There are two distinct stages of sleep: REM and non-REM. REM sleep alternates with non-REM sleep, a state of differing levels of brain activity. Non-REM sleep, or quiet sleep, has three distinct stages of progress. The first is known as rapid eye movement (REM), which occurs as a result of rapid brain waves. Non-REM sleep lasts for less than an hour and is characterized by a gradual decline in mental activity.

Slow-wave activity peaks in childhood, decreases with age, and eventually disappears altogether in adulthood. Sleep patterns in the elderly may be the result of brain structures that regulate sleep. REM sleep is typically more erratic, with fewer sleep cycles than in children. As you age, the amount of slow-wave activity declines and you become more likely to experience waking-assisted wakefulness. Sleeping patterns in older adults are characterized by a combination of the aforementioned factors.

While asleep, the brain releases proteins called cytokines, which help the immune system fight off infection and inflammation. These chemicals help the body fight off harmful germs and maintain emotional balance. During sleep, thousands of neurons in the brain switch from a waking to a sleeping state, sending signals to different parts of the body. Scientists also believe that sleep is essential for heart health. Studies have linked poor sleep with heart disease. The brain needs at least seven hours of sleep every night to maintain proper function.

Objective evidence: The objective observation of different phases of sleep allows us to determine which stages are more likely to occur. These stages can be ascribed to distinct phases based on their physiological, motor, and behavioral characteristics. Depending on the criteria, they may not be the same for everyone. While subjective criteria may be more useful for defining a specific state, they can still be at odds with objective measurements. In addition, sleep can also be categorized according to the duration of the time between awakening and falling asleep.

In humans, lack of sleep negatively affects growth and the immune system, both of which are vital for our health. Research has also shown that a lack of sleep can reduce our immune system’s ability to protect us from sickness. Researchers have been studying sleepwalking in marine mammals, which is a phenomenon in which half the brain is responsive. However, these observations raise questions about the human brain and its capacity. They also suggest that the purpose of sleep is unknown.

Another common disorder is periodic limb movement disorder (PLMD), which causes repeated awakenings and severe sleep fragmentation. Among older people, RLS and PLMD account for about a third of all cases of insomnia. Fortunately, drugs affecting dopamine can relieve many of these symptoms, but further research may lead to more effective therapies. A doctor can help you identify a sleep disorder before you begin feeling groggy. And don’t forget to seek treatment for your sleep disorder.