Hormones & Individualized Muscle Growth
Updated: Aug 19, 2018
Hormones & muscle growth
When it comes to muscle growth the two hormones you need to focus on are testosterone and cortisol.
Male or female it doesn't matter, the key hormone for muscle growth is testosterone. If your training isn't effective in triggering testosterone release you will be hard pressed to build muscle.
On the flip side, too much cortisol will work against the action of testosterone, negating its positive effects. Cortisol is a catabolic hormone, meaning it breaks muscle tissue down. So if your training produces too much cortisol you will find it hard to make size and strength gains.
So the key then, to muscle growth is to MAXIMIZE testosterone release and MINIMIZE cortisol release.
Muscle Gain is Individualized
The truth about building muscle is that it's different for everyone. There is no hard and fast rule that accommodates everyone because everyone is uniquely different in how their body releases both testosterone and cortisol. While it's commonly assumed that heavy weight releases the most testosterone, studies have shown that it all depends on the individual.
Some people respond better to 8-10 reps and some to rep ranges of 15+ even though those rep ranges are commonly thought to be endurance rep ranges.
It's convenient to blame poor muscle growth results on genetics but the bottom line is that some people respond to the "common wisdom" on muscle growth (like heavy weight, lower reps) and others just don't.
What Does Science Say?
Two studies in the Journal of Strength and Conditioning assigned different exercise protocols to rugby players. The exercises were the same but the set and rep ranges varied from 4x10 with moderate rest; 3x5 with long rest periods, and 5x15 with only one minute of rest between sets.
You'd assume the 3x5 protocol gained the most strength and the 4x10 generated the most size but the studies showed that each protocol- even the high rep low rest one- stimulated high testosterone release in SOME individuals. In fact each person in the study had a unique hormonal response to the training. The same was true of cortisol. Some people released more cortisol in response to the high rep/low rest protocol, some to the heavy weight done at 3x5 and some to the moderate 4x10.
So Now What?
It's important to find a protocol that both 1) enhances your body's ability to release testosterone and 2) minimizes your body's release of cortisol. Obviously, in the real world we don't have easy access to equipment that can scientifically measure hormonal responses to exercise but there are several factors you can consider to get an idea of the effectiveness of your training.
How is your recovery? Some soreness should be expected, but if you are excessively fatigued or intensely sore it can indicate an imbalance in the cortisol to testosterone ratio which will mean results will suffer
Are you getting stronger? If gains in strength aren't being achieved and you aren't able to progress the weight you're using chances are the protocol you're on may not be optimal.
How's your energy? Hunger? Sleep? Mood? The first signs of lowered testosterone and elevated cortisol are a decline in energy, cravings for sweets, a dramatic increase in hunger, irritability, restless sleep, and waking up feeling tired. This why I always ask my clients about these factors. These measures act as biofeedback for me on how my programming is affecting the muscle building hormonal metabolism.
Ideally you want training to be intense enough to produce sufficient testosterone release but not to the point that excessive cortisol becomes an issue. It's difficult to look past old beliefs and entertain new ideas but the truth is that if 3x5 hasn't been working for you in terms of strength, it's not the protocol for you. Even if you've read otherwise. Just as people respond differently to nutrition and diet, guess what- they respond differently to training as well.