All animals sleep, strongly suggesting that the act of sleeping has some evolutionary benefit. Human beings spend approximately 1/3 of their lives—about 8 hours per night—sleeping. The true purpose of sleep, however, is poorly understood. Whether it’s for restoration, energy conservation, memory consolidation, or all three, sleep is more than just something we do at the end of the day. It’s one of the most important requirements for optimal health, and we must defend our ability to do it rigorously.
The American Academy of Sleep Medicine and Sleep Research Society recommend that adults aged 18-60 should sleep 7 or more hours per night on a regular basis, while the National Sleep Foundation specifies 7-9 hours for adults aged 18-64 and for adults over 65, 7-8 hours. Unfortunately, nearly 30% of adults report sleeping 6 or fewer hours per night. The rates of inadequate sleep are even higher among younger adults, racial and ethnic minorities, and people with low socioeconomic status.
We may often sacrifice our sleep in the short-term to study for a test or complete an important work project. As long as we give ourselves time to make up the “sleep debt” we accumulate as a result (say, by sleeping in on the weekend or taking naps) we shouldn’t suffer any significant adverse consequences. When we get inadequate sleep on a chronic basis, however, we put ourselves at risk for serious negative consequences including:
- low energy (mild sleep deprivation is often experienced as a dip in energy in the mid-afternoon)
- depression (sometimes we’re unable to distinguish between depression and simple fatigue)
- decreased ability to concentrate
- inability to maintain attention
- reduced motivation
Chronic sleep deprivation also been associated with obesity, cardiovascular disease, hypertension, and even premature death.
Here are some basic tips about obtaining good sleep:
- Stick to a sleep schedule of the same bedtime and wake up time, even on the weekends. Consistency makes it much easier to fall asleep and wake easily.
- Practice a bedtime routine. While this is rarely assessed formally in research studies, one study incorporated a routine of personal care, lights out, and reduced sources of noise up to two hours before the desired sleep time as part of a multiphase sleep treatment intervention that effectively improved duration of sleep for a cohort of nursing home patients.
- If you have trouble sleeping at night, avoid naps, especially in the late afternoon. However, short naps lasting approximately 20 minutes can help alleviate daytime fatigue, sleepiness, and even provide cognitive benefit. Nap duration over 30 minutes is more likely than shorter nap duration to produce sleep inertia, a period of reduced alertness and cognitive performance after waking.
- Naps are often necessary for shift workers to mitigate fatigue and improve alertness during work times.
- Exercise daily. In one study, regular exercise was shown to have small beneficial effects of total sleep duration, small-to-medium beneficial effects on ability to fall asleep faster, and moderate beneficial effects on sleep quality.
- Maintain a sleep environment conducive to sleep. The bedroom should be comfortably cool—for example between 60 and 67 degrees Fahrenheit. In population studies, nocturnal environmental light and noise significantly impact sleep quality and quantity. Use of blackout curtains, ear plugs, or sound machines may help promote an optimal sleep environment for individuals with sleep disruptions due to environmental stimuli.
- Sleep on a comfortable mattress and pillows.
- Regular bright light exposure in the mornings may help to maximize alertness and maintain a regular circadian rhythm. Studies in extreme latitudes where sunlight is minimal in the winter have found that an hour of exposure to white light in the morning helped subjects go to sleep earlier and wake earlier.
- Avoid cigarettes, caffeine, and heavy meals in the evening. While alcohol use does not seem to affect sleep duration, at least one study has reported that alcohol use (average 2.2 drinks per day) has a negative association with sleep quality.
- Wind down with quiet activities that may promote sleep, such as reading with a dim light. Avoid use of electronics at least 30 minutes before habitual bedtime and in the middle of the night if nocturnal awakenings occur. The blue light emitted from computer screens and hand-held devices can suppress natural melatonin production, resulting in difficulty falling asleep; however, the exact duration of use and intensity of lighting that cause this effect are variable in the literature.
- If you cannot sleep, do not look at a clock. Go into another room and do something relaxing until you feel drowsy enough to fall asleep again. Then return to bed.