All About Sleep

Sleep is important for both mental and physical health. With it our productivity increases, our recovery time is shorter, our immune system is boosted and our mood improves. Everyone can benefit from better sleeping habits, although not everyone is aware of the various ways that sleep hygiene can be improved. That's the topic of today's post, so read on.

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THE STAGES OF SLEEP

First, let's run through the stages of sleep. There are five total*. Stages 1-4 are non-REM sleep; stage 5 is REM.

*The sleep profession in the US eliminated the use of stage 4 in 2008; stages 3 and 4 are considered stage 3 or N3.

Stage 1 is light sleep when you drift in and out and can be awakened easily. Your eyes move slowly and muscle activity slows down. It is during this stage that you may have sudden muscle contractions (twitches) or experience the sensation of falling.

Stage 2 is when your eyes stop moving and brain waves slow down for the most part, with occasional bursts of rapidity. Your body temperature drops slightly and your heart rate slows down.

Stage 3 is when delta waves (very slow brain waves) are interspersed with smaller, faster waves. This is considered deep sleep and is the point where people may experience parasomnias (abnormalities or undesirable behaviors while sleeping) such as sleepwalking, night terrors, talking in one's sleep and bedwetting.

Stage 4 continues deep sleep, but the brain produces almost exclusively delta waves. People awakened from this stage feel disoriented for a few minutes.

Stage 5 is the stage where you experience REM (rapid eye movement). Brain waves mimic activity during the waking state; the eyes remain closed but move quickly from side to side, possibly related to the dreams and brain activity during this stage. 

Progressing through all five stages is considered one sleep cycle. The first sleep cycle takes approximately 90 minutes; after that, they average between 100-120 minutes per cycle. Typically, you will go through 4-5 sleep cycles each night.

Deep sleep (stages 3 and 4) provide the most restorative sleep. This is why if you take a short nap during the day you can still sleep at night, but taking a longer nap which allows you to fall into deep sleep will result in you having trouble going to bed in the evening. 

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WHAT HAPPENS WHEN YOU SLEEP?

During deep sleep, ​human growth hormone is released and repairs and builds up your body and muscles from the stresses of the day. Your immune system​ strengthens itself. Your blood supply to the muscles regenerates and you experience an increase in new cell production. It is suspected that during REM, the brain refreshes itself for new learning the following day.  

When you sleep well you reduce your risk of heart disease and cancer. You reduce inflammation and lower stress and blood pressure. Sleeping improves memory and makes you more alert. It may reduce risk of depression and possibly help you lose weight as the hormones ghrelin and leptin, which regulate appetite, are disrupted by lack of sleep and insulin production increases with lack of sleep, leading to increased fat storage.

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WHAT IS SLEEP HYGIENE?

The term sleep hygiene refers to the rituals, behaviors, and norms that you follow near bedtime. Improving it is an easy way to help correct trouble sleeping and should be the first thing you adjust when this trouble arises. Sleep hygiene education is in fact an essential part of the cognitive-behavioral therapy used to treat insomnia.

Poor sleep hygiene includes behaviors such as regularly pulling all-nighters or sleeping in on the weekend to "make up" for lost sleep during the week. The opposite of any of the below tips will lead to less restful sleep.

Good sleep hygiene involves following a regular sleep schedule and avoiding stimulants in the early evening through lights out. See the below information for details of other positive bedtime habits.

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HOW MUCH SLEEP DO I NEED?

The very first thing you need to know is how much sleep you need. Our sleep needs change throughout our lives due to factors such as age and stress. As a general rule, adults require 7 - 7.5 hours of sleep. The National Sleep Foundation conducted a study regarding sleep duration and came up with this handy chart of average requirements:

Note that if you regularly sleep more or less than the recommended or 'may be appropriate' times, you may have a sleeping disorder and should consult a physician.

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WHEN SHOULD I SLEEP?

This question may seem like a given, but it actually isn't. In addition to varying work schedules, everyone has a different circadian rhythm. A circadian rhythm is a roughly 24-hour cycle in the physiological processes of all living creatures which determines their sleeping and eating patterns. There are clear patterns of brain wave activity, hormone production, cell regeneration and other biological activities linked to this cycle. Ever wonder why you're absolutely not a morning person but that chipper coworker of yours seems most alert before dawn? That's a difference in circadian rhythm.

A recent study by the University of Basel has shown that the mitochondrial network (the network of 'powerhouse' organelles within your cells) produces energy according to the circadian rhythm. If you are resting and working in sync with your rhythm, your energy production is boosted. If your actual sleep-wake cycles are out of tune with your internal clock, you will struggle to find the energy you need to perform your daily tasks. 

