The Claim

Six hours after a single bout of strenuous anaerobic running, testosterone and androstenedione concentrations in male runners are reduced by 51% and 40%, respectively, compared to baseline levels, with a greater reduction than the 12% decrease observed during a day of normal activity.

Source: Effect of strenuous anaerobic running exercise on plasma growth hormone, cortisol, luteinizing hormone, testosterone, androstenedione, estrone and estradiol.

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
38score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

After a single intense sprint or high-intensity running session, testosterone and androstenedione levels in male runners drop by 51% and 40% within six hours, which is a larger decrease than the 12% drop seen during a regular day of normal activity.

See the scientific wording

Testosterone and androstenedione levels in male runners fall below baseline concentrations 6 hours after a single bout of strenuous anaerobic running, with reductions of 51% and 40% respectively, a decline more pronounced than the 12% decrease observed during a day of normal activity, suggesting a prolonged suppression following intense exercise.

Why this might work

Intense running triggers the brain to release stress hormones that signal the testes to stop making testosterone and related hormones, causing their levels to drop sharply for hours after the run.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: Effect of strenuous anaerobic running exercise on plasma growth hormone, cortisol, luteinizing hormone, testosterone, androstenedione, estrone and estradiol.

    After a hard sprint, this study found that men's testosterone and related hormones dropped way lower than normal six hours later—more than they drop on a regular day. So yes, intense exercise really does temporarily suppress these hormones.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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