Sleep is like hitting the reset button every night. It's when your body is focused on recovery, stress levels are low, hormones are rebalancing, and you're recuperating for the upcoming day.
For men, sleep is when your body produces most of its testosterone levels. One study gathered a group of healthy men and tested their testosterone levels first thing in the morning after a night of sleep. The guys who slept for four hours had testosterone levels within the 200-300 ng/dl range.
However, the guys who slept for eight hours woke up with testosterone levels hovering between 500-700 ng/dl. The more sleep you get, the higher your anabolic hormones will be. So quit spending hours at night Googling "how to increase testosterone" and go to sleep.
Sleep deprivation can reduce insulin sensitivity, which can lead to fat gain, diabetes, and adverse heart conditions. One study found that lack of sleep impairs your body's ability to respond to insulin, one of the hormones that regulate your metabolism. In the study, seven healthy men and women spent eight days and nights in a sleep lab. On the first four days, they slept "normally." But on the final four days, their sleep was restricted to 4.5 hours.
After the four nights of sleep deprivation, blood tests revealed that the participants' overall insulin sensitivity was 16% lower than after the nights of normal sleep. Moreover, their fat cells' sensitivity to insulin dropped by 30% to levels typically seen in people who are obese or who have diabetes.
The senior author of the study said, "This is the equivalent of metabolically aging someone 10 to 20 years just from four nights of partial sleep restriction. Fat cells need sleep, and when they don't get enough sleep, they become metabolically groggy."
If you don't take sleep seriously, your body won't take building muscle seriously.
Plan what your week is going to look like. Set a goal time to get to bed every night that will allow for at least 8-hours of sleep. You'll increase growth hormone, keep your metabolism firing on all cylinders, and best of all, build muscle.
- Penev PD. Association between Sleep and Morning Testosterone Levels in Older Men. Sleep. 2007 Apr;30(4):427-32.
- Broussard JL. et al. Impaired Insulin Signaling in Human Adipocytes After Experimental Sleep Restriction: A Randomized, Crossover Study. Ann Intern Med. 2012 Oct 16;157(8):549-57.