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Exercise leads to ‘better’ sperm? TIME story doesn’t tell us by how much


4 Star


Exercise May Be the Key to Better Sperm

Our Review Summary

Running is part of their daily routineThis short Time magazine story describes a study that looked at whether the quality of semen could be improved through one of three different exercise approaches, compared to that of men who did not exercise.

The story did a good job establishing what made this study unique, and it included a comment from a source independent of the research. But, unfortunately it didn’t delve into enough specifics, such as providing numerical data about the different findings that could help readers better understand the research: What were researchers measuring, and by how much did those measurements change via the intervention? And it left out a very important limitation of the study: It didn’t look at whether these changes had any impact on fertility.


Why This Matters

The story rightfully points to semen quality as a major factor for couples facing infertility problems–but the study under discussion wasn’t designed to test if exercise has any impact on pregnancy rates. To not mislead readers, any connections drawn between exercise, sperm quality and fertility must be done very cautiously here, and that didn’t happen in this story.


Does the story adequately discuss the costs of the intervention?

Not Applicable

There was no mention of the cost of the methodology used in this study. Yes, in general exercise is free via walking or jogging, so we’ll rate this N/A. But, it’s worth pointing out that one of the studied exercise methods here–known as high-intensity interval training–was done on a treadmill, and may require paid expertise to learn how to do it safely and correctly.

Does the story adequately quantify the benefits of the treatment/test/product/procedure?

Not Satisfactory

There was no quantification of benefits provided in this story, only a statement that “all of the men who followed a physical activity program showed improvements in a variety of measures of their sperm,” compared to those men who were in the non-exercise group. The story states that, “the men in the moderate intensity, continuous activity program showed the most improvements compared to men in the other two more intense groups,” but it doesn’t characterize those improvements except in the vaguest of ways. Readers are left to wonder the degree of differences between the three exercise groups.

Does the story adequately explain/quantify the harms of the intervention?

Not Satisfactory

There is no mention of potential harms in this story. Because one of the exercise interventions was high-intensity interval training (HIIT), a brief discussion of harms was needed (see safety concerns of this PDF).

Does the story seem to grasp the quality of the evidence?

Not Satisfactory

The story does indicate it was a randomly assigned, controlled trial of 280 men, and it tracked them for six months. However, we’re not given any sense of the study’s limitations (an important one being that the study didn’t prove this intervention improved fertility).

Does the story commit disease-mongering?


No evidence of disease mongering here.

Does the story use independent sources and identify conflicts of interest?


The story does provide a quote from an expert unaffiliated with the research team, and we found no conflicts of interest that should have been noted.

Does the story compare the new approach with existing alternatives?


The story does suggest in the first paragraph other approaches to improving semen quality.  “Among the most (advice) dispensed: eat a healthy diet, keep a healthy weight, avoid alcohol and tobacco and stay away from certain medications, such as blood pressure and depression drugs.”

Does the story establish the availability of the treatment/test/product/procedure?

Not Applicable

Exercise — in this case, running — is clearly a readily available activity for most individuals.  They simply have to decide to do it. Some explanation of the availability of effective HIIT training could have been added, though.

Does the story establish the true novelty of the approach?


Novelty is established via this quote:

“This fits reasonably well with what we thought about the effects of exercise,” says Dr. Peter Schlegel, vice president of the American Society of Reproductive Medicine and chairman of urology at New York Presbyterian/Weill Cornell Medical Center. “But this is a much better done study than almost anything that’s been done before on the subject.” He notes that most previous studies did not randomly assign people to exercise groups and compare the outcome on sperm quality, but rather recorded sperm measures among men who reported their exercise habits after the fact.

Does the story appear to rely solely or largely on a news release?


There is no indication that this story relied on a news release.

Total Score: 5 of 8 Satisfactory


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