Your muscles grow while you are resting, so by not giving yourself enough quality Zzz, your body isn't able to recover and repair your muscles as well as it could if you were getting adequate sleep. In addition to being tired, another drawback of sleep deprivation is that important muscle-building hormones are negatively affected. These hormones include testosterone, growth hormone, cortisol and insulin.
Cortisol
This is a catabolic stress hormone which increases fat storage in the body and also aids in breaking down your hard-earned muscle tissue to use for energy. It has been proven that your body produces excess cortisol when you don't sleep enough.
Testosterone
The more testosterone you produce, the more muscle you can gain. Lack of sleep decreases testosterone production.
Growth Hormone
This important hormone regenerates your body and helps build and maintain muscle mass. Once again, skimping on quality sleep will decrease this hormone's production.
Insulin
Without enough insulin in your body, you're not able to maximize your intake of nutrients into your cells. Not getting enough sleep will cause your body to increase insulin production, and if your body produces too much insulin it can cause diabetes, excess fat storage, or even heart disease.
Your muscles grow while you are resting and sleeping, so by not giving yourself enough quality Zzz, your body isn't able to recover and repair your muscles as well as it could if you were getting adequate sleep.
