Does too much cardio lower testosterone?

Moderate cardio won't lower your testosterone — but chronic, excessive endurance training can. The blanket claim that “cardio kills testosterone” is one of the most persistent gym myths, and the truth is more useful than the scare story.

For normal amounts, cardio is good for your hormones, not bad. Moderate aerobic exercise improves your body composition and insulin sensitivity and lowers visceral fat — all of which support healthy testosterone. A man who walks, cycles, or runs a few times a week alongside lifting is doing his testosterone a favour, not harming it.

The real exception is the endurance extreme. Men training at very high volumes — marathon and ultra-distance levels — especially while under-eating, can show measurably lower testosterone. But the cause usually isn't the cardio itself; it's the chronically elevated cortisol and the energy deficit that come with hours of training and not enough food or recovery. Your body reads “constant exertion plus too little fuel” as a stress state and dials hormone production down. The same thing rarely happens to someone doing two or three sensible sessions a week.

So the question isn't really “does cardio lower testosterone” — it's whether your overall training load and nutrition are sustainable. Volume without recovery is the problem, not movement.

What to do: keep cardio in your routine — it's good for your heart, your waistline, and your hormones. Just don't bury yourself in high-volume endurance work while under-eating and under-recovering. Pair your cardio with strength training, eat enough to fuel it, and prioritise recovery. Done that way, cardio is an asset to your testosterone, not a threat to it.