily sitting time, overall fidgeting (irrespective of posture), and a range of
relevant covariates including physical activity, diet, smoking status, and
alcohol consumption. Participants were followed for mortality over a mean of 12
years. Proportional hazards Cox regression models estimated the relative risk of 
mortality in high (versus low) and medium (versus low) sitting time groups.
RESULTS: Fidgeting modified the risk associated with sitting time (p=0.04 for
interaction), leading us to separate groups for analysis. Adjusting for
covariates, sitting for ≥7 hours/day (versus <5 hours/day) was associated with
30% increased all-cause mortality risk (hazard ratio
=1.30, 95% CI=1.02,
1.66) only among women in the low fidgeting group. Among women in the high
fidgeting group, sitting for 5-6 hours/day (versus <5 hours/day) was associated
with decreased mortality risk (HR=0.63, 95% CI=0.43, 0.91), adjusting for a range
of covariates. There was no increased mortality risk from longer sitting time in 
the middle and high fidgeting groups.
CONCLUSIONS: Fidgeting may reduce the risk of all-cause mortality associated with
excessive sitting time. More detailed and better-validated measures of fidgeting 
should be identified in other studies to replicate these findings and identity
mechanisms, particularly measures that distinguish fidgeting in a seated from
standing posture.
Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier
Inc. All rights reserved.

PMID: 26416340 

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"Attenuated" risk is a stretchy term. What qualifies as 'fidgeting'? I agree that biking is most certainly going to be at the very high end of fidgeting, but we are talking about the possible inherently different physiological reaction of standing vs sitting, period. Note this eyebrow raising statement in the study you cited, Dean: "overall fidgeting (irrespective of posture)" [bolding mine, TBA). Wouldn't driving a public transport bus (especially one without power-steering or automatic transmission) in winding city roads qualify as "fidgeting", especially compared to sitting on a couch watching TV and snacking, or sitting in a cubicle surfing the net? But if it does, then how "attenuated" is the risk given the old London bus driver study:





And at 31,000 subjects who were pretty homogenous in key respects, it's not a "small number", and as pointed out in the study, statistically significant. How does that square with your study wrt. "fidgeting"?


The London study focused on CHD, not all-cause mortality, but if they could get robust results along just the CHD axis, then one imagines that all-cause would only strengthen that effect (unless somehow sitting protected against other causes of mortality than CHD - not a likely possibility). Of course, a big limitation here is that we don't get granularity with regard to the variable of voluntary free time (as opposed to work-time) physical activity and resulting fitness levels - were the bus drivers more or less or equally likely to exercise compared to the other workers... but why would the profession of bus driving predispose one to have different free-time exercise habits compared to f.ex. conductors?


Bottom line: I think we need to think carefully whether the key factor here might not be strictly postural. In other words, regardless of whether you are expending energy biking, or whatnot, if you are sitting, your physiology is different compared to if you are standing, and energy expenditure cannot be the sole differentiating factor between those two postural states.

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I hear where you are coming from, but I don't follow your logic. Let me see if I can spell out your premises and your conclusion, so you can help clarify how the latter follow from the former:



  1. Sitting appears to be detrimental for health/mortality.
  2. Overall fidgeting (irrespective of posture) seemed to override the detrimental effects of sitting
  3. London bus drivers would seem to qualify as engaging in a lot of "fidgeting" while sitting, for some definition of fidgeting.


  • Sitting is bad - period, even if one is biking while seated.

