Resistance training does more than just sculpt your beach body. It improves immune function and stimulates metabolism, increased bone density, and production of vital hormones, amongst other things. But lifting weights demands good sleep for making gains and avoiding injury. Here’s why.
1. Sleep is anabolic
Muscle gets built in your sleep. Playing a key role in this process are two hormones, testosterone and human growth hormone (HGH).
Testosterone is released by the sleeping body in cycles paralleling our natural REM-to-non-REM 90-minute sleep cycles. Testosterone levels peak after a good night’s sleep (men experience this phenomenon as “morning wood”) and then decline throughout the day. Why is that important? Put it this way: synthetic forms of testosterone comprise the main ingredients of illegal anabolic steroids, the stuff that inflates the muscles and enhances the male sexual characteristics like the jaw and head size of power lifters. But testosterone doesn’t act alone. (Andersen and Tufik, Sleep Med Rev. 2008 Oct)
During the slow wave phase of non-REM sleep, the pituitary gland in your brain releases HGH, which became infamous over a decade ago for the benefits that its synthetic forms conferred to athletes looking to play harder and recover faster (Halson, Sports Med. 2014; 44). It’s indeed essential for recovery from injury, stress, and fatigue, while also promoting muscle growth. Oh, and it plays a role in the aging process, too, letting you look and lift like you did before your HGH levels—and testosterone levels, for that matter– began dropping in your mid- 20s.
Sleep deprivation, meanwhile, damages production of testosterone and HGH, degrading muscle mass and impeding muscle function, while promoting fat gain. It also can lead to injuries that keep you off the squat rack, a double-whammy because resistance training, like sleep, naturally elevates HGH.
2. Sleep feeds your muscles
You metabolize carbs and synthesize proteins in your sleep, so you’re essentially fueling and building your muscles. Sleep also promotes the function of insulin, which, to carry the metaphor, is like the fuel pump that delivers those vital carbs to the cells in your skeletal muscle. Sleep deprivation disrupts all of these processes (Halson, Sports Med. 2014; 44)
3. Sleep keeps you cool
Inflammation, from the Latin, means, “I ignite,” or inner-fire. It’s the body’s reaction to injury or infection. Systemic inflammation occurs with sleep deprivation, as does poor immune function. Both of these can keep you out of the gym while recovering from illness, and your muscles can be injured by systemic inflammation. (Calle & Fernandez, Nutr Res Pract. Aug 2010)
4. Sleep gives you wings
A good night’s sleep has been established repeatedly to improve mood and energy levels. Waking up refreshed and ready for the day is far better for your gym motivation than double-fisting energy drinks to make up for a late night Netflix marathon.
With all its cycles and anabolic gains; recovery and metabolic benefits; and mood and energy-enhancement, sleep is like a natural performance enhancing drug. Skipping your sleep deals a significant blow to your weight training goals.
- Don’t work out right before bed. While everyone’s sleep rhythm and recovery is different, late night lifting sessions tend to disrupt sleep cycles and promote poor sleep with an elevated heart rate.
- Embrace a nap: depending on your level of fitness, consider post-workout naps. There’s more anecdotal evidence than scientific, but many weight lifters testify to the benefits of a 30-minute nap after lunch or a late-morning or afternoon workout.
- Protein is good for muscles and it’s good for sleep, so feel free to make your bedtime snack protein-heavy. Peanut butter and apple or a bowl of cottage cheese will suffice. Your body tries to break down carbs and synthesize protein when you’re sleeping. It also absorbs protein from the digestive tract. Do try to stop eating 2-4 hours before bedtime though.