Fitness Friday: Sleep and Muscle Gain, Why You Build Muscle in Bed, Not in the Gym

Muscle repair happens overnight, not during your final set.

This week’s Fitness Friday is not about a new protocol, a new gadget, or a clever variation of anything. It is about sleep. The most boring performance tool available, and the one most people ignore.

You train. You lift. You increase the load and feel pleased with yourself. Then you sleep five or six hours and expect the body to adapt perfectly. It does not work like that.

Muscle protein synthesis, the repair and rebuilding process after strength training, rises after your session. But a significant part of that rebuilding happens during deep sleep. Restrict sleep and you reduce that building signal. At the same time, cortisol rises and testosterone drops. That combination does not favour muscle gain.

Most adults need seven to nine hours of sleep for optimal recovery. Consistently sleeping under six hours is linked with poorer glucose control, higher stress hormones, and reduced anabolic response. If you wake unrefreshed, feel flat in training, or plateau despite progressive overload, sleep is the first place to look.

Alcohol quietly interferes with this process. Even moderate intake reduces deep sleep and suppresses growth hormone release. Growth hormone supports tissue repair. A heavy training day followed by evening drinks means you limit some of the benefit from that session. Not catastrophic once, but consistent over time.

Late night screen exposure adds another layer. Blue light delays melatonin release and shifts your sleep later. That shortens total sleep time and often reduces deep sleep. The habit of scrolling before bed feels harmless. Physiologically, it chips away at recovery.

Training timing matters as well. High intensity sessions late in the evening raise adrenaline and core temperature. Both delay sleep onset. If evening training is unavoidable, you need a proper wind down routine. Lower lighting, slower breathing, and clear separation between stimulation and sleep.

Here is the message for today. You do not grow muscle in the gym. You stimulate it there. You grow it when you recover.

More volume is not always the answer. Better sleep often is.