Sleep Debt and Its Effects
Most of us need about seven to nine hours of sleep each night for optimal functioning, but it’s probably no surprise that most of us get less than that. Every time we deprive ourselves of the rest we need, even if it is only a few minutes a day, that period of sleep loss accumulates into sleep debt. Eventually, that loss can overcome us, causing us to be irritable and lash out, act irrationally, make mistakes, perform poorly at school or work, or even fall asleep unexpectedly.
According to a series of studies described by Dr. Dement, we can avoid dangerously high sleep debt by adding back a relatively small amount of sleep to our normal routine. The evidence suggests that accumulated lost sleep must be paid back at some time, hour for hour, and those who have succeeded in lowering their sleep debt usually report gaining a new sense of well-being. “If you miss three hours one night, you must sleep 11 hours the next night (three plus your normal eight) in order to feel alert throughout the day,” writes Dr. Dement. While it may be difficult to pay it back in one lump sum, it is important to work at keeping your hours paid up, even if you do it just a few minutes at a time.
The long-term effects of sleep deprivation appear to be cumulative, so it is important to pay back sleep debt to avoid chronic health issues down the road. In addition to the obvious negative effects on alertness and cognitive function, studies have shown that sleep loss may speed up some aspects of aging and alter hormone levels. Sleep-deprived individuals have been found to have higher nighttime levels of the stress hormone cortisol and lower levels of thyroid-stimulating hormone, both of which are involved in regulating metabolism.
Other medical conditions potentially linked to chronic sleep deprivation are:
- A weakened immune system
- Heart disease
- Type-2 diabetes
Recent studies indicate that a chronic lack of sleep can lead to a deficiency of leptin, a hormone that controls appetite. Without adequate leptin levels, we tend to crave carbohydrates—even after eating—which can lead to overeating and contribute to obesity.
The Role of Hormones
Many different hormones are linked to or related to sleep; when their levels change or fluctuate, sleep is often affected. A hormone deficiency or imbalance can contribute to exhaustion and waking up feeling tired, among other symptoms. According to Dr. Thierry Hertoghe in his book The Hormone Solution, “correcting hormonal deficiencies can restore the days of sound, refreshing sleep” for many people. Key hormones include:
- Melatonin, known as the “hormone of darkness,” is produced at night by the pineal gland and is the major hormone that regulates and promotes good sleep. Melatonin lowers body temperature and this function may be why it has such a significant effect. A decrease in melatonin levels, such as is found in women with PMS, can lead to trouble falling asleep, falling back asleep after waking up or experiencing anxious or agitated sleep.
- Human Growth Hormone (HGH), which is secreted by the pituitary gland, is needed throughout life for growth, development, and repair of body tissues. It is secreted early in the night, at the onset of sleep, and a deficiency in growth hormone can lead to the same symptoms as described for melatonin deficiency.
- Cortisol stimulates the type of slow-wave, restorative sleep found in stages 3 and 4, as well as the production of growth hormone. Cortisol levels typically rise in the late morning and early afternoon and then decrease in the evening. A deficiency in this hormone can leave you feeling unrefreshed upon awakening, even if you have slept through the night because its purpose during sleep is to mobilize energy stores for the coming day.
- Thyroid Hormones have also been shown to improve sleep quality. In addition to causing the same symptoms as described for melatonin, HGH, and cortisol, a deficiency in thyroid hormones may cause waking up with a swollen face and puffy eyelids.
- Estrogens regulate the production of many of the key hormones that are secreted when we sleep, including melatonin, HGH, and cortisol, so changes in estrogen levels may profoundly affect sleep. Estrogens are believed to play a role in enhancing REM and, as their levels decline, REM may be frequently disrupted, leading to exhaustion.
- Progesterone appears to reduce the amount of time it takes to fall asleep, as well as the number of wakeful disruptions after succumbing to sleep. Studies suggest that progesterone has a calming and sometimes sedative effect. A deficiency in progesterone may lead to trouble falling asleep.
