Sunday, February 1, 2015

Exercise at reasonable doses is beneficial to health

Background

Even though you never specifically read him say "Exercise kills you", there is a distinct undertone in his writings against any kind of vigorous exercise, especially endurance exercise. He is only supportive of concentric weight training, low-intensity activities such as walking or very short high intensity exercise, but he also doesn't seem to mind much when one lives entirely sedentary. 
“The overlapping effects of estrogen, polyunsaturated fats, exercise, serotonin, histamine, lactic acid, nighttime, and hyperventilation, tend to be cumulative and self-stimulating. Degenerative changes in tissues are accelerated by all of these stress mediators.” - Ray Peat
"Exercise increases blood clotting, and so can increase the risk of strokes and heart attacks. [...] Walking is a better form of exercise." - Ray Peat
"Exercise, like aging, obesity, and diabetes, increases the levels of circulating free fatty acids and lactate."- Ray Peat
"Hypothyroid people, who are likely to produce lactic acid even at rest, are especially susceptible to the harmful effects of “aerobic” exercise. The good effect some people feel from exercise is probably the result of raising the body temperature; a warm bath will do the same for people with low body temperature." - Ray Peat
“Endotoxin (like intense physical activity) causes the estrogen concentration of the blood to rise.” - Ray Peat
Those are some pretty harsh statements. But are they actually true? Does endurance exercise really cause degenerative diseases such as heart disease? Is resistance exercise really better than endurance exercise? Does endurance exercise increase estrogen? Is it better to just sit on the sofa?

Evidence from association studies

Looking in the study databases will quickly give you loads of studies that indicate that exercising more is associated with reduced mortality and morbidity compared to not exercising at all or only rarely:

  • Mortality of elite (!) endurance and mixed endurance-resistance athletes is reduced compared to the general population. For pure resistance athletes less consistent results were found, some found increased mortality. http://www.ncbi.nlm.nih.gov/pubmed/19574095
  • In patients with coronary heart disease, regular strenuous physical activity between 5-10 hours per week (or 2-6x per week) is associated with reduced cardiovascular and all-cause mortality. At very high regular physical activity levels (daily strenuous activity; over 19 hours per week) there was an association with increased mortality, albeit still lower compared to people who did not exercise at all. http://www.ncbi.nlm.nih.gov/pubmed/24829374
  • Regular joggers have significantly reduced mortality compared to non-joggers. http://www.ncbi.nlm.nih.gov/pubmed/23449779
  • A high amount of sedentary activity is associated with higher all-cause, cardiovascular and cancer mortality, irrespective of physical activity.                                http://www.ncbi.nlm.nih.gov/pubmed/25599350
  • People that newly start vigorous physical activity compared to people who don't change their activity level is associated with reduced all cause mortality, to a similar level of people who were continously active through the whole surveillance period. http://www.ncbi.nlm.nih.gov/pubmed/8426621

Evidence from interventional studies

Now, a knowledgable peatarian will say that these are just population studies, and it is clear that people who are healthier in the first place move more, while people who are sicker move less (although the last study somewhat argues against that). Point taken, so lets look at the randomized controlled trials of exercise interventions which eliminate this problem:

  • A meta-analysis of randomized controlled trials of total 10,794 patients with coronary heart disease who got exercise-based rehabilitation vs. usual care showed that exercise reduced cardiovascular mortality and showed a trend of reduced all-cause mortality. http://www.ncbi.nlm.nih.gov/pubmed/21735386
  • A meta-analysis of randomized controlled trials of total 2,188 patients with stroke comparing endurance, resistance, mixed and no training, showed reduced disability scores with exercise training. Not enough data was available for a conclusion on mixed or resistance training or on total mortality (although there were less deaths in the exercise groups). http://www.ncbi.nlm.nih.gov/pubmed/24142492
  • A meta-analysis of randomized controlled trials of total 4740 patients with heart failure comparing exercise vs. no exercise showed a trend of reduced all-cause mortality in the exercise group and significantly improved quality of life and reduced hospital readmissions. http://www.ncbi.nlm.nih.gov/pubmed/24771460
  • A notable long term study in heart failure patients compared 10 years of relatively boring aerobic cycle ergometer or treadmill exercise (moderate intensity; twice weekly for one hour) vs no exercise training and found significantly reduced cardiac mortality and hospital readmissions along with improved quality of life. http://www.ncbi.nlm.nih.gov/pubmed/22999730
  • A randomized controlled trial in 262 sedentary patients with type 2 diabetics showed a reduction of insulin resistance by both endurance and resistance exercise (a slight trend of endurance being better). A combined training showed the best results. http://www.ncbi.nlm.nih.gov/pubmed/21098771
  • A randomized controlled trial in 154 adults showed that endurance exercise with jogging, biking and brisk walking reduced duration and severity of respiratory infections compared to controls. Beneficial effects were also seen in an interesting third group of meditation. http://www.ncbi.nlm.nih.gov/pubmed/22778122
  • A meta-analysis of randomized controlled trials in breast cancer patients showed that exercise interventions significantly improved quality of life and reduced fatigue compared to no exercise. The trials were not powered to show differences in mortality. http://www.ncbi.nlm.nih.gov/pubmed/16818906
  • A randomized controlled trial of endurance exercise in overweight postmenopausal women showed that exercise significantly reduced serum estrogen levels compared to no exercise. http://www.ncbi.nlm.nih.gov/pubmed/15087413
  • A randomized controlled trial in patients with mitochondrial myopathy showed improved symptom scores and higher exercise capacity in the exercise vs the control group http://www.ncbi.nlm.nih.gov/pubmed/15962332

