Can Late Day Exercise Cause Insomnia?

Exercise is good for you. Late day exercise should be beneficial, right? Not necessarily and here is why.

Exercise pushes the body to exert an amount of energy that exceeds the amount needed for the normal daily activities. Exercise causes the muscles to produce all manner of chemicals, the products of various biochemical reactions. Late day exercise can overburden the muscles with those chemicals. Until the body cells can deal with those chemicals, the exerciser could well experience insomnia.

Late day exercise takes the body a step away from the state that acknowledges the approach of the sleep cycle. When you are getting sleepy your body has initiated its movement into the sleep cycle. Before the body can enter Stage 1 of the sleep cycle, it must undergo certain needed changes.

Most people can not think as fast at night as they can in the morning. At night their bodies have started to slow down. Their muscles have become less tense. The level of their muscle tension represents the level of tension that the body associates with sleep. Late in the day, the body has strayed quite a bit from the optimal state for engagement in an exercise activity.

The body slows down late in the day, so that it can better move into Stage 1 of sleep. Late in the day, the body stands ready to allow the brain waves to become smaller. As the brain waves become smaller, random thoughts start to filter through the mind. Such thoughts represent movement into Stage 1 sleep.

A person in Stage 1 sleep could easily respond to a loud noise. Such a noise would bring that person to a state of wakefulness. He or she might then find it hard to go "back to sleep."

If a noise does not startle someone in Stage 1 sleep, he or she moves on to Stage 2 and Stage 3 of sleep. That movement takes him or her further towards a state of unconsciousness. Only after a sleeper leaves Stage 3 of sleep, does that sleeper initiate REM sleep. At that point the sleeper has begun to dream.