But the main goal of the study, given the participants, was to reduce heart disease risk. The pri…

But the main goal of the study, given the participants, was to reduce heart disease risk. The primary outcome the researchers were interested in was blood pressure, and the only group to see a significant reduction in blood pressure was the combination group—though it was only a small reduction of 4 mmHg in diastolic pressure (the smaller of the two numbers that describe your blood pressure). This group also saw an increase in aerobic fitness, like the cardio group, and increases in upper and lower body strength, like the weights group. And in a composite score of cardiovascular risk, which summed the contributions of blood pressure, cholesterol, lower body strength, aerobic fitness, and body fat percentage, the combo group was the only one to see a significant improvement compared to the control group.

When you read a paragraph like the preceding one, a few alarm bells should go off. With more than a dozen different outcome measures in a study where each group has barely more members than that, you’ll inevitably find some seemingly significant changes. The statistical analysis in this paper did apply a correction factor to account for the large number of outcome variables, but the fact remains that most of the observed changes were relatively small. It’s surprising, for example, that the aerobic exercise group didn’t see any improvement in blood pressure, in contrast with quite a bit of previous research. That’s probably mostly a result of the fact that eight weeks simply i