Sleep is part of the daily routine, but most people find it difficult to sleep properly at some point in their lives, also known as insomnia. It usually lasts a short period, perhaps when the individual is worried, nervous, or stressed. When these situations disappear, you go back to sleeping normally. However, if the individual cannot return to sleep well, it can be a real problem because sleep keeps our minds and bodies healthy.
What is sleep?
Sleep is the regular period in every 24 hours during which we are unconscious and unaware of our surroundings. There are two main types of sleep:
• REM sleep (Rapid Eye Movement): It comes and goes throughout the night, and constitutes a fifth of our sleep. The brain is very active, our eyes move quickly from side to side and we sleep, but our muscles are very relaxed.
• Non-REM sleep: The brain is quiet, but the body can move. Hormones are released into the blood, and the body is repaired after the day's wear and tear.
There are four stages of non-REM sleep:
1. "Pre-sleep": the muscles relax, the heart beats more slowly, and the body temperature drops.
2. "Light sleep": the individual can be easily awakened without feeling confused.
3. "Slow wave sleep": the blood pressure falls, the individual can talk or walk asleep.
4. "Slow and deep wave sleep ": during this time, it is very difficult to wake up, if someone wakes you up, you will feel confused.
Sleep is a biological necessity that allows restoring the physical and psychological functions essential for a full performance. Sleep and wakefulness are brain functions and, therefore, are subject to alterations of the nervous system. Sleep is neither a passive situation nor a lack of vigil, but an active state in which changes occur in bodily functions, in addition to mental activities of great importance for the physical and psychological balance of individuals. During sleep, hormonal, biochemical, metabolic, and temperature changes are necessary for the proper functioning of the human being during the day.
Sleeping adequately allows the release of oxytocin during non-REM sleep. It has been proven that this hormone helps relieve anxiety, increases confidence, and reduces social fear. Along with serotonin (a neurotransmitter released during sleep), oxytocin increases the feelings of love, empathy, and connection with other individuals due to its activity in the 5-HT1A receptors. Furthermore, maintaining adequate sleep hours generates an increase in serotonin concentrations in the brain which has been linked to the treatment of mental disorders such as depression.
Sleep also releases dopamine, the neurotransmitter widely known as being responsible for the sensation of pleasure. However, the latest findings show that its main function could be motivation since it was shown that people more focused on meeting certain demanding goals were those with the highest concentration of dopamine in the prefrontal cortex and the striatum.
How much sleep do we need?
This depends mainly on your age.
• Babies sleep about 17 hours a day.
• Older children only need 9 or 10 hours each night.
• Most adults need about 8 hours of sleep each night.
• Older people need the same amount of sleep, but usually have only one period of deep sleep at night, usually in the first 3 or 4 hours. After that, they wake up more easily. We also tend to dream less as we get older.
There are differences between people of the same age. Most of us need 8 hours per night, but some people (few) manage with only 3 hours per night. However, this can have serious consequences in the future.
Sleep disorders in adult life
You may feel that you do not get enough sleep or that even if you sleep the necessary hours, you do not get a good night's rest. There are many reasons for not sleeping well:
• The bedroom can be too noisy, hot, or cold
• The bed can be uncomfortable or too small
• Not having a regular sleep routine
• Not doing enough exercise
• Eat too late and find it difficult to go to sleep
• Tobacco, alcohol, and drinks that contain caffeine such as tea and coffee
Other more serious reasons include:
• Emotional problems
• Anxiety and worries
• Depression: wakes up very early and cannot go back to sleep
What happens if I do not sleep well?
Scientific studies increasingly give evidence that not sleeping well can affect our daily lives and our health. There are multiple consequences, both physical and psychological when we fail to have a restful sleep.
According to experts, a person must sleep between 8 hours a day to maintain an optimal physical, emotional, and mental state. However, the changes in the lifestyle of today have made the quality of sleep and the ideal time to rest much worse.
Studies have shown the negative health effects of restricting nighttime sleep. The results indicate that short periods of sleep have a negative impact on carbohydrate metabolism and endocrine function. Both factors are considered fundamental parts of the normal aging process, so if the habit of shortening sleep periods persisted in the organism, the severity of the chronic disorders associated with aging would increase.
Multiple studies showed a marked increase in glucose concentrations, which predisposes to metabolic diseases and increases the risk of obesity. The sympathetic nervous system also suffered negative alterations, increasing adrenergic activity and consequently, plasma levels of adrenaline and cortisol which is widely related to cardiovascular diseases such as hypertension, arteriosclerosis, ischemic heart disease, among others.
In a study published by Harvard Health Publications, it was evidenced that with sleep deprivation, patients presented deterioration of verbal fluency, planning capacity, creativity and originality, slowing of reaction time, signs of deactivation in the EEG, and drowsiness. The performance of long, repetitive and monotonous tasks is affected, especially in the case of newly acquired skills. Short-term memory impairments or reversible neuropsychological disorders may also appear in tasks involving the prefrontal cortex.
According to research conducted by the National Sleep Foundation of the United States, people who cannot sleep at least 6 hours a day, triple the risk of falling asleep at the wheel as a result of deterioration of mental coordination. The mood can also be affected, with a slight increase in anxiety, depression, irritability, confusion, etc.
Also, sleep deprivation has immunosuppressive effects. The ability of lymphocytes to produce cytokines is negatively affected, and there is a decrease in the production of necrosis factor alpha tumors (TNF-alpha) and some interleukins, which predisposes to suffer infectious diseases, mainly those that affect the respiratory system. In fact, it was determined that those who slept less had a greater risk of dying at a young age compared to those who slept properly.
Other studies have indicated that sleep deprivation delays the recovery of the hypothalamic-pituitary-adrenal axis and produces alterations in glucocorticoid feedback. Thus, lack of sleep can decrease resistance to stress and accelerate the effects of glucocorticoid excess on metabolism and cognitive functions.