Study Claiming Exercise Makes Some People Worse Misses the Point

This study demonstrates that the medical tendency to focus on markers instead of genuine health outcomes has reached the point of utter absurdity.

by Heidi Stevenson

In a surprising finding, a study published in PLoS One found that as many as 12.2% of people who exercise are harmed by it. At least, that’s what the study concluded. What they’ve really done is mistake markers for cardiovascular health as if they were the real thing. It’s down this dangerous path that modern science keeps running, almost inevitably leading to a brick wall.

Titled “Adverse Metabolic Response to Regular Exercise: Is It a Rare or Common Occurrence?” and published 30 May 2012, the study measuried systolic blood pressure, HDL cholesterol, triglycerides, and fasting insulin.

The Study

The subjects were all people who had completed previous exercise studies. There were 1,687 men and women involved. After three weeks, they found:

• 8.4% had increases in fasting insulin.
• 12.2% showed increased systolic blood pressure.
• 10.4% had increased triglycerides.
• 13.3% had decreased HDL cholesterol.
• About 7% of the subjects experienced at least two of these “adverse responses”.

The authors stated that these “adverse effects” could not be explained by previous ill health, age, or amount of exercise. They also noted that there was no lack of improvement in cardiorespiratory fitness. They concluded:

Adverse responses to regular exercise in cardiovascular and diabetes risk factors occur. Identifying the predictors of such unwarranted responses and how to prevent them will provide the foundation for personalized exercise prescription.

But, the fact is that they did not demonstrate that people’s health was adversely affected by exercise! All they showed was that markers they presume to be indicative of health risk were adversely affected. At no point did they consider that, for these individuals, those changes might have been beneficial.

Markers Instead of Health Outcomes

The simple fact is that we are not made by assembly-line techniques. Each person is an individual, with a metabolism unlike that of any other person in the world. What’s good in one person is not necessarily good in another. An increase or decrease in a marker has no meaning by itself. In fact, these markers have never been shown to be consistent indicators for health outcomes.

Triglycerides are blood fats. It’s traditionally believed that high triglycerides are unhealthy. However, the study did not address whether the increase of triglycerides in some subjects moved them into a dangerous zone. In point of fact, we require fat, and the authors demonstrated nothing to show that any harm actually resulted from the increases. Isn’t it reasonable to assume that triglycerides in some people are inadequate to maintain health after exercise, which increases cellular activity, so the body would attempt to increase them?

Likewise blood pressure. Exercise increases the need to move blood around the body to increase nutrient and oxygen delivery and waste removal. Isn’t it possible that some people’s blood pressure would need to increase to accomplish that?

Insulin helps glucose enter cells. If a person has been exercising, is it unreasonable to believe that some require an increase in insulin to help get energy to cells that have developed greater needs as a result?

We’ll skip the whole cholesterol issue, because the simple fact is that its role in the body is badly understood by the medical profession, where it’s routinely treated as if it were a kind of fat, which it most assuredly is not. (See Cholesterol Doesn’t Cause Heart Disease – And It Isn’t a Fat for an explanation.) The focus on cholesterol—at least, in terms of it being bad, or good as in the HDL referenced by this study—is dangerously misguided.

Then, there’s the fact that the study lasted for only three weeks. The authors have absolutely no idea whether these changes were temporary or permanent!

The Real Findings (The Ones the Researchers Missed)

So what have the authors really demonstrated? It certainly isn’t that people are harmed by exercise! The authors presume that certain markers should change in a certain way when people exercise. They also presume that if they don’t, it must mean that exercise is harmful to those people.

The authors have shown only that those markers don’t always behave as they had expected. In no way have they demonstrated that the health of those people suffers!

Using markers as outcomes in studies simply misses the mark. The authors have, in fact, shown that to be true. The real issue is health and outcomes. Instead of focusing on markers in studies, which, as documented in Big Pharma’s Gaming of Medical Studies: Twisted Statistics and How to Spot Them, is a common error in medical studies, they should be designed to focus on what really matters: health outcomes.

Here’s what the authors suggest as a result of their findings:

We conclude that it is critical to search for potential physiological and molecular predictors so that individuals at risk for adverse response patterns can be identified and offered proper guidance in an exercise medicine preventive or therapeutic context.

In other words, they see it as yet another excuse to medicalize a normal human function: exercise. Worse, you can be sure that the term “therapeutic” means the development of drugs to treat and research to find more markers, with their associated tests that everyone who dares to exercise will be expected to take.

What would have been useful is to investigate the health of people who exercise, as opposed to those who don’t. Of course, that’s already been done, and it has consistently been shown that exercise is beneficial for virtually everyone, no matter what their health.

The authors have actually done a good job of demonstrating that the medical tendency to focus on markers instead of genuine health outcomes has reached the point of utter absurdity.

The graphic is from a photo by Andy Cross.
It has been modified from the original: rotated, cropped, filter added.
Please see Andy’s other work at
http://andyinnyc.tumblr.com/ and http://www.flickr.com/photos/andyinnyc/.

 

 

Tagged conventional medicine, exercise blood pressure, exercise hdl, exercise health, exercise health markers, exercise health risk, exercise insulin, exercise study plos one, exercise triglycerides, junk science, pseudo-science, pseudoscience