Some say a meta-analysis is like a large pile of small, weak, and insignificant studies lumped together into one ugly mess. Sort of like a stew made up of left-overs that might be getting a bit moldy. Others say that by aggregating studies which alone would be too small to amount to anything of significance, the data can gain significance by having a larger number of subjects from different studies put together to be counted.
Study Title: Adverse Metabolic Response to Regular Exercise: Is It a Rare or Common Occurrence?
Study Citation: Bouchard, C, Blair, S et. al. (2012) Adverse Metabolic Response to Regular Exercise: Is It a Rare or Common Occurrence?
Study Premise: There is a variability in peoples response to exercise. Some may experience adverse response to exercise. The authors state no study has addressed adverse changes in cardiovascular and diabetes risk factors can occur. The risk factors chosen to be studied include: “Sixty subjects were measured three times over a period of three weeks, and variation in resting systolic blood pressure (SBP) and in fasting plasma HDL-cholesterol (HDL-C), triglycerides (TG), and insulin (FI) was quantified.”
Study Conclusion & Media Announcements: Adverse response to exercise may occur. Some individuals do not respons positively in the measured according to the authors this analysis of 6 previous studies (a meta-analysis) revealed the shocking truth that some overweight people did not have a positive response to exercise and the variables mentioned above worsened. 7% had two variables worsen over the course of an exercise program.
Analysis: Why should one expect 100% positive response to any intervention? The fact that 90% had a positive or non-adverse impact on risk factors is an overwhelming number of individuals for whom exercise is likely quite good. Emphasizing the negative in which case “the minority is the new majority” seems to be the in thing to do in current culture and society. In everything from politics to social policy a majority may be declared at 40% (the U.S. Senate) or at 12-17% as was seen in misused statistics during health care reform debates. The fact that 8% to 12% is neither a majority, nor a vast number, and the “adverse events” were not death, disease or morbidity and mortality should alert those reading this article and the large headlines in the paper that hyperbole is at play.
There is an overwhelming amount of information that says exercise is good for you in many, many ways. In many cases exercise is the missing link to the best health you can have. Exercise is something that almost everyone should be undertaking (to avoid the undertaker). In fact a famous saying goes “where there is no exercise, the people perish”. Well, maybe it was “where there is no vision the people perish”.The reality is that where there is no exercise the people develop sarcopenia (muscle wasting), osteoporosis, obesity, depression, diabetes, high blood pressure, and dementia. So whether or not your high blood pressure goes down and your HDL-C goes up, there are many positive benefits to be achieved by exercising regularly.
Exercise and diet are both vital to overall health. All of the individuals in the studies this meta-analysis selected to include were overweight. Improper diet plays a large role in being overweight or obese.
Successful implementation of a healthy life plan should actually include more than a mere exercise program. It needs life habit modifications that would include good sleep habits, healthy diet, and avoiding the excessive consumption of things that are bad for you (too much alcohol, drugs, etc.). But exercise may be the largest change that is easy to make. Diet is also critical and often needs a tune up. Let’s sum this up in one sentence!
You can exercise and have a great shot at doing as well as you can or you can sit on a couch and take your chances!
- The study group only included overweight people with a BMI from 25-30
- Normal variablility in tests – is greater than zero
Bouchard, C, Blair, S et. al. (2012) Adverse Metabolic Response to Regular Exercise: Is It a Rare or Common Occurrence?
Bouchard C, Rankinen T (2001) Individual differences in response to regular physical activity. Med Sci Sports Exerc 33: S446–S451
deMello, V et. al. Insulin Secretion and Its Determinants in the Progression of Impaired Glucose Tolerance to Type 2 Diabetes in Impaired Glucose-Tolerant Individuals
The Finnish Diabetes Prevention Study. Diabetes Care February 2012 vol. 35 no. 2 211-217. Published online before print December 30, 2011, doi: 10.2337/dc11-1272
an adverse response was recorded if an increase reached 10 mm Hg or more for SBP, 0.42 mmol/L or more for TG, or 24 pmol/L or more for FI or if a decrease reached 0.12 mmol/L or more for HDL-C. Completers from six exercise studies were used in the present analysis: Whites (N = 473) and Blacks (N = 250) from the HERITAGE Family Study; Whites and Blacks from DREW (N = 326), from INFLAME (N = 70), and from STRRIDE (N = 303); and Whites from a University of Maryland cohort (N = 160) and from a University of Jyvaskyla study (N = 105), for a total of 1,687 men and women. Using the above definitions, 126 subjects (8.4%) had an adverse change in FI. Numbers of adverse responders reached 12.2% for SBP, 10.4% for TG, and 13.3% for HDL-C. About 7% of participants experienced adverse responses in two or more risk factors.