We spend approximately a third of our lives sleeping. Why? Because our bodies need sleep to function during waking hours. Sleep, like nutrition and physical activity, is critical to our health, and when we don’t get enough, we sacrifice more than just a good night’s sleep.
Why Is Sleep So Important?
We sleep to restore brain chemicals and rest the body. Some researchers believe that the brain organizes and stores memories during sleep. Lack of sleep can affect our daytime functioning, hormonal balance, appetite, and immune system. Sleep plays a vital role in good health and well-being throughout your life. Getting enough quality sleep at the right times can help protect your mental health, physical health, quality of life, and safety.
The way you feel while you’re awake depends in part on what happens while you’re sleeping. During sleep, your body is working to support healthy brain function and maintain your physical health.
The damage from sleep deficiency can occur in an instant (such as a car crash), or it can harm you over time. For example, ongoing sleep deficiency can raise your risk for some chronic health problems. It also can affect how well you think, react, work, learn, and get along with others.
Sleep helps your brain work properly. While you’re sleeping, your brain is preparing for the next day. It’s forming new pathways to help you learn and remember information.
Studies show that a good night’s sleep improves learning. Whether you’re learning math, how to play the piano, how to perfect your golf swing, or how to drive a car, sleep helps enhance your learning and problem-solving skills. Sleep also helps you pay attention, make decisions, and be creative.
Sleep plays an important role in your physical health. For example, sleep is involved in healing and repair of your heart and blood vessels. Ongoing sleep deficiency is linked to an increased risk of heart disease, kidney disease, high blood pressure, diabetes, and stroke.
Sleep deficiency also increases the risk of obesity. For example, one study of teenagers showed that with each hour of sleep lost, the odds of becoming obese went up. Sleep deficiency increases the risk of obesity in other age groups as well.
Your immune system relies on sleep to stay healthy. This system defends your body against foreign or harmful substances. Ongoing sleep deficiency can change the way in which your immune system responds. For example, if you’re sleep deficient, you may have trouble fighting common infections.
Getting enough quality sleep at the right times helps you function well throughout the day. People who are sleep deficient are less productive at work and school. They take longer to finish tasks, have a slower reaction time, and make more mistakes.
How Much Sleep Is Enough?
The amount of sleep you need each day will change over the course of your life. Although sleep needs vary from person to person and it depends on your age:
- Babies: 16 hours per day
- Children: 9-16 hours per day
- Teenagers: 9 hours per day
- Adults: most need 7-8 hours, but some may need as few as 5 or as many as 10
- Pregnant women may need more sleep than usual
- Older adults may sleep for shorter periods of time, more often.
The current best estimates for the ideal amount of sleep are between seven and nine hours. Under six hours a night is linked to significant health issues and conversely, going over nine hours regularly also increases the risk of heart disease, diabetes and other problems.
Going to bed earlier seems to be better as your cortisol levels are normally at their lowest by 11pm and it’s easiest to get to sleep before then. You actually want to be already in bed and asleep by this time to benefit from this natural rhythm of your body’s chemistry.
Ideally, go to bed around the same time and wake up without an alarm clock in the morning. Once you get into a good rhythm this will happen naturally, but until then you might want to set it as a backup for work, but try and get up naturally without it if you can.
Just a week or two of better sleep can make a massive difference to so many different elements of your life. Isn’t that worth skipping the late night TV repeats and waking up early enough to start off your day with plenty of time and relaxed? I think you’ll like the difference.
Some people nap as a way to deal with sleepiness. Naps may provide a short-term boost in alertness and performance. However, napping doesn’t provide all of the other benefits of night-time sleep. Thus, you can’t really make up for lost sleep.
Sleeping when your body is ready to sleep also is very important. Sleep deficiency can affect people even when they sleep the total number of hours recommended for their age group.
What is good sleep?
Good sleep is restful and uninterrupted. Your muscles are relaxed. Your body rearranges itself once or twice each hour so your blood circulates. Sleep flows in five wave-like stages, often back and forth, throughout the night. You go through these five sleep stages several times. You spend at least two hours dreaming, during which your brain tries to make sense of random thoughts and brain signals. Your body’s cells produce and store proteins to renew and restore all of your systems.
The 5 Stages of Sleep
Stage one (10%) is light sleep, where your body relaxes and breathing slows. It’s common to drift in and out of this stage early in the night when you first go to bed. It’s easy to be awakened from this stage of sleep. You may experience slight muscle contractions that give you the sensation of falling.
In stage two (45-50%) your brain waves slow down, body temperature drops, breathing and heart rate remain constant and your eye movements stop.
Stages three and four (20%) You enter deep sleep. Stage three is characterized by very slow delta brain waves, with the occasional faster waves, while stage four is almost exclusively delta brain waves. There isn’t any eye or body movement in these later deep sleep stages and it is difficult to wake someone from this state (it’s also quite disorientating for them and should only be done in emergencies). These deep sleep stages are where your body is repaired and important physiological processes take place. However, the fifth stage of sleep appears to be more to do with your mind.
Independent of and quite different to these first four stages is REM sleep (20-25%), characterized by the rapid eye movements that it is named after. During the REM stage your breathing becomes more shallow and irregular. Heart rate increases, your blood pressure rises, males get erections, and you lose some ability to regulate your body temperature. This is primarily where you do most of your dreaming.
As the night goes on, periods of REM sleep increase in length while deep sleep time decreases. If you’re deprived of REM sleep one night, you may go into it earlier the following night to catch up. You really need your REM sleep if you want to feel your best the next day. Since REM happens at the end of a sleep cycle, getting only a few hours of rest in a night can mean we miss out on this vital phase.