Snooze or Lose
Jerry BrainumSleep deprivation can crush anabolic hormones
While exercise is the primary catalyst for muscular growth, all such growth occurs when youíre at rest. Thatís why adequate recovery is so vital for making muscular gains. Studies show that if you donít get enough sleep, your testosterone levels may plummet as much as 40 percent. The body secretes maximum levels of growth hormone during sleep.
A new study using lab rats as subjects tested the hormonal effects of sleep deprivation.1 In previous studies animals deprived of sleep showed lower levels of thyroid hormones and a blunted immune response. Since the low level of thyroid output occurred in the hypothalamus, the researchers wanted to see how other hormones secreted in the same area of the brain were affected by sleep.
The experimenters found that sleep deprivation in the rats resulted in a suppression of other hormones, including growth hormone, insulinlike growth hormone 1 (IGF-1), prolactin and leptin. Corticosterone, the rodent version of cortisol, was unaffected by lack of sleep. That hormonal milieu favors a depression in anabolic reactions in the body, with an upgrading of catabolic effects, including possible muscle loss. Donít take sleep for granted if any type of muscular progress is your goal.
1 Everson, C.A., et al. (2004). Reductions in circulating anabolic hormones induced by sustained sleep deprivation in rats. Am J Physiol Endocrinol Metab. 286:E1060-E1070.