WHY IS SLEEP IMPORTANT?
Sleep is not an optional extra in life, it is a fundamental requirement that far too many people overlook. Much of what we know about the importance of sleep comes from the experiences of people who have taken part in sleep-deprivation experiments. That is, where insufficient sleep, or no sleep, has been taken over successive 24-hour periods. The bottom line is that when people are sleep deprived they’re not able to function properly during the day.
“What is sleep for?”
Oh Karen, I thought you’d never ask... Sleep serves to ensure ‘good’ quality daytime functioning.
Sleep has its physical, mental and emotional processing components, so when we have had no sleep or insufficient sleep, these processes don’t work effectively. In physical terms we will feel lethargic and sleepy, mentally we become sluggish, we may experience poor concentration and lapses in memory, and emotionally we may become irritable, down, or have phases of excitable bursts of hyperactivity.
It’s perfectly normal to worry about the effects of lack of sleep, although the effects of sleep deprivation vary from person to person, we’re all negatively impacted following a night of insufficient, poor sleep- this begins to impact things like mood and emotional processing, pain thresholds, functioning of the immune system, glucose metabolism, and general physical performance.
THE DIFFERENT STAGES OF SLEEP:
Within sleep, two broadly-defined states exist: rapid-eye-movement (REM
) sleep and non-REM (NREM) sleep. Sleep is normally entered through NREM sleep. NREM sleep is traditionally made up of sleep stages 1,2,3, and 4, which are defined by changes in brain activity (measured using Electroencephalography [EEG]) and generally reflect increasing sleep depth as one progresses through to stage 4 (1)
. The brain alternates between NREM and REM sleep in what is termed a sleep cycle.
Sleep cycles tend to last approximately 90 minutes and ‘good’ sleepers, generally go through 4-5 sleep cycles in a given night. The composition of sleep cycles changes throughout the night, with the first third of the night tending to be characterized by greater amounts of slow-wave (deep) sleep (stages 3&4), whereas REM sleep tends to dominate in the latter third of the night
. Arousal threshold (the noise required to induce an awakening) also differs according to sleep stage. It’s known, for example, that subjects are hardest to wake from slow-wave sleep, reflecting greater intensity and depth of sleep
In NREM sleep, thought content is usually absent or, if present, fragmented but logical. In contrast, REM sleep tends to be characterized by vivid and often bizarre, illogical thought content, which is generated internally, or subconsciously
. REM sleep is the stage of sleep most often associated with dreaming, and where some regional brain areas are as metabolically active as during wakefulness. REM is also defined by phasic eye-movements and muscle atonia (paralysis)- because for some people that would be pretty disastrous if we’re able to act out our dreams.
The distribution of [average] time spent in specific sleep stages throughout the night is as follows:
Stage 1 (2-5%)
Stage 2 (45-55%)
Stage 3 (3-8%)
Stage 4 (10-15%)
REM sleep (20-25%)
DIVING INTO WHAT CAUSES SLEEP:
Sleep is regulated by homeostatic and circadian process. Together these two processes determine most aspects of sleep and are related to variables like sleepiness and alertness.
Sleep is an automatic process and therefore under our voluntary control. Whether awake or asleep we are at the mercy of two biological processes:
(1) Sleep Homeostasis, known as 'Sleep Pressure'
(2) The Circadian Rhythm, known as the 'Body Clock'
These two processes work in harmony to promote good consolidated sleep at night.
Sleep pressure can be thought of as the brain pressure and need for sleep, it usually becomes greater with increasing amounts of time spent awake. In this way, the ‘pressure’ to sleep is directly related to the amount of time that we have been awake (2) (3)
For example, when we wake-up in the morning after a good night's sleep, we will have a very low sleep pressure or a ’need to sleep'. As we continue throughout the day, sleep pressure will begin to accumulate (like an hourglass egg-timer). At the end of a full day, at bedtime, we will have a great amount of pressure to sleep. By going to bed and having another good night's sleep, then sleep pressure will be reset for the start of the next day.
The Circadian Rhythm (body clock)
is an internally generated biological rhythm that allows a number of processes to rise and fall over the twenty four hour period
. Many biological processes run in a Circadic type fashion whether that be digestion, peak cognition, performance, hormones, etc.
