Diet Promoting a Good Night's Rest

Sleep is a state of activity that occurs periodically and spontaneously, and during which the perception of external signals is interrupted and no active tasks are performed. It is a behavior that isolates oneself from the environment. It is a natural necessity of the human being and takes up about 1/3 of his life. Currently, the standard amount of sleep per week is only 6-6.5 hours per day. Limiting sleep to 6 hours for 4 days affects cognitive functions, performance, mood, glucose metabolism, appetite regulation, and immune function. It is recommended that adults should sleep 7–9 hours per day and teenagers 8.5–9.5 hours per day. From the perspective of sleep physiology, we can divide sleep into two phases: REM and NREM. The REM phase is associated with the occurrence of dreams, while the NREM phase is deep sleep, during which the body rests. Standard nighttime sleep consists of cyclical changes in NREM and REM phases, which repeat 4–5 times per night every 90 minutes. After each cycle, sleep usually becomes lighter and there are short-term awakenings. In the following cycles, the NREM phase shortens, while the REM phase lengthens. Sleep during the first three cycles covers more than 90% of the need for deep sleep. It is important to note that the cyclical phase changes of sleep depend on the mutual influence of serotonergic and noradrenergic neurons, called REM-off (not active in the REM phase), and cholinergic REM-on neurons (active in the REM phase). In addition to the neurotransmitters mentioned above, we can also distinguish several others related to the sleep cycle, such as 5-HT, gamma-aminobutyric acid (GABA), orexin, melatonin, galanin, norepinephrine, and histamine. Some nutritional interventions can affect the functioning of the mentioned neurotransmitters and thus also the quality of sleep.