# Health Myths **URL:** \ **Category:** In My Humble Opinion\ **Created:** [July 3, 2014, 7:01pm UTC](https://boards.straightdope.com/t/health-myths/692292 "2014-07-03T19:01:14Z")\ **Posts on this page:** 3\ **Page:** 4

**Author:** ![DSeid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dseid/32/20194_2.png) [@DSeid](https://boards.straightdope.com/u/DSeid)\ **Post date:** [July 12, 2014, 4:11am UTC](https://boards.straightdope.com/t/health-myths/692292/61 "2014-07-12T04:11:09Z")

> [@Surreal](#): > > [Adverse Metabolic Response to Regular Exercise: Is It a Rare or Common Occurrence?](http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0037887) Thank you for sharing that but I do have to say it is a pretty weak analysis. _Assuming_ that the populations used in studies chosen for their analysis were normally distributed before and after interventions (which they implicitly do) we would expect 2.5% of all those measured to have changes in a negative direction by chance. Indeed the numbers they came up with, 8.4 to 13.3% depending on the study and the item, were more than that. Statistically significantly so? They offer no such analysis. But of course there is no reason to assume a normal distribution either before or after intervention. The only way to support the claim that a number outside 2 S.D. of test range above 2.5% represents an adverse response would be to compare it to the percent outside of that range for _the control population_ after the same amount of time. Do the studies cited show that? They don’t say. So let’s look at the studies themselves: [The HERITAGE study](http://care.diabetesjournals.org/content/28/1/108.full): notably had no nonexercise control group, showed variable magnitude of response that, in other analyses, do seem to link with particular genes, and none the same one whose testing kits is being sold by Timmons. [The DREW study](http://jama.jamanetwork.com/article.aspx?articleid=1108370): actually failed to show any difference on blood pressure between the control and the experimental exercise groups and such was not its intent. It set out to show that even mild exercise could impact measures of fitness and did so. It also would be expected that if movement in the negative direction was an effect of exercise (rather than statistics and effect of time on a cohort) that the negative movements would be more frequent in the higher than lower exercise groups; such was not seen. > [@](#): > > The primary finding from this prospective, randomized, controlled exercise trial in postmenopausal women is a strong (P\<.001) dose-response relation between the amount of exercise and change in fitness. This finding seems logical, but few reports in the literature from adequately powered studies with a tightly controlled exercise dose have evaluated the activity-fitness dose-response relation. Numerous randomized clinical trials support that accumulating at least 30 min/d of moderate-intensity physical activity on at least 5 days of the week, consistent with the 8-kcal/kg per week group in our study, has a beneficial effect on numerous physiological and clinical variables.10,11 Observational population-based studies indicate that this same activity dose is associated with a reduced risk of several chronic diseases and with increased longevity.22- 25 … The training intensity may have been too low and training at higher intensity may have generated a greater blood pressure response. There was no substantial weight loss associated with the exercise training, which may have blunted the benefits to blood pressure. Aging is associated with a loss of arterial elasticity and a subsequent increase in systolic blood pressure that may not be reversible in the short term by exercise alone.41 … [The INFLAME study](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2919641/): Another one that found no difference from exercise alone without weight loss on CRP. Indeed a certain percent had increases in CRP after the exercise intervention … about the same percent as in the control group - “The shape of the distribution of change values was similar between groups …” OTOH “there was a strong association between fat loss and change in CRP and that the individuals in the exercise group who lost the most weight (and fat) had a significant decrease in CRP. Our data suggests that exercise training-induced reductions in CRP are due primarily to fat loss …” STRRIDE also without a control group, found aerobic training resulted in a mean improvement in metabolic parameters that was not seen in resistance training alone. So on. One of the weakest analyses I’ve read in a while. Really. And if Timmons is somehow even implying that his product will identify who would be in those alleged adverse responder group (other than for the narrow result of lesser VO2 max response to aerobic training) than is he way out of line. ---

**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [September 3, 2014, 10:08pm UTC](https://boards.straightdope.com/t/health-myths/692292/62 "2014-09-03T22:08:43Z")