In a good sleeper, who is in-synch with the environment, the circadian rhythm will naturally rise in the early morning, promoting wakefulness and alertness – this is sometimes known as the alerting force. As the day continues, the circadian rhythm will promote wakefulness until it reaches a peak at about midday. After this time, the circadian rhythm will start to dip. This initial fall is known as the 'post lunch dip' (you may be familiar with greater feelings of sleepiness after lunch). Nearing the end of the day, around bedtime and sleep, the circadian rhythm drops to the lowest level and helps to maintain sleep. In this way, sleep pressure is very high, while the alerting effect of our body clock is low, creating the optimal opportunity to sleep
Melatonin is a naturally occurring hormone which the brain produces in the late evening and throughout the night (4)
. It is associated with the dark period of the light-dark cycle. Some studies suggest that melatonin in tablet form, several hours before bedtime, can help people get to sleep more quickly. However, again there are few long-term studies, so melatonin does not offer a solution for persistent poor sleep. Some people prefer the idea of a 'natural' product over a sleeping pill, but like sleeping pills, the benefits of melatonin seem to be lost almost immediately when people stop taking it.
Light at night may inhibit the production of melatonin and lead to a delay in sleep onset and possibly sleep fragmentation. There is a growing concern that adolescents (and adults) are being exposed to light from phones and computers, for example, when in bed late at night, can impact melatonin release and sleep-onset
The hormone melatonin is largely responsible for the regulation of the body clock throughout our lives. Melatonin is produced in the brain, in the pineal gland. It’s production rate is dictated by natural light, so that during hours of darkness (the normal sleep period) melatonin production increases, and as morning approaches and with the coming of daylight, melatonin production is once again shut down.
Lack of Sleep in Performance and Health
Research into how lack of sleep affects sports performance, further emphasizes the potential impact of sleep deprivation. Impairments to glucose metabolism may be problematic for athletes who rely on their energy supplies to perform optimally. In fact some research suggests that athletes may benefit from even more sleep than the average person, a recent study found that collegiate basketball players saw their performance improve significantly after sleeping for at least 10 hours (6)
Effects of sleep deprivation are ever expanding. A lack of sleep can impair the body's ability to fend off diseases and inflammation (7)
Chronic lack of sleep has also been linked to weight gain. A study by Spiegel et al. (2004) found that restricting sleep in 12 healthy men for two days, from 10 to 4 hours, resulted in a reduction in leptin (a hormone involved in feeling 'full' after eating) and elevations in ghrelin (hormone involved in stimulating feelings of hunger). These hormonal changes were also accompanied by self-reported increases in appetite and hunger (8)
THE FOUNDATIONAL IMPORTANCE OF SLEEP
Sleep disturbances can occur on their own, but in the vast majority of people poor sleep co-exists alongside mental and/or physical health problems. The traditional view was that poor sleep was simply secondary to these other issues and that by improving the so-called 'primary' illness, poor sleep would immediately resolve. Important research conducted in the last couple of decades has revealed a much more complex picture. It is now known, for example, that poor sleep on its own can be a risk factor for developing future illness, as well as exacerbating existing health conditions. Experimental studies with healthy good sleepers, where total sleep time is restricted, indicates that lack of sleep (or certain stages of sleep), negatively impacts next-day emotional processing and mood, pain thresholds, immune functioning and glucose metabolism. Thus, both 'mind and body' are affected by alterations to sleep.
Sleeping well directly affects your mental and physical health.
Fall short and it can take a serious toll on your daytime energy, productivity, emotional balance, and especially your body composition related goals. Now for the tips on improving your sleep. 🙂
Tip 1: Keep in sync with your body’s natural sleep-wake cycle
Getting in sync with your body’s natural sleep wake cycle, is one of the most important strategies for sleeping better. If you keep a regular sleep-wake schedule, you’ll feel much more refreshed and energized than if you sleep the same number of hours at different times, even if you only alter your sleep schedule by an hour or two.
Try to go to sleep and get up at the same time every day. This helps set your body’s internal clock and optimize the quality of your sleep. Choose a bed time when you normally feel tired, so that you don’t toss and turn. If you’re getting enough sleep, you should wake up naturally without an alarm. If you need an alarm clock, you may need an earlier bedtime.
Avoid sleeping in—even on weekends. The more your weekend/weekday sleep schedules differ, the worse the jetlag-like symptoms you’ll experience. If you need to make up for a late night, opt for a daytime nap rather than sleeping in. This allows you to pay off your sleep debt without disturbing your natural sleep-wake rhythm.
Be smart about napping. While napping is a good way to make up for lost sleep, if you have trouble falling asleep or staying asleep at night, napping can make things worse. Limit naps to 15 to 20 minutes in the early afternoon.
Fight after-dinner drowsiness. If you get sleepy way before your bedtime, get off the couch and do something mildly stimulating, such as washing the dishes, calling a friend, or getting clothes ready for the next day. If you give in to the drowsiness, you may wake up later in the night and have trouble getting back to sleep.
