We all could use a good night’s sleep. Sleep is an important part of the day but approximately one third of Americans do not get adequate sleep. Not getting a good night’s sleep is a health hazard and can lead to hypertension (high blood pressure), heart artery disease, atrial fibrillation (an irregular heart rhythm) and early death. What can be done to get a good night’s sleep?
First, we should understand a little about the physiology of sleep. The normal sleep cycle consists of four stages. There are three stages of non-REM (rapid eye movement) sleep, each lasting about five to fifteen minutes. Stage 3 of non-REM is the deep sleep stage where the body repairs itself. During this stage, the muscles, the tissues of the body and the brain are refreshed from the stresses of the day. In addition, bone and muscle are built and the immune system is strengthened. During the REM stage, the eyes move rapidly from side to side, the muscles are often paralyzed and the brain is more active than in stage 3. Dreaming occurs during REM sleep and a person can dream 4 to 6 times per night.
There are a variety of sleep disorders; the most common are insomnia and sleep apnea. Insomnia is difficulty falling asleep and staying asleep. It may be due to psychological stress, excessive mental activity at bedtime, inconsistent bedtimes or caffeine or heavy alcohol intake in the evening. It may be treated through behavioral modifications (for example keeping a regular bedtime), exercise (at any time of the day), and avoiding stimulants in the evening. Medications can be helpful, including sleeping pills and melatonin. Melatonin is a hormone produced by the pineal gland in the brain and it helps regulate the sleep-wake cycle. It is also available as an over the counter medication used to shorten the time to sleep. Nowadays, one of the biggest causes of insomnia is the use of light emitting electronic devices (laptop computers, tablets, cell phones and televisions) near bedtime. It has been found that the light exposure from these devices affects the normal sleep cycle. The light emitted suppresses the secretion of melatonin. This causes a later sleep time, increased alertness at bedtime, reduced REM sleep, and increased morning sleepiness. This effect is especially pronounced in children and adolescents. For a better night of sleep try to avoid using these devices for at least one hour prior to bedtime.
Sleep apnea is a condition characterized by periods of decreased breathing while sleeping (apnea means absence of breathing). Obstructive sleep apnea occurs when the upper airway collapses, air movement into the lungs ceases causing the oxygen level in the body to fall. This prompts the person to wake up and take deep breaths. These periods of apnea disrupt the sleep cycle and prevent the person from getting enough time in the deep sleep, restorative stages of sleep. Because the body does not get enough rest, the person feels “revved up” all the time. Sleep apnea is often seen in obese patients and is quite common occurring in 34% of men and 17% of women. It is associated with loud snoring, excessive daytime sleepiness, morning headaches and irritability. Sleep apnea is also associated with significant heart problems including hypertension (especially hypertension that is difficult to treat), stroke, heart failure, blockage in the heart arteries and atrial fibrillation. It is diagnosed by a sleep study, which counts and measures the periods of apnea and low oxygen. Treatment of sleep apnea primarily involves weight loss and CPAP (continuous positive airway pressure- a mask that keeps the airway open). Treatment with CPAP is especially useful in lowering blood pressure and preventing recurrent episodes of atrial fibrillation and congestive heart failure.
Just as important as sleep is the process of waking up. Being jolted from a deep sleep by an alarm clock is as bad as not getting enough sleep. When one is woken suddenly and too early, there is a prolonged period between the eyes opening and being fully awake. This phenomenon is called sleep inertia, a groggy sensation somewhat like jet lag. We feel this because we are awake, but our bodies want to keep sleeping. This is because the brain’s arousal system is activated almost immediately but the higher centers of the brain take longer to awaken. If woken abruptly, as with an alarm clock, the sleep inertia is more severe. Sleep inertia can take anywhere from two to four hours to resolve. Waking up naturally, by our own internal clock, is much better for us. The mismatch between our biologically optimal wake up time and the alarm clock time takes a toll on our system, leading to obesity, diabetes and heart disease. On the other hand, in cultures known for their longevity, there are a higher percentage of people who wake naturally.
This leads to the question, how much sleep is enough sleep? What is the optimal amount of sleep needed for a long and healthy life? In one study examining patients between 40 and 54 years old and who were free of heart disease, those sleeping less than 6 hours or more than 8 hours per night had higher risk of plaque in the heart arteries than those sleeping 7 to 8 hours. In another study of patients over 60 years old, those who slept less than 6 hours had a 12% increased risk for death and those who slept more than 9 hours had a 30% increased risk of death. In this population as well, 7 to 8 hours was the optimal amount of sleep time. However, very different results could be found if younger populations are studied.
So start altering those bad nighttime habits and start getting a good night’s sleep.
