It’s the end of February and we’re closing out the series on heart health. Today I want to share with you some information about sleep. You may have been hearing more and more about sleeps importance lately in the news. Here is what I have been learning.
Sleep is an important part of our daily routine and spend about one-third of our time doing it. Quality sleep, and getting enough of it at the right times, is as essential us as food and water. Without sleep we can’t form or maintain the pathways in our brains that let us learn and create new memories, and it’s harder to concentrate and respond quickly.
Sleep is important to a number of brain functions, including how nerve cells (neurons) communicate with each other. In fact, our brain and body stay active while we sleep. Recent findings suggest that sleep plays a housekeeping role that removes toxins in our brains that build up while you are awake.
We need sleep, but its biological purpose remains a mystery. Sleep affects almost every type of tissue and system in our bodies – from the brain, heart, and lungs to metabolism, immune function, mood, and disease resistance. Research shows that a chronic lack of sleep, or getting poor quality sleep, increases the risk of disorders including high blood pressure, cardiovascular disease, diabetes, depression, and obesity.
There are two basic types of sleep: rapid eye movement (REM) sleep—the one we may think more about. And non-REM sleep (which has three different stages). Each is linked to specific brain waves and neuronal activity. We cycle through all stages of non-REM and REM sleep several times during a typical night, with increasingly longer, deeper REM periods occurring toward morning.
Stage 1 non-REM sleep is the period from being awake to sleep. During this short period (lasting several minutes) of relatively light sleep, our heartbeat, breathing, and eye movements slow, and our muscles relax with occasional twitches. Our brain waves begin to slow from their daytime wakefulness patterns.
Stage 2 non-REM sleep is a period of light sleep before you enter deeper sleep. Our heartbeat and breathing slow, and muscles relax even more. Our body temperature drops and eye movements stop. Brain wave activity slows but is marked by brief bursts of electrical activity. We spend more of our repeated sleep cycles in stage 2 sleep than in other sleep stages.
Stage 3 non-REM sleep is the period of deep sleep that we need to feel refreshed in the morning. It occurs in longer periods during the first half of the night. Our heartbeat and breathing slow to their lowest levels during sleep. Your muscles are relaxed and it may be difficult to awaken you. Brain waves become even slower.
REM sleep first occurs about 90 minutes after falling asleep. Our eyes move rapidly from side to side behind closed eyelids. Mixed frequency brain wave activity becomes closer to that seen when we’re awake. Our breathing becomes faster and irregular, and our heart rate and blood pressure increase to near waking levels. Most of our dreaming occurs during REM sleep, although some can also occur in non-REM sleep. Our arm and leg muscles become temporarily paralyzed, which prevents us from acting out our dreams. As we age, we sleep less of our time in REM sleep. Memory consolidation most likely requires both non-REM and REM sleep.
How much sleep do we need? Our need for sleep and our sleep patterns change as we age, but this varies significantly across people of the same age. There is no magic “number of sleep hours” that works for everybody of the same age. Babies initially sleep as much as 16 to 18 hours per day, which may boost growth and development (especially of the brain). School-age children and teens on average need about 9.5 hours of sleep per night. Most adults need 7-9 hours of sleep a night, but after age 60, nighttime sleep tends to be shorter, lighter, and interrupted by multiple awakenings. Elderly people are also more likely to take medications that interfere with sleep.
In general, people are getting less sleep than they need due to longer work hours and the availability of round-the-clock entertainment and other activities.
Many people feel they can "catch up" on missed sleep during the weekend but, depending on how sleep-deprived they are, sleeping longer on the weekends may not be adequate and may interrupt our ability to sleep well during the work week.
Getting enough sleep is good for our health. Here are a few tips to improve our sleep:
- Set a schedule – go to bed and wake up at the same time each day.
- Exercise 20 to 30 minutes a day but no later than a few hours before going to bed.
- Avoid caffeine and nicotine late in the day and alcoholic drinks before bed.
- Relax before bed – try a warm bath, reading, or another relaxing routine.
- Create a room for sleep – avoid bright lights and loud sounds, keep the room at a comfortable temperature, and don’t watch TV or have a computer in your bedroom.
- Don’t lie in bed awake. If you can’t get to sleep, do something else, like reading or listening to music, until you feel tired.
- See a doctor if you have a problem sleeping or if you feel unusually tired during the day. Most sleep disorders can be treated effectively.
This month we’ve discussed heart health including cardiovascular diseases and how they are different in women as well as how exercising, eating well and sleep may help you reduce your risk.