While I'll readily admit that the fidgeting study (PMID 26416340) is pretty weak. From the full text the measure of fidgeting was based solely on subjects' self-reports (i.e. they were asked "On a scale from 1 to 10 please indicate how much of your

time you spend fidgeting?").
But it seems like a stretch to generalize from the poor health of London bus drivers despite their activity while seated in order to suggest that other, more rigorous seated activities like biking will be detrimental for health simply because they are done in a sitting position.
BTW, I too take frequent breaks from my bike desk to stand up and move around. 
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To clarify: I find the fidgeting study to be weak and contradicted by the London study, based on the weakness of not rigorously defining fidgeting when applied to the postural variability, whereas the London study would have per necessity very clearly defined "fidgeting" as the range of movements the drivers engage in would be quite set for all of them (in fact it would be a remarkably consistent standard). Therefore, I doubt fidgeting is much of a factor. But given the wide disparity between the still fairly non-trivial expenditure of energy by bus drivers and trivial expenditure of "true" sedentary behavior (TV watching, computer net surfing etc.), I would place biking under the desk as closer to the bus drivers than the "true" sedentaries. In other words, I don't believe there would be an extreme gulf between the expenditure of energy by bus drivers and by under-the-desk bikers - the energy delta between either of them and the TV watchers would be greater. But we don't have studies on under-the-desk bikers - we only have studies on bus drivers. But since bus drivers and desk bikers are close to each other in energy expenditure (compared to TV watchers), I - LEAP IN REASONING - surmise that what applies to bus drivers would also apply to desk bikers. And that is that we are focusing on the wrong variable - energy expenditure - whereas the real variable (I speculate) is posture. What bus drivers and TV watchers share is not energy expenditure (in fact, there is a substantial difference), but posture - both sit. And that seems to be the problem (I speculate) - not the energy expenditure. 


Think of an analogy. Exercise induces a greater heart rate. It would be the wrong variable to focus on heart rate alone as determinative of how hard you're exercising. You could also take amphetamines which would accelerate your heart rate (and make you lose weight, ANOTHER effect of exercise), but your health outcomes would not be the same as with exercise. Fen-phen made you lose weight - and damaged your heart. Exercise made you lose weight but made your CV health better (perhaps dose dependently?). Faster heart beat by amphetamine = bad, by exercise = good (in the case of exercise, perhaps also dose dependent). 


I am saying the same thing: energy expenditure is not the variable to focus on in sedentary behavior effects. Instead, posture is. You can drive a bus or bike under the desk or watch TV, but you are sitting. We know for a fact that the physiology changes when you change posture - different hormones and effects (f.ex. lipoprotein lipase) - and therefore energy expenditure cannot be the only factor. Think of that even within the context of exercise itself: there is aerobic and anaerobic - both are excercise. But unless you do your muscle training while also incorporating elements that work your CV system directly (circuit training), you are NOT doing much directly to affect your CV health - there are many reports of exclusively muscle exercisers (especially body builders) who have serious CV problems. Whereas specifically aerobic exercise - even in the absence of weight training - does help your CV health. That shows you that energy expenditure by itself is not the sole variable.


I even think there may be something to the effect of posture in overlong sleepers having higher all-cause mortality. They spend less time in an upright/standing posture. They are lying more (or sitting - as in the middle ages people frequently slept in specially designed chairs). Now, of course, I am not claiming for one second that that's the most important or even particularly big variable when it comes to sleep, but it might be an additional small factor.


Bottom line: it's about posture.


Now I don't know if my speculation is correct, but that's the logic and reasoning I'm employing (clarifying, since you asked, Dean).

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Thanks for the clarificationn. I acknowledge that it could be the posture, but I question your suggestion that driving is more like under-the-desk biking than sitting watching TV - at least the way I use my bike desk. Here are the calorie expenditures per hour for the three activities and for someone my weight, according to CRON-O-Meter:


                                          kcal/hr (above BMR)

Sitting watching TV                  18 

Driving                                    89

Leisurely Biking (9.4mph)         283


I actually bike at my desk at about 11 mph and 80 RPM, with resistance about equivalent to biking on flat ground - so I estimate I expend around 300kcal/hr.


Clearly, by these numbers driving is a lot closer to passive sitting than it is to the way I pedal at my bike desk, which would (or at least could) explain the poor health of the London bus drivers.



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In this post earlier in this thread, I pointed to several inexpensive pedal exercisers, including one available on sale at Aldi's this week, and a similar one on Amazon. 




