The rhythm of waking and sleeping can be compared with the rhythm of activity and rest. During the phases of waking and power we consume more vital energy. Especially the cardiovascular system as well as the respiratory organs are very active and our muscles are having an increased tension (muscle tone). During the phases of sleep and recreation we regain new strength. Controlled by the vegetative nervous system (Vagus), the organism switches to regeneration. This phase is characterized by a certain brain-activity (Alpha waves) as well as by the activity of our digestive organs.
Especially after a lavish meal one should either rest or go for a walk. Because, in the gastrointestinal tract the food components get broken down, nutrients are extracted and processed by the body. These tasks are quite using the body’s capacity, at the same time the flow of the blood gets redirected into the gastrointestinal tract, for the most part. Both effects result in feeling tired and less able to concentrate after eating. Time for a nap! But, if you only took a light meal you are safe to talk a walk.
Respect BRAC-breaks or the Rest-Activity-Cycle
Our body has a biological basic rhythm of about 90 to 100 minutes between activity and rest. A finding of the German sleep medic and chronobiologist Prof. Dr. Karl Hecht is very interesting. Namely, he proved with measuring that we exactly follow this cycle during daytime, too. A healthy organism is giving us signals for when it is time to take a recreational break: onset of tiredness, decrease of motivation or concentration, for example.
When you dispense with the so-called BRAC-breaks (= Basic Rest Activity Cycle) although feeling exhausted on a longer-term, functional disturbances of body, mind and soul up to psychosomatic diseases occur. And the bad, non-recreational sleep is following hard on.
Generally speaking, if you keep on living against your inner cycle by forcing yourself to performance during phases of rest or sleep and force yourself to sleep during phases of power you will sooner or later create a classical sleep disturbance.