When male athletes are overtrained, their body’s stress and growth hormone responses to low blood sugar don’t react as strongly—this could mean their brain’s hormone control center isn’t working right.

Athletes who are overtrained might have a less responsive stress and hormone system, which shows up as weaker hormone reactions during a special medical test.

Athletes who are overtrained might have messed-up hormone levels — like lower testosterone and higher stress hormones — which could explain why they feel so drained and don’t recover well.

For male athletes who train hard, checking a mix of things like mood, diet, body fat, and hormone reactions might be a better way to spot overtraining than just looking at one blood test.

Some athletes who are told they're just overtrained might actually be low on fuel — their bodies aren't getting enough energy or carbs — which can look like overtraining but is really a different condition called RED-S.

When athletes train too much without enough recovery, their brain and body systems—like brain chemicals, hormone responses, and muscle energy production—can go out of balance, leading to overtraining syndrome.