"Extreme" Exercise - Good or Bad?

[corybroo]

High intensity training best for older people

The Generation 100 study is a cause-and-effect study.  One group was assigned to do high-intensity training intervals according to the 4×4 method twice a week, while group two was instructed to train at a steady, moderate intensity for 50 minutes two days a week. The participants could choose whether they wanted to train on their own or participate in group training with instructors.  The third group—the control group—was advised to exercise according to the Norwegian health authorities' recommendations. 

"Both physical and mental quality of life were better in the high-intensity group after five years than in the other two groups. High-intensity interval training also had the greatest positive effect on fitness,"

"In the interval training group, 3% of the participants had died after five years. The percentage was 6% in the moderate group. The difference is not statistically significant, but the trend is so clear that we believe the results give good reason to recommend high-intensity training for the elderly,"  Among the participants in the control group, 4.5% had died after five years.

"One challenge in interpreting our results has been that the participants in the control group trained more than we envisioned in advance. One in five people in this group trained regularly at high intensity and ended up, on average, doing more high-intensity training than the participants in the moderate group,"

the participants in all three of the Generation 100 study groups managed to maintain their fitness levels throughout the five-year period. That's quite unique for people in this age group, according to physician and Ph.D. candidate Jon Magne Letnes.

"Normally we see a drop in fitness of 20% over a ten-year period for people in their 70s. The fact that the participants in Generation 100 have managed to maintain their strong fitness levels from start to finish indicates that all three groups were more physically active than is usual for this age group,"

[A separate study published two weeks ago] contains information on 1500 healthy men and women who tested their fitness level twice, at ten years apart

 age has the least effect on fitness level for people who exercise regularly at high intensity. This group had a drop in fitness of 5% over ten years. By comparison, fitness levels dropped by 9% individuals who exercised regularly but not at high intensity. Those who were physically inactive lost as much as 16% of their physical conditioning over ten years

The decline in fitness was greater among the elderly than in younger people. Those who maintained their conditioning best also had the healthiest status when it came to risk factors for lifestyle diseases and poor health.

"Blood pressure, waist measurement, cholesterol and resting heart rate increased less in people who maintained their conditioning than in those who had a larger drop in fitness figures," 

She concludes by saying, "By high intensity we mean training that gets you really sweaty and out of breath. Now our hope is that the national recommendations for physical activity will be modified to encourage older people even more strongly to do high intensity training—either as their only form of exercise or to supplement more moderate training."

[Mike41]

https://www.sciencedirect.com/science/article/pii/S2095254618301005#fig0006
 

upper respiratory infections association with exercise. Just like most everything it’s a j curve. Excessive exercise being a major risk factor. 45-60 minutes of moderate to vigorous exercise being the most Effective in reducing risks. May be relevant wrt COVID-19 I’d be very surprised if it was not.

this would be consistent with Corybroos post above. Intense or vigorous is cool if not excessive 

Edited October 9, 2020 by Mike41

[Mechanism]

McCoy recently posted re: this fantastic interview- much more detail then the comparatively superficial TED Talk:

https://peterattiamd.com/jamesokeefe/

[Mike41]

On 10/29/2020 at 7:20 PM, Mechanism said:

McCoy recently posted re: this fantastic interview- much more detail then the comparatively superficial TED Talk:

https://peterattiamd.com/jamesokeefe/

I listened to it and was not impressed at all.

[Dean Pomerleau]

In this post from a 2016 exercise thread:

I highlighted a study which found that in obese and overweight pre-diabetic people, moderate exercise was better for glucose tolerance than a regime which was calorie equivalent by involved shorter bouts of more intense exercise (i.e. jogging vs. walking). Here is a quote from my overview of that study with new clarifications in [brackets]:

What's more, the "lots of moderate exercise" group [walking ~40min/day] exhibited better glucose tolerance improvements than  did the "lots of vigorous exercise" group, who expended the same amount of calories, but engaged in more intense exercise (jogging or equivalent) for a shorter period of time [~30min]. In fact, the equivalent amount [in calories burned] of more vigorous exercise did not significantly improve glucose tolerance at all. Surprisingly, the "some moderate exercise" group (brisk walking ~25min/ day) experienced  nearly twice as much improvement on the OGTT as did the "lots  of vigorous exercise" group [jogging ~30min/day].

The obvious weakness of this study was its inapplicability to folks around here who are not (typically) obese / overweight or pre-diabetic.

That why this new small study [1] of healthy people who already exercise is interesting, along with the fact that it involves various levels of High Intensity Interval Training (HIIT) - an exercise strategy that is popular with quite a few people around here for its time efficiency.

