Doctors now recommend a minimum of 7-9 ‘quality’ hours of sleep per night over the previously recommended 6-hours, and if we fall short, we may be putting ourselves at an increased risk of weight gain, mental health issues, degenerative brain diseases and cardiovascular risks, such as heart attacks and stroke - scary news considering one in every two people in the western world are sleep deprived!
But don’t just take my word for it…
Experts studying the performance of resident junior doctors found that doctors working a common 30-hour shift were 460% more likely to make diagnostic errors on intensive care units than their counterparts on 16-hour shifts, and surgeons who had only 6-hours sleep or less the night before surgery had a 160% increased risk of major surgical error! Not only that, ironically, resident doctors leaving a 30-hour shift were 168% more at risk in being involved in a car accident on the way home than if they were well rested!
And these sleep studies don’t just relate to cognitive function; a recent study has shown that when normal every-day people were subjected to only 4-hours sleep on a single night, apart from cognitive performance impairment, they also showed a 70% reduction in cancer killing cells - and once a year, when spring daylight savings time occurs (we lose an hours sleep), there is a subsequent 24% increase in cases of heart attack! Almost impossible to believe, except when we gain an hour of sleep in the autumn, there is a converse 21% decrease in cases of heart attack!
This is just a fraction of the new data revealing the underlying importance of sleep and it is clear quality sleep is a highly undervalued aspect of healthy life, which can cause us serious harm, psychologically and physiologically, if we do not fulfil our needs.
The Sleep Cycle
So, we now understand the negative health implications associated with lack of sleep but what separates an average night’s sleep from quality sleep?
Our sleep cycle is a 90-120-minute revolving process of 4 different sleep stages, all responsible for different functions.
Stages 1 and 2 are also known as ‘Light Sleep’ and are the preparatory stages of sleep before the more important stages of deeper sleep. At these stages our bodies begin to ‘doze off’ by lowering our core temperature and decreasing muscle tone. It’s also very easy to wake during stage 1 and 2.
Stage 3 is categorised as Deep Sleep or Deep NREM sleep and is the most restorative stage of sleep, responsible for regeneration of cells and cognitive functions such as learning. Waking from this stage is rare, however this stage is also where sleep walking and night terrors occur.
Stage 4 is categorised as REM Sleep, also known as ‘rapid eye movement’ and is the stage of sleep where dreams occur. Although it’s quite easy to wake from REM sleep, waking at this time can cause cognitive impairment and feelings of unrest and grogginess.
It is stage 3 & 4 which contribute to what is defined as ‘quality’ sleep and that which we must maximise for optimal health and performance, however in today’s world of stress, artificial light and simulants, ‘a good night’s sleep’ is becoming rarer and rarer.
Here are 5 common factors which impair our sleep, and how we can fix them…
5 factors which can impair sleep
1. Light
Light helps regulate our circadian rhythm (our biological clock) by affecting the secretion of the hormone, Melatonin, which signals your body that it’s time to sleep. Blue light, which is produced by the sun but also by the screens of TV sets, computers, and smartphones disrupts your production of melatonin and can delay the time it takes your body to reach deep sleep by 3-hours!
To reach essential deeper sleep and REM sleep sooner (where the benefits of sleep lay), turn all of your bedroom electronics off at the switch, try to turn your phone off 2-hours before sleep, read a book under dim light and use black out blinds to plunge your bedroom into darkness.
2. Caffeine
Although Caffeine is a safe and mostly beneficial stimulant, caffeine’s varying effects on adenosine receptors in the brain can cause unwanted effects when used at inappropriate times. For example, when caffeine blocks the A2A receptor, dopamine is increased, and we may experience a stimulant and mood-enhancing affect, however when caffeine blocks the A1 receptor, the receptor which promotes sleepiness, we may experience a feeling of wakefulness which is less than desirable when it’s time to hit the hay.
The main problem with caffeine lies with how our body becomes desensitised to caffeine. The more caffeine we consume the more our bodies become desensitised to caffeine’s desirable effects on the A2A receptors, however our bodies do not become desensitised to caffeine’s effects on our A1 receptor, which means people who need a lot of caffeine to feel the desired affects are also greatly reducing their bodies ability to reach