Answered: Your Most Burning Questions About Workout

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  • December 25, 2018

“Do not lift loads for more than 45 minutes” they say in fitness tutorials. “If you do, your testosterone levels will drop, cortisol levels will go up and you’ll be stuck in a catabolic black hole you cannot escape. That does not remind you of anything?

No more than 45 min, really?

The idea that you should stop training after 45 minutes because you are reaching a kind of hormonal tipping point is a pretty silly thing. In fact, workouts lasting longer than 90 minutes have shown that they can increase testosterone levels above the “rest” level for 2 hours after the session are over.

The idea that the short-term hormonal response after training has a big impact on muscle growth is something that has been questioned in recent years.

In a study on the subject, researchers analyzed data collected from 56 healthy (but untrained) young men who participated in a 12-week resistance training program.

If the change in post-workout testosterone levels was so important for muscle growth, subjects with the greatest testosterone response after training would have had to build the most muscle. And those with the lowest response should have built the least muscle.

But, when they looked at the data, the researchers found no significant link between increased post-workout testosterone levels and gains in muscle strength and volume.

Bodybuilding preparation

What about cortisol?

Cortisol is generally considered a “catabolic” hormone that must be avoided to increase levels so as not to spoil the effectiveness of the session. If increasing post-workout cortisol levels put an end to muscle growth, you should see the men with the highest increase gain the fewest muscles.

Instead, the opposite has occurred. There was a weak but significant link between increased cortisol and dry mass gains, as well as growth of type II muscle fibers. The subjects with the greatest increase in cortisol levels were also those who gained the most muscles with upper body exercises.