I purchased the Aldi's one this afternoon and just tried it out. It's terrible. It slips across the carpet, is friction (rather than flywheel or magnet) based - making it extremely un-smooth to pedal, the resistance is pitifully low, and the stroke circumference is tiny.  Overall, it's a terrible product. I'm virtually certain the Amazon one $39 Amazon version of will be just as bad. I'm bringing it back to Aldi's and getting my $30 back.


It make me all the more impressed and appreciative of the $150 Exerpeutic bike I do have. While bigger and more expensive, it's like night and day compared to the cheap Aldi's model in terms of quality and functionality. 



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Dean and Tom, thank both of you for presenting studies that produced different or opposing results. Since both of you are personally active and set limits on the time duration you sit, I have decided on having Dean’s bike. I just placed the order. Thanks again!

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For anyone who is looking for an under-desk pedaling solution, but may not have the room for the Exerpeutic bike that I have and highly recommend, today on Amazon you can get a low-profile elliptical pedal machine for $120 with free (Prime) shipping. That is apparently a deal since it usually sells for ~$170, according to Kinja deals.


Unlike the crappy Aldi's one I bought and returned, this one uses magnets to produce resistance, like my Exerpeutic bike which is very smooth and quiet. While I haven't tried it so I can't vouch of it, it has a lot of good ratings on Amazon. So it might be worth considering. Below is an image of what it looks like. That guy looks happy with it .





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Dean do you have a blog? Because I feel like if this site goes belly up you'd need to fill an unmet vacuum.


I do have a blog, it's called Thoughful Cog. I don't post to it very often - only when I have something original to share that I think might have broader appeal than, and not be exclusively relevant to, the CR Forums. And even then I don't usually post there.


If the CR Forums were to disappear or become a real ghost town, I'd probably seek out another forum community of like-minded individuals, perhaps like Longecity.org (under discussion here) or even LivingTheCRWay.com, rather than try to ramp up my blogging activity.


It is very difficult to build a vibrant community, but it is even harder to build a following for a blog, particularly if one isn't interested in selling oneself on social media. Plus, the linearity of blogs (even with comment sections enabled) makes it very difficult to have many open discussions you can post to / engage on whenever new information or questions comes along. That's what I really like about these forums - there is such a nice structure in place (with so many interesting and content-full threads) that it's easy to post new content, and have some context within which to place it, and a history of related discussions. That would be very hard to rebuild anywhere else.


Some days, when it's really quiet around here, I tend to think of the CR Forums as my own personal blog, without the limitations of linearity associated with a normal blog. This kind of forum-as-personal-blog strategy is not without precedence but I hope it doesn't come to this:


Back in 2010, a long time ago in internet years, a fan forum for Buffy the Vampire Slayer called “The Bloody Board” was thriving with nearly 40,000 posts.
Its creator, a 27-year-old Australian woman calling herself Jamie Marsters (a feminised tribute to James Marsters, the name of the actor who played Spike), presided over hundreds of threads hosting a stream of updates about Buffy cast appearances at conventions and on other shows (the final episode of Buffy had aired in 2003). The “General Discussion” section leaned heavily towards posts about Marsters’s namesake, the blonde vampire anti-hero. There were links to photo shoots, interviews, a poll asking “Which vampire hook-up is the hottest?” For Buffy fans, it was a hub of news and conversation.
The catch? These conversations were almost always one-sided, with Marsters only talking to herself. Essentially, it was a forum with only one member.


There are several ironic aspects to this Buffy the Vampire Slayer forum story. First, it was a forum focused on entities that live forever (vampires). Second, the sole-proprietor of it persisted in (solo) discussions of the topic for many years after the show had gone belly up - in a way not dissimilar to the loss of faith that many folks have had relative to the miraculous potential of CR to extend lifespan. Finally, I have the habit of talking to myself in some of my posts (e.g. here and here - search for "But Dean"), like she was apparently doing, simply to have someone to serve as a foil and bounce ideas off of...



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