Why Do We Sleep?
Imagine how much extra time we’d have if up to one third of our lives wasn’t spent sleeping! Do we really need to sleep? If so, why?
Customer feedback regarding our June 2017 Newsletter Skin Health and Sleep was popular and we’ve been asked for more information, particularly on the importance of sleep. So…
Why Do We Sleep?
Our immediate thought might be that we sleep because we are tired … but how about switching that to: we get tired because our body needs us to sleep so it can do what it needs to do; that which it cannot readily do whilst we are awake! One reason we get tired is because our muscles produce lactic acid when working. It, and other produced substances, are like a poison and sleep removes this “poison” so our muscles are ready to take us through the next days’ activity.
Sleep is critical to our well being and it is a time when …
Our brain processes information
we all know how furry-headed we get when we’re tired. Our mind ceases to be sharp; we cannot readily recall information that normally would be at our fingertips. Studies show that we remember things significantly better when we follow the pattern of learning/studying then having a good nights sleep to solidify it. Our retention for that new information is so much better. If our children understand this, they can lighten their study load by becoming more efficient at learning and remembering. Memory is improved because during sleep there is “consolidation” whereby memories are processed and moved from short term memory (STM) to long term memory LTM. STM is great for temporarily remembering a telephone number long enough to dial, but LTM is needed so we recall info and events going back decades, including how to do things like drive, read and recognise people and things.
Our body restores its strength
suffice to say that our stamina and strength erodes with lack of sleep. And if you are ever awoken during your deep sleep cycle, your muscles will ache as that is the time when they’re going through rebuild and restoration. Best to sleep through undisturbed!
Our body rejuvenates
Yes! We look aged and haggard when we are not sleeping enough.
Our body tissue repairs damage
from the day’s activities: stiffness, aches and pains can be eased after a good night’s sleep.
and we have learned that when a baby sleeps, it is growing! So while an adult may not be growing as such, there is certainly a lot of maintenance and repairs underway.
How Long Do We Need to Sleep?
We need more sleep early in life (eg 14-17hrs per day for a new born baby), reducing to about half that as an adult over 65 years (7-8 hours). But each of us is an individual so sleep requirement time can definitely vary. If we’re self-aware, we’ll know what we need. We also need to understand that lost sleep cannot actually be made up (you can’t just repay the loan and all is well) so it’s in our health interest to work out and maintain a healthy routine that suits us as that individual.
How Do We Sleep?
Falling asleep is a progression of stages and cycles during which the body and brain activities are changing. It is defined by four stages with the first stage (now referred to as N1) being a light sleep, from which if awakened, one likely says one was not sleeping.
Stage two (N2) is similar and if awaken, one may not realise one has fallen asleep. About half of our period of sleeping is in generally Stage two. We have a calming brain pattern and our eyes don’t flicker (as in REM sleep – Rapid Eye Movement). Our breathing is slow and regular and our body temperature drops slightly*
*This is why, if we are having difficulty falling asleep, we are told to get up and let our body cool, even by sitting outside in the cool night air. Then climb back into a cosy bed.
During Stage Two (N2), we are no longer conscious of our physical surroundings but can easily be shaken awake.
Stages Three and Four (now jointly referred to as N3) are much deeper sleep periods, and it’s harder to awaken someone at this time. Breathing is a slow rhythm, blood pressure and body temperature drop a little further. These stages are referred to as “slow wave sleep” and is the deep, restorative sleep that our body requires for well-being.
Our body continually cycles, know as Basic Rest Activity Cycles (BRAC) which last approximately 90 minutes. You might recognise this example: one can be so tired at a late party, but if one perseveres and stays, we get a “second wind” … we’ve actually just moved into a new BRAC.
