After an evening of staying up watching late-night TV or desperately trying to fall asleep without success, you’ll feel the effects of lack of sleep the following morning. Hitting the snooze button a few more times or yawning through your first meeting of the day, however, are only the immediate and superficial effects of sleep deprivation. Long term, chronic lack of sleep can do much more harm than just leaving you feeling tired. Quality rest is essential to staying healthy. It’s the time when your body works much of its restorative magic.
Soon after you drift off, your brain works overtime as a biochemical factory, churning out antioxidants, growth hormone, melatonin, DHEA and testosterone. All of this activity helps restore your body’s complex chemical balances, repairs and regenerates tissues, builds bone and muscle and strengthens your immune system.
Once that occurs, you shift into a sleep phase called rapid eye movement (REM), or dream stage, while your brain sorts through that day’s experiences, imprints memories, makes connections and consolidates learning. The last period of sleep, toward morning, is crucial for boosting your creativity and mood.
So, though it may not seem like much is happening while you’re resting contently, your body is busy doing some pretty important work.
How Sleep Deprivation Affects Your Health
While each person is different, most experts agree that adults need seven to nine hours of sleep at night. But the average American only gets about 6.9 hours, according to the National Sleep Foundation. For some people, a mere four or five hours of nightly rest is the norm. The effects of a lack of optimal sleep time can take many forms:
- Cognitive performance: When you log fewer than six hours of sleep, your memory and reaction time suffer in the same way they would after staying awake for up to 48 hours straight, according to a study from the University of Pennsylvania School of Medicine. This can have a big impact on things like driving safety, for example.
- Illness: You are more likely to catch a cold if you sleep fewer than seven hours per night. Experts think sleep helps regulate the body’s response to infection.
- Weight gain: You produce more of the appetite-promoting hormone ghrelin and less of the satiety-producing hormone leptin when you are sleep deprived.
- Mood disorders and depression: Studies have found that people who are severely sleep deprived report feeling stressed, sad, angry and mentally exhausted. All of these self-reported symptoms improved dramatically when the subjects returned to a normal sleep schedule.
- Type 2 diabetes: Being sleep deprived affects your body’s ability to regulate blood sugar levels, which may double your risk for type 2 diabetes, according to the journal Diabetes Care.
- Heart disease: People who sleep five or fewer hours a night are more likely to develop high blood pressure than are those who get more than six, possibly due to their elevated levels of the stress hormone cortisol, which strain the heart, according to a study in the journal Sleep. There’s also research indicating that people who get less than five hours of sleep have more plaque in their coronary arteries compared to those who get more than seven hours of sleep, which may also be related to higher cortisol levels.
What’s Getting in the Way of a Full Night’s Sleep
Technology, as wonderful as it is, is partly responsible for our lack of sleep. We used to go to bed soon after the sun went down and slept until it came up again. But since the invention of the electric light, we have been able to stay up long past sunset. (Your bed can have a hard time competing with the allure of 24-hour television and the Internet, too.)
Many of us want to clock adequate sleep time, but have a hard time drifting off, perhaps because of racing thoughts about the day, for example. If that’s you, you may be able to address your restlessness without medication.
Still others may be challenged by a chronic sleep disorder, which makes the effects of lack of sleep far more intense than they may be when you only experience occasional tossing and turning. At least 40 million Americans suffer from chronic sleep disorders like these, according to the National Institute of Neurological Disorders & Stroke:
- Insomnia: You may sleep too little, have difficulty falling asleep, awaken frequently throughout the night, or be unable to get back to sleep. Insomnia impairs the way you function in your daily life.
- Apnea: This condition causes multiple awakenings each night as a result of the temporary closing of your airway during sleep. Apnea not only prevents sound, restful sleep, but the repeated short episodes of oxygen deprivation can also raise your blood pressure and increase the risk of sudden death, stroke and heart attack.
- Sleep phase disorder: People with sleep phase disorder cannot fall asleep at their desired bedtime and find their sleep cycles are out of sync with daily life, despite trying lifestyle changes and medication.
- REM movement disorder: People with this neurological disorder will act out their dreams, often waking themselves in the process.
- Alcohol- and medication-related disorders: Some prescription drugs can disrupt your body’s natural sleep cycle. Although alcohol may initially help you fall asleep, it begins to stimulate the parts of the brain that cause arousal after just a few hours, in many cases causing awakenings and sleep problems later in the night.
- Narcolepsy: In this central nervous system disorder, the brain cannot control sleep-wake cycles. At various times throughout the day, people with narcolepsy experience sudden bouts of sleep, which can last from a few seconds to several minutes.
The effects of lack of sleep are very real and potentially harmful to your health. Give your body the sleep time it needs to do the best it can to keep you well. If you’ve tried to get the recommended amount of sleep without success, speak with your doctor for additional suggestions that address your specific obstacles.