Conclusions

There is very good evidence from both observational as well as interventional studies that exercise is healthy. The argument that resistance exercise is to be preferred and endurance exercise to be avoided is not supported by the data. As with nearly everything in life (food, supplements, lifestyle), there is a J-curve like distribution, with both too much and too little exercise probably being harmful. But even acknowledging that, extreme exercise is still associated with lower mortality than no exercise at all. 

Another popular argument is that you should not exercise when you are hypothyroid or sick. This is also not supported by the data, as seen by the effect of exercise in people with heart failure and other disorders that are associated with severe metabolic and mitochondrial impairment. If exercise had made those metabolic conditions worse as Peat suggests, it would have also lead to worse outcomes. But as the opposite happened, it is likely that exercise improved both metabolism and mitochondrial health (e.g. 1, 2).

So in summary, the anti-exercise sentiments in Ray Peat's articles will likely deter more people from conducting reasonable-dosed exercise, than educating the small fraction of extreme-athletes from bringing their activity level down to physiologic levels.

5 comments:

  1. Anonymous29/5/15 18:12

    Many people in the modern world are in a chronic state of physiological stress. Exercise, especially intense exercise, is fundamentally taxing physiologically, and tends to call upon reserve energy. When reserve energy is inadequate, the body enters a stress state.

    It seems fundamentally illogical to recommend something taxing to people whose energy reserves are already inadequate, yet this is what doctors and health gurus tend to do. Rather than applying the band-aid solution of exercise, more focus should be placed on increasing the reserve energy and physiological state of the individual.

    ReplyDelete
    Replies
    1. As said above, the above mentioned evidence shows the opposite of what you suggest. Where is the evidence that exercise is harmful? Where is the evidence we should rather "increase the reserve energy"?

      Just because something sounds logical or illogical, it doesnt meant it is true or false - it's the empirical evidence that really informs us. Peatarians should not ignore this, otherwise they will always be deluded by circular arguments that are so popular in this scene.

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    2. I see evidence but I still don't want to change my view on Ray Peat? Why??? I think Ray Peat's concepts fit lazy people like me, and anything making me less lazy will have huge obstacles to overcome.. I don't know. I like Peat, it's probably pseudo science for lazy people.

      Delete
  2. Anonymous11/8/15 23:47

    For the first study, the experimenter said the "review is still predominantly male, middle aged and low risk". The research was basically spinning numbers on other researchs: "RCTs have been identified by searching CENTRAL, HTA, and DARE...". Usually something is empirically strong when you can repeat the process. Why back up your viewpoint with weak studies like this.

    Ray Peat is probably wrong and if you read his opinions, you'll see he does change his mind. You can see his opinion changes as you read his articles throughout the years. For example, he used to recommend eating fibers in the 1980s, but now he recommends not eating fibers except 1 grated carrot a day. So it's not like he is ignoring opposing data sets.

    Anyways, the studies Ray Peat used to advance his view seems more reproduce-able. Wish you luck in exploring physiology and health. I don't know who is right either, I wish we have definite knowledge of what our bodies are doing rather than some statistical tendencies and no explanation behind those tendencies.

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  3. Anonymous15/4/19 09:57

    https://well.blogs.nytimes.com/2012/09/19/is-30-minutes-of-daily-exercise-a-sweet-spot-for-weight-loss/

    ReplyDelete