I can't seem to access the full text via sci-hub, so I'm relying on the author's description of the study in this NYT article: Too Much High-Intensity Exercise May Be Bad for Your Health (subscription required).

Here is the article's description of the study and the outcome:

They began by recruiting 11 healthy men and women who exercised but were not competitive athletes. These volunteers visited the researchers’ lab for tests of their current fitness and metabolic health, including blood-sugar levels over the course of a day.

Then the volunteers began an ambitious exercise program. During the first week, they performed two sessions of HIIT, repeating four-minute-long intervals five times on a stationary bicycle, with three minutes of rest in between. The riders pedaled as hard as they could during each four-minute surge, while researchers monitored their power output. Afterward, the researchers biopsied leg muscles and rechecked the riders’ fitness and 24-hour blood-sugar control.

During week two, the riders added a third HIIT session and ramped up the length of some of their intervals to a draining eight minutes. In week three, they worked out five times, with a mix of four-minute and eight-minute spurts of all-out pedaling. Finally, in week four, for recovery, they effectively halved the amount and intensity of their exercise. Each week, the researchers repeated all testing.

Then they compared how people’s bodies had changed week over week.

At first, the findings were encouraging. By the end of week two, the riders were pedaling harder and appeared to be getting fitter, with better daily blood-sugar control and more total mitochondria in their muscle cells. Each of these mitochondria was also more efficient now, producing greater amounts of energy than at the start.

But something began to go wrong during week three. The volunteers’ ability to generate power while cycling flattened, and their subsequent muscle biopsies showed sputtering mitochondria, each of which was now producing only about 60 percent as much energy as during the previous week. The riders’ blood-sugar control also slipped, with seesawing spikes and dips throughout the day.

After a week of lower-intensity riding, their mitochondria started to bounce back, producing more energy, but still 25 percent less than during week two. Their blood-sugar levels also stabilized, but again, not to the same extent as before. The riders could pedal, however, with the same — or even greater — vigor as in week two.

Taken as a whole, the monthlong experiment suggests that “HIIT exercise should not be excessive if increased health is a desired outcome,” says Mikael Flockhart, a doctoral student at the Swedish School of Sport and Health Sciences, who conducted the study with his adviser, Filip Larsen, and others.

In short, this small study seems to suggest that healthy, relatively fit people engaging in HIIT workouts too often may be counterproductive when it comes to glucose tolerance and mitochondria function. Three HIIT workouts per week seemed beneficial while five such workouts seemed like too much.

Interestingly, the abstract mentions that they tested world class athletes (who obviously engage in a lot of high intensity exercise) and found that "they had impaired glucose control compared with a matched control group." I would like to see the details of that but the full text isn't available. 

--Dean

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[1]  Cell Metab. 2021 Mar 13:S1550-4131(21)00102-9. doi: 10.1016/j.cmet.2021.02.017. 

Excessive exercise training causes mitochondrial functional impairment and decreases glucose tolerance in healthy volunteers.

Flockhart M(1), Nilsson LC(2), Tais S(2), Ekblom B(2), Apró W(3), Larsen FJ(4).

Exercise training positively affects metabolic health through increased mitochondrial oxidative capacity and improved glucose regulation and is the 
first line of treatment in several metabolic diseases. However, the upper limit 
of the amount of exercise associated with beneficial therapeutic effects has not 
been clearly identified. Here, we used a training model with a progressively 
increasing exercise load during an intervention over 4 weeks. We closely 
followed changes in glucose tolerance, mitochondrial function and dynamics, 
physical exercise capacity, and whole-body metabolism. Following the week with 
the highest exercise load, we found a striking reduction in intrinsic 
mitochondrial function that coincided with a disturbance in glucose tolerance 
and insulin secretion. We also assessed continuous blood glucose profiles in 
world-class endurance athletes and found that

DOI: 10.1016/j.cmet.2021.02.017

https://www.cell.com/cell-metabolism/fulltext/S1550-4131(21)00102-9

PMID: 33740420

[KHashmi317]

Some of my teeth have become a bit sensitive to temperature. Hot or cold. When I'm exercising, the I can test sensitive teeth if I glide my WARM tongue across them. There is some very mild soreness that goes away almost immediately if I continue to hold tongue against them. I'm guessing this has something to do with saliva getting dried out with heavy, open mouth breathing. 

So EXTREME and SUSTAINED EXERCISE may not be be good for dental health -- all else held equal.

https://www.dentistryiq.com/dental-hygiene/student-hygiene/article/16365655/the-effects-of-endurance-training-on-athletes-oral-health

https://www.colgate.com/en-us/oral-health/dry-mouth/how-to-keep-your-salivary-glands-healthy

[Saul]

Interesting.

Thanks Khrram.

  --  Saul