- Testosterone’s role in sleep is not as well understood, but the AASM reports that women are twice as likely as men to have sleep problems, which may reinforce that it does play a significant role. Like many of the other sex hormones, a testosterone deficiency has been linked to feelings of fatigue despite sleeping through the night.
Women and Sleep
The powerful role that hormones play helps us understand why so many women have difficulty falling or staying asleep, especially during times when their hormones are fluctuating.
The National Sleep Foundation’s Sleep in America poll surveyed over 1,000 women and the results suggest that the biological conditions unique to women (i.e., menstruation, pregnancy, and menopause) affect sleep quality. The poll found that nearly 70% of the women surveyed had trouble sleeping at least a few nights per week, with almost 50% reporting having trouble sleeping every night or nearly every night. The resulting sleep deprivation can lead to daytime fatigue, irritability, brain fog, increased anxiety, and depression, among other conditions.
For many women, pregnancy is the first time in their lives when they notice a real change in their ability to sleep. Some may be quick to blame the problem on the discomfort associated with the growing fetus’ movements, but the hormonal changes that accompany pregnancy are more likely the culprits. Sleep researcher Dr. Kathryn Lee found that pregnant women’s sleep becomes disrupted as early as 11 weeks into pregnancy. One of the most common complaints is the need to make more frequent trips to the bathroom throughout the night, even before the expanding uterus begins to press on the bladder. This feeling of the “need to go” is more likely caused at this stage of pregnancy by the increased level of progesterone, which inhibits the contraction of the smooth muscles of the urethra and bladder walls.
A woman’s menstrual cycle may also have an effect, but those effects may be very different for different women. Some women report sleep disturbances due to bloating, cramping, and headaches the week prior to their menstrual flow, while others experience them during their period. The hormonal changes in women with premenstrual syndrome (PMS) include a decrease in melatonin, which when combined with the other discomforts of the menstrual cycle, can add to their sleep troubles.
Sleep disruptions are some of the most common symptoms of perimenopause, and restful sleep eludes many menopausal women for a variety of reasons. In fact, Dr. Walsleben reports that nearly two-thirds of women complain of insomnia during the years leading up to menopause. In The Pause, Dr. Lonnie Barbach reports that “A lack of sustained sleep is the pattern we see with menopause. Women seem to wake up repeatedly during the night because they need to urinate or have a hot flash or night sweat, or for no apparent reason at all.” This is especially true of women who are particularly sensitive to fluctuations in estrogen levels, which can cause bothersome symptoms that interfere with getting a good night’s sleep.
Because estrogens may enhance and increase the time spent in the REM stage and reduce the time it takes to get to that stage, researchers designed studies to determine the effects of estrogen therapy. Placebo-controlled studies involving pre- and post-menopausal women found that estrogen therapy helps women to fall asleep faster, decreases wakefulness after falling asleep, and increases total sleep time.
In the post-menopausal years, women frequently report different sleep problems, including sleep-disordered breathing or loud snoring, which leave them feeling fatigued during the day. According to the AASM, this “may be related to falling progesterone levels, since younger women who experience surgical menopause are also at increased risk of developing sleep-disordered breathing.”
Especially for women, changing hormone levels are almost always at the root of their sleep problems and represent the biggest obstacle to enjoying an uninterrupted night’s sleep. Understanding the hormonal effects, along with addressing environmental factors and lifestyle habits, may be the key to helping women get a good night’s sleep.
Of course, factors other than hormones can be disruptive to your sleep. Problems often begin to occur during young adulthood or middle age due to increased responsibilities and stress, or life changes such as a new baby or job, or the aging process. While it helps to honestly analyze if any of these may be affecting your sleep, it is also important to realize that there are serious medical conditions that may be the cause of these disruptions.
Some of the more common sleep disorders include:
- Breathing interruptions, which range from those that are subtle enough that they do not wake us but are enough to disrupt our transitions into a deeper sleep, to obstructive sleep apnea, in which the throat muscles relax so much that our breathing is impaired. Snoring (especially loud, gasping snoring) is a common symptom of sleep apnea. Depending on the severity, these breathing disorders can cause a drop in oxygen levels during sleep, which can lead to or worsen other medical conditions, such as hypertension, stroke, and heart disease.
