Sleep, say researchers, is a required bodily function that addresses basic health needs, optimizes health, can affect hormone levels and mood as well as weight. Sleep is typically triggered by hormones that take their cues from the environment or our bodies. Sleep is a restorative process that helps us create memories and enhances learning as the pathways for these are very active during sleep. It also helps produce hormones that help build muscle mass, affects how the body burns energy, helps with cell repair and fights infections.
There are five stages of sleep. Four of them are 80 percent of sleep time, and stage five, aka REM state, takes up the remaining 20 percent as the dream state.
Stage one is a transition state between sleep and wakefulness. State two, which is 50 percent of all sleep time, is characterized by a slowing of breathing and heartbeat. Stages three and four, also called the Delta stages, are recognized by slow breathing and heartbeat. This state leads to stage five, or REM, rapid eye movement and is the deepest of all stages. This is when you experience dreams, and it is characterized by irregular heartbeat and breathing, and involuntary muscle jerks. REM periods can last from five minutes to more than an hour.
Normally, there is a cycling between these five stages of sleep but sleep disturbances do just that -- to the detriment of physical and mental health.
These disturbances disrupt normal cycles of sleep leaving you feeling fatigued, with problems concentrating or paying attention the next day. Consequently, the risk of car wrecks and workplace accidents increases.