90 minutes after falling asleep, REM sleep sets in (Rapid Eye Movement). The slow brain wave of sleep increase to a similar speed or even faster than when awake. Most dream activity occurs during REM. Heart rate increases, blood pressure rises, breathing is faster and shallower, and of course, the eyes (still closed) flicker. Our body is paralysed to protect us acting out our dreams but we may twitch. REM periods last from just a few minutes to half an hour.
After REM, we revert to Non-Rem and the 90 minute (80-110 min actually) cycle repeats. This occurs about 6 times throughout the night. As the night progresses, REM time increases which means that our sleep progresses to being less deep, so morning arrives and we return to and awaken from the light Stage One or Two sleep. That is why we are encouraged to awaken naturally.
We also experience circadian rhythmns which align our body and sleep with night fall and sunrise. Cortisol and serotonin levels differentially rise and decrease … cortisol is the stress hormone that decreases at the end of the day so we’re able to sleep but it is at a high again on awakening so we can start a new day. Serotonin is the opposite.
Is All Sleep The Same? e.g. where do cat naps fit in?
A cat nap is not the same as sleep and cannot replace a good night’s sleep. But a cat nap of 20-30 minutes can improve alertness and performance. More often referred to now as a “power nap”, it’s a useful way to help revive our body particularly if our night time sleeping is not the best. But referring to the above, we can see that a 30 minute nap is definitely not going to take us into the Stage Three and Four (N3) deep “slow wave” sleep that our body must have.
And for those of us who remember something from High School, when we’re awake our brain emits the fast Beta waves of alert wakefulness.
It slows to Alpha waves when we’re in a state of relaxed wakefulness (as in meditation).
The even slower Theta waves occur during Stage One and Two (Non-Rem sleep, N1 and N2). And the deepest sleep (Stages Three and Four – N3) has our brain slowed to Delta waves.
When Should We Sleep?
Interestingly, our earlier stages of deeper sleep, progressively giving way to the lighter REM seem to be in synch with the clock, or should we say Mother nature’s clock…
… if we go to bed very late, as in the small hours of the morning, we sleep to the increased REM periods and miss out on the deep restorative sleep that occurs several hours prior, that the body needs. And this is why shift workers can suffer so. As humans, we have evolved to sleep at night and be awake during the day. Everything in our body and being has evolved that way. Doing anything different is very difficult – the body cannot adapt properly. All sorts of health issues have been linked to sleep patterns other than Mother Nature intended.
Some people like to go to bed earlier than others and this is generally something we cannot change in the long term. The idea is there is not much point going to bed when you are not tired. Same as there is not much point trying to stay up late when you’re tired. One tends as a youngster to need to go to bed early; whilst as a young adult, tiredness may not set in till very late evening. Then, as one ages, one tends to want to go to bed earlier but again this is an individual behaviour and our biological make-up will dictate. All we have to do is listen. What we are told though, is that once we have found the right bedtime and get up time, then we should keep to that rhythm whether its a work day or holiday.
But is any of this important? Well, yes … the above info shows why we need sleep, and lack of sleep brings all sorts of woes.
Sleep Deprivation
… is the condition of having insufficient sleep to the point of real compromised well being: fatigue, nodding off during the day, clumsiness. Weight gain can occur, mood changes, impaired memory and performance, difficulty concentrating and even pain. Whilst by definition it is the lack of sleep, the cause of the lack of sleep may be from sleep apnea, stress or medications. If left untreated, serious health concerns can rapidly escalate so it’s one’s very best interest to consider one’s sleeping habits and take action if they’re not within healthy parameters.
If one is not using “sleep” as Nature intended and getting the full benefits of it, it’s in our interest to look at the possible reason/s why.
And if poor sleep is your problem and you like the gentleness of homoeopathics, you might like to try our Stress and Tension (Insomnia) pillules.
Good Luck … and Good Night
We are not healthcare or medical professionals and the information contained here is not to be taken as medical advice. It is recommended that you consult you healthcare professional prior to taking any supplements and always read the label, use only as directed, and if symptoms persist, see your healthcare professional.