- Narcolepsy, which appears to be hereditary, is a dangerous, debilitating disease characterized by uncontrollable urges to sleep during waking hours. Narcoleptic attacks may occur at any time, and those who suffer from them may also hallucinate, have nightmares, or endure sleep paralysis while in a narcoleptic episode.
- Restless leg syndrome (RLS) is characterized by a burning or itching sensation on the legs that result in twitching, tossing, and turning throughout the night. Relief often requires getting up out of bed and walking around until the sensation subsides.
Most often, the disorders mentioned above can be effectively treated. Insomnia and depression are two more common disorders that are less straightforward to treat, and they are often related, as depression may be the underlying cause of insomnia.
Insomnia is considered the “common cold” of sleep problems, affecting approximately one-third of American adults. It is the most common sleep problem among women; according to the Sleep in America Poll, more than 60% of the women respondents reported experiencing insomnia within the previous month.
Effective insomnia treatment relies on identifying the underlying cause(s). The cause may be something serious such as depression; since sleep and mood involve many of the same chemical messengers and hormones, the chemical changes that induce feelings of depression might affect sleep as well. Insomnia may also be caused by stress and a hormone imbalance, as mentioned throughout this newsletter.
Whatever the cause, if any of these disruptions are affecting your quality of life, it is important to consult with a healthcare practitioner, especially if you think you may have a hormone imbalance or other medical problems.
The ability to fall asleep, stay asleep, and wake up feeling refreshed seems simple when it happens with little effort, and we tend to take it for granted when it happens so easily. However, we really begin to appreciate how critical sleep is to our overall health and well-being when it becomes problematic. Important factors in getting a good night’s sleep include:
- Eat and drink right. Simple diet and nutrition strategies may help improve your sleep habits, but most important is that you restrict what you eat and drink starting 3-4 hours before bedtime. Sleep experts and health practitioners recommend keeping dinner on the light side by avoiding protein-dense, fatty, spicy, or raw foods. Overeating at bedtime can lead to indigestion and a restless night.
- Avoid nicotine, caffeine, and alcoholic beverages within 4 to 6 hours of bedtime. Alcohol can also interfere with hormone secretion during sleep and negatively impact your natural rhythm.
- Exercise regularly, but early in the day. Another unanimous tip: get regular physical exercise, but avoid vigorous or strenuous activity within three hours of bedtime. While exercise generally helps us relax, exercising too close to bedtime will delay the time it takes for your body to unwind and fall asleep. The hormones and chemicals generated by exercising will increase alertness. Yoga and stretching, on the other hand, are better nighttime activities because they relax you. Taking a nice warm bath following yoga or stretching can also help set the right tone and promote better sleep.
- Establish a bedtime routine. Getting to bed with a conscious intention to sleep, and waking up at about the same time each day helps establish a routine for good sleep habits. If necessary, set your alarm and try to sleep the same number of hours each night. Avoid daytime naps, unless you are overcome with drowsiness or they are a regular part of your sleep routine; limit napping to one hour or less, and finish before mid-afternoon. One of the keys to establishing a bedtime routine is keeping your sleep environment comfortable and primed for sleep: your bedroom should be quiet, cool, and dark, and your bed should be used only for sex and sleeping. Reading or listening to soft music in bed can also help you unwind. If you do not fall asleep within about 15 to 30 minutes after lights out, get up for a few minutes, and try your bedtime routine again. Avoid bright lights, demanding tasks, or strenuous activity before getting back into bed.
- Maintain optimum hormone balance. When sleep problems appear to be linked to hormones, it is important to take appropriate action. There are ways of soothing the hormone-related symptoms that can interfere with good sleep (cutting down on salt, caffeine, and alcohol to reduce bloating during PMS, for example), but the best solution may be hormone therapy. Always consult with a licensed healthcare practitioner to analyze your hormone levels and find the hormone solution that is right for you.