Why We Need Sleep
People tend to view sleep as a period of time when we crash out after a hard day’s work, a bit of downtime to recharge the batteries so we can get back to the grind. This couldn’t be further from the truth. Sleep is much more than a convenient stop-gap.
Sleep is an active period where our body performs a lot of important processing, restoration and rebuilding. Our bodies are naturally programmed for set periods of sleep.
These are the estimated optimal sleep durations:
- A one-year-old will need between 11 and 14 hours of sleep.
- A toddler between 9 and 11 hours of sleep.
- An adolescent between 8 and 10 hours of sleep.
- An adult between 7 and 9 hours sleep.
So, don’t be so hard on your teenager if he/she just wants to sleep in all the time!!! It’s not their fault!
You cannot binge sleep in order to catch up for the hours lost. This means that 14hr lie in on Sunday morning will do nothing to address a long-term sleep deprivation problem.
1 – Memory
When we sleep we consolidate information, skills and memories that we have picked up during the day – data is moved from short-term to long-term memory. Think of it like you are hitting the ‘SAVE’ button when you go to bed. This new information can only be used effectively if it has been stored properly first i.e. with sufficient sleep. A large part of this process occurs during the REM stage of sleep (Rapid Eye Movement). As such, if you do not achieve a quality night’s sleep then this consolidation process is negatively impacted.
Researchers have proved that we perform better on memory tasks when we have had sufficient sleep. Productivity also improves after adequate sleep – I’m sure we can all relate to being at work after a late night (possibly with the addition of alcohol) and not being able to perform basic tasks or be as reactive to situations the next day. It’s a no-brainer!
2 – Exercise and Performance
In terms of athletic performance, sleep is the time during which our bodies are rebuilding. We damage our muscle tissue whilst we are training, and it is during sleep when these structures are rebuilt. And if we are progressively overloading, then they will be rebuilt stronger.
When you read about the importance of recovery after training, we are not just referring to rest days; we are also referring to sleep. Gains are not made in the gym, they are initiated in the gym and then consolidated by the right nutrition and adequate sleep and recovery. So, if your purpose is to get stronger, to build muscle, to get fitter or to perform better (surely that’s everyone, right??), then you are wasting all your hard efforts if you are neglecting sleep. It’s like taking 2 steps forward and then 1 big step backwards.
In a study on basketball players, longer sleep was shown to significantly improve speed, accuracy, reaction times and mental well being. I’m sure the findings would be similar amongst any athletes.
In a separate study of 2800 women, the results showed that poor sleep was directly linked to slower walking, lower grip strength and difficulty performing independent tasks (whatever that category might be!). Either way, these are all abilities that will serve us well in life and in old age.
3 – Muscle Building
During sleep, growth hormone is released and muscle building takes place. Muscle building is a function of protein synthesis which is why you’ll often read about physique athletes consuming carbs and protein immediately before bed, in order to create the ideal environment for anabolism. Similarly, we know that the more quality sleep that men can accumulate the greater their testosterone production will be. This will further aid strength and muscle gains but also counteract the damaging effects of elevated cortisol levels which occur with prolonged stress and insufficient sleep. So if you want to build muscle then do the work, but make sure you eat and sleep well too. Hopefully, you are now starting to see a pattern here? Exercise… Nutrition… They are nothing without recovery and sleep.
4 – Depression, Immune Function and Inflammation
Inadequate levels of sleep are often linked to depression. It is estimated that 90% of people with depression complain about deteriorated sleep quality. Conversely, those with sleep disorders (such as sleep apnea) report significantly higher rates of depression than those without. Food for thought! Perhaps this is not enough to conclude that insufficient sleep causes depression, but it is another link to how our body’s ability to function is altered.
Have you ever found yourself picking up colds and annoying illnesses more than you should? This is often linked to stress, and insufficient sleep is an additional layer of stress. If you are training hard, working hard, dieting and THEN not sleeping properly then you are throwing stress at your body from all angles. Eventually, something has to give. These are all types of stress.
Persistent colds are an internal alarm telling you that something needs to change or, often more notably, that you have a weakened immune system. Research has indicated that getting 8 hours of sleep per night can improve immune function and help fight the common cold (you could also add a bit more garlic to your diet if you like!)
Inflammation makes its presence known in a number of ways. It is your body’s response to a stimulus such as a foreign body, an infection, injury or condition. Persistent inflammation can lead to painful joints, irritable bowels or arthritis among other things. It can also lead to chronic disease because it disrupts our body’s ability to turn off our ‘response’ switch – if this happens, then your body thinks that it is always under attack. Lack of sleep is known to activate markers of inflammation that can lead to cell damage.
5 – Circadian Rhythm
You may have heard of the “Circadian Rhythm” and wondered what the hell it was. Essentially, it is our internal body clock that is working 24/7. You may have noticed feeling drowsy at certain times of day (e.g. after lunch) or feeling alert at other intervals during the day – these are both due to the Circadian Rhythm. This internal body clock is always running in the background, and cycles between states of drowsiness and alertness – which is why it is also known as the sleep/wake cycle.
Some people may find they have peaks and troughs at different parts of the day, however, the important point to note is that your Circadian Rhythm works best with consistency in your sleep patterns (see this post for more on the importance of consistency). It is controlled by the hypothalamus in the brain. It also responds to light patterns, such that during daylight you feel more awake and at night time you feel sleepy (this is because the hypothalamus sends a signal to release melatonin which makes us drowsy). This is why our Circadian Rhythm tends to work best alongside night and day – I performed shift work for just over 9 years and I can attest to the fact that the body does not like sleeping as well during the day.
The Bottom Line
The bottom line is this.
- Sleep is essential for processing information, learning new skills and creating long-term memories. It also enhances our ability to perform tasks.
- Sleep improves athletic performance – this includes speed, accuracy, reaction times and mental well being – and is essential to build muscle and strength.
- Sleep can combat cortisol – the ‘stress’ hormone. If you have stress in your life then sleep is a natural antidote to its adverse effects on your body.
- Sleep can improve our resilience against depression, inflammation and a weak immune system
I have thrown quite a lot of information at you in this article but I hope to have highlighted the importance of sleep and why you should make it a priority. If there is one take-home message then it is this – please take your sleep seriously, as seriously as you do your exercise, nutrition and general well-being.
In the next article, I want to highlight ways that you can maximise your sleep in order to optimise your health.
Author - Craig Peterson - Personal Trainer & Mentor
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