Tip 2: Control your exposure to light
Melatonin is a naturally occurring hormone controlled by light exposure that helps regulate your sleep-wake cycle. Your brain secretes more melatonin when it’s dark—making you sleepy—and less when it’s light—making you more alert. However, many aspects of modern life can alter your body’s production of melatonin and shift your circadian rhythm.
How to influence your exposure to light...
During the day:
Expose yourself to bright sunlight in the morning. The closer to the time you get up, the better. Have your coffee outside, for example, or eat breakfast by a sunny window. The light on your face will help you wake up
Spend more time outside during daylight. Take your work breaks outside in sunlight, exercise outside, or walk your dog during the day instead of at night.
Let as much natural light into your home or workspace as possible. Keep curtains and blinds open during the day, and try to move your desk closer to the window.
If necessary, use a light therapy box. This simulates sunshine and can be especially useful during short winter days.
Avoid bright screens within 1-2 hours of your bedtime. The blue light emitted by your phone, tablet, computer, or TV is especially disruptive. You can minimize the impact by using devices with smaller screens, turning the brightness down, or using light-altering software such as flux- most phones, or tablets, have a ’night’ mode setting.
When it’s time to sleep, make sure the room is dark. Use heavy curtains or shades to block light from windows, or try a sleep mask. Also consider covering up electronics that emit light.
Keep the lights down if you get up during the night. If you need some light to move around safely, try installing a dim nightlight in the hall or bathroom or using a small flashlight. This will make it easier for you to fall back to sleep.
Tip 3: Train during the day
People who exercise regularly sleep better at night and feel less sleepy during the day. Regular exercise also improves the symptoms of insomnia and sleep apnea and increases the amount of time you spend in the deep, restorative stages of sleep.
The more vigorously you resistance train, the more powerful the sleep benefits. But even light exercise—such as walking for just 10 minutes a day—improves sleep quality. It can take several months of regular activity before you experience the full sleep-promoting effects. So be patient and focus on building training habits that stick- like consistency!
Try to finish moderate to vigorous workouts at least three hours before bedtime. If you’re still experiencing sleep difficulties, move your workouts even earlier. Relaxing, low-impact exercises such as yoga or gentle stretching in the evening can help promote sleep.
Tip 4: Be smart about what you eat and drink
Your daytime eating habits play a role in how well you sleep, especially in the hours before bedtime.
Limit caffeine and nicotine: You might be surprised to know that caffeine can cause sleep problems up to 6 to 8 hours after drinking it. Similarly, smoking is another stimulant that can disrupt your sleep, especially if you smoke close to bedtime.
Avoid alcohol before bed. While a nightcap may help you relax, it interferes with your sleep cycle.
Tip 5: Wind down and clear your head
Do you often find yourself unable to get to sleep or regularly waking up night after night? Residual stress, worry, and anger from your day can make it very difficult to sleep well. Taking steps to manage your overall stress levels and learning how to curb persisting thoughts can make it easier to unwind at night. You can also try developing a relaxing bedtime routine to help you prepare your mind for sleep, such as practicing a relaxation technique, taking a warm bath, or dimming the lights and listening to soft music or an audiobook.
Problems clearing your head at night can also stem from your daytime habits. The more overstimulated your brain becomes during the day, the harder it can be to slow down and unwind at night. Maybe, like many of us, you’re constantly interrupting tasks during the day to check your phone, email, or social media. Then when it comes to getting to sleep at night, your brain is so accustomed to seeking fresh stimulation, it becomes difficult to unwind. Help yourself by setting aside specific times during the day for checking your phone and social media and, as much as possible, try to focus on one task at a time. You’ll be better able to calm your mind at bedtime.
Tip 6: Improve your sleep environment
A peaceful bedtime routine sends a powerful signal to your brain that it’s time to wind down and let go of the day’s stresses. Sometimes even small changes to your environment can make a big difference to your quality of sleep.
Keep your room dark, cool, and quiet Keep noise low. If you can’t avoid or eliminate noise from neighbors, traffic, or other people in your household, try masking it with a fan or sound machine. Earplugs may also help.
Make sure your bed is comfortable. Your bed covers should leave you enough room to stretch and turn comfortably without becoming tangled. If you often wake up with a sore back or an aching neck, you may need to experiment with different levels of mattress firmness, foam toppers, and pillows that provide more or less support.
Reserve your bed for sleeping and….🍆 By not working, watching TV, or using your phone, tablet, or computer in bed, your brain will associate the bedroom with just sleep and…🍆 which makes it easier to wind down at night.
To FINISH, sleep is pretty damn important for overall health, so ensure you're getting a sufficient amount, along with adequate quality- is imperative. Don't go looking for the latest and greatest nutrition/training strategies, or progression models, if you're neglecting the most foundational thing like proper sleep.