How do you suss out your circadian rhythm? It's pretty intuitive actually. Our alignment to our internal clock is called a chronotype which in layman's terms would translate to being a  "morning person" or "night owl." This chronotype is primarily a factor of genetics. Although it can change some over time according to age, overall it's something we're born with. There is actually a fancy wearable called the Oura ring which tracks your pulse, movement, body temperature etc and recommends an optimal sleep time. On the other hand, if you don't have money to burn you can keep notes on your wakefulness, energy levels and sleep patterns in a sleep journal to see what works best for you -- experimenting with different patterns (adding a short nap or taking a nap out, adjusting bedtime or wake-up alarm, etc) is another way to do the same time and best of all, it's free.

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STRATEGIES TO IMPROVE YOUR SLEEP

There are all sorts of ways to improve the quality and regularity of your sleep. Here's a list of ideas:

• Go to bed at the same time every night. Follow a regular sleep schedule which provides enough room for it to actually happen. Avoid bedtime procrastination at night -- it may be useful to set a notification on your phone for example to pop up as a warning so that you know it's time to wind down for the night.
• Wake up at the same time every day even when you have a bad night's rest with frequent awakenings. 
• Use a sleep tracker app or keep a sleep diary​ to check yourself and see if you're actually following the sleep schedule you set.
• Limit daytime naps to 30 minutes. Naps don't make up for inadequate nighttime sleep, but short naps of 20-30 minutes can help improve mood, alertness and performance.
• Avoiding stimulants such as caffeine and nicotine close to bedtime and alcohol in moderation -- it may help you go to sleep, but too much will interrupt the second half of the night as your body processes it.
• Exercising to promote quality sleep. As little as 10 minutes of aerobic exercise such as walking or cycling can improve nighttime sleep quality, but avoid strenuous workouts close to bedtime as often the body remains keyed up.
• Steer clear of foods which may cause indigestion close to bedtime. Proper energy balance (total calories in vs. calories expended during exercise and daily activity) has been linked to good sleep.
• Get adequate exposure to natural light and be sure your bedroom is illuminated with 'nighttime' incandescent bulbs rather than daylight bulbs.
• Establish a regular relaxing bedtime routine to help the body recognize that it is bedtime. A warm shower or bath, reading a book, meditation, or gentle yoga/stretches are all examples of things you may try closer to bed.
• Make sure the sleep environment is pleasant -- that your bed and pillows are comfortable and that the room is cool and dark. Items to consider include blackout curtains, sleep masks, ear plugs, 'white noise' machines, humidifiers, and fans.
• Dedicate your bed to sleep and sex and nothing else, because the psychological effect is important. Mentally and physically, lying down in your bed needs to signal rest. Watching TV in bed for example promotes a state of wakefulness and a mental anticipation of being awake 'just awhile longer' leading to bedtime procrastination.
• Limit screen time before bed including TV, phones, tablets, laptops and gaming devices. Although many electronic devices have screen color shifting options to convert the lighting to a nighttime spectrum automatically, the intensity of the light and the pings/vibrations of the notifications stress and/or excite your nervous system. Try to stop using all electronics 1 hour before bed; at the very least, use the nighttime spectrum and lower the intensity of the light.
• Stay calm when you can't sleep -- if after 20 minutes you haven't fallen asleep, leave your bedroom and do something relaxing somewhere else. If you mentally associate your bed with frustration it will key you up rather than allow you to unwind and rest.

If you have tried a combination of the above and still have trouble sleeping, you may have a sleep disorder or another health issue which complicates your rest. Keep a sleep diary and consult your doctor.

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CONSEQUENCES OF POOR SLEEP HYGIENE

An occasional sleepless night will make you tired and irritable the next day, but it won't harm your health. However, after several nights without proper sleep you may experience foggy thinking, making it difficult to concentrate and make decisions. You may fall asleep during the day (this is called microsleep), and will experience increasing levels of depression, moodiness, quick temper and/or being excessively emotional. You risk injury and accidents at home, work and on the road and this risk level rises the longer you continue with poor sleep habits. Long-term sleeplessness will affect your overall health, weakening your immune system. Your sex drive lowers, and your balance and coordination suffer.

A lack of sleep may also trigger mania in people who have manic depression. Sleep deprivation prompts your body to release higher levels of insulin after you eat. Insulin controls your blood sugar level and higher insulin levels promote fat storage and increase your risk for diabetes as well as obesity. 

Sleep affects processes which keep your heart and blood vessels health, including your blood sugar, blood pressure and inflammation levels. It also plays a vital role in the body's ability to heal and repair the blood vessels and heart. Studies show that people who don't sleep enough are more likely to have cardiovascular disease including heart attack, stroke, and high blood pressure.

As mentioned previously, human growth hormone is released during deep sleep. These hormones build muscle mass and repair cells and tissues. For testosterone production you need at least three hours of uninterrupted sleep. If you are not sleeping enough, you are also compromising the benefits of your fitness regimen as it is during rest that your body builds itself.