> [@psychobunny](#): > > I’ll give you that niacin has been shown not to be helpful, that there is insufficient data on fish oil and that use of statins for primary prevention of coronary disease, especially in those at low risk of heart disease and in women does not have the data that it does in other cases. In addition, there are many other factors besides LDL alone that govern cardiovascular risk. However, irrespective of actual cholesterol level, statins have definitely been shown to have a beneficial effect on prevention of cardiac disease [in diabetics](http://www.sciencedirect.com/science/article/pii/S0140673604168955) in patients [without coronary disease but with coronary risk factors](http://www.bmj.com/content/338/bmj.b2376.long) in patients with [prior coronary disease](http://informahealthcare.com/doi/abs/10.1185/030079902125000787) and even in the [general public](http://www.sciencedirect.com/science/article/pii/S0140673605673941). > > Here are the latest recommendations: > > The guideline recommends statin therapy for the following groups: > •People without cardiovascular disease who are 40 to 75 years old and have a 7.5 percent or higher risk for heart attack or stroke within 10 years. > •People with a history of heart attack, stroke, stable or unstable angina, peripheral artery disease, transient ischemic attack, or coronary or other arterial revascularization. > •People 21 and older who have a very high level of bad cholesterol (190 mg/dL or higher). > •People with Type 1 or Type 2 diabetes who are 40 to 75 years old. > (American Heart Association and American College of Cardiology guidelines November, 2013) > > tl;dr-don’t dis statins, they be good, yo! One of the articles you posted mentions how in a group of 1000 people about 48 vascular events are prevented by statins among people with existing CHD. Studies I’ve seen say it is closer to 2 out of 100. The treatment groups are possibly different, I don’t know. > [@](#): > > Taking all years together, the overall reduction of about one fifth per mmol/L LDL cholesterol reduction translated into 48 (95% CI 39—57) fewer participants having major vascular events per 1000 among those with pre-existing CHD at baseline, compared with 25 (19—31) per 1000 among participants with no such history. There was no evidence that statins increased the incidence of cancer overall (1·00, 0·95—1·06; p=0·9) or at any particular site. Other studies I’ve seen show about 2 events per 100 in a 5 year period. It says ‘taking all years together’ but later says 5 years. I’m confused by that. But if among high risk patients you have to treat 100 people to prevent 2 vascular events, and I’m not even sure what % of those vascular events are debilitating or fatal that still doesn’t sound uber impressive to me. Granted I’m not a physician but a person is likely to be in that group of 98 who sees no benefits than they are to be in that group of 2 who does see a benefit. Granted, among people with existing CHD the numbers are a little better, treat 100 people and prevent 5 events. But again, it is like with aspirin. Aspirin can help prevent heart attacks, but not fatal ones. So the mortality rating isn’t much different between the treatment group and the placebo group. [http://www.nytimes.com/2008/01/29/health/29iht-29well.9568465.html](http://www.nytimes.com/2008/01/29/health/29iht-29well.9568465.html) > [@](#): > > A 2006 study in The Archives of Internal Medicine looked at seven trials of statin use in nearly 43,000 patients, mostly middle-aged men without heart disease. In that review, statins didn’t lower mortality. Those studies as they say seem to be about middle aged men w/o heart disease. The study you posted finding 48 prevented per 1000 was among people with CHD. All in all, I’m happy to be educated about this subject. I have a background in chemistry but not in medicine, and I’ve become jaded about medicine in the last few years. But I’m still just not seeing a reasonable benefit unless you are in a very high risk group, and even then you are highly likely not to see a benefit and not be one of the people whose vascular event is prevented. I’m honestly so ignorant I don’t even know how CHD is even diagnosed. Do you have to have certain anatomical issues to have that diagnosed (arteries that are % clogged, issues on an ekg, stress test) or can they just diagnose you based on family history, weight, lifestyle, metrics readings, age? ---

**Author:** ![GrumpyBunny](https://avatars.discourse-cdn.com/v4/letter/g/bc8723/32.png) [@GrumpyBunny](https://boards.straightdope.com/u/GrumpyBunny)\ **Post date:** [September 3, 2014, 10:28pm UTC](https://boards.straightdope.com/t/health-myths/692292/63 "2014-09-03T22:28:08Z")

> [@RivkahChaya](#): > > One of my favorite health myths is the “[8 glasses of water a day](http://www.snopes.com/medical/myths/8glasses.asp).” (snopes link) My company (which should know better) sent that out as a mass email during our “Wellness Week”. The MDs in my department cheerfully shot it down. [Previous page](https://boards.straightdope.com/t/health-myths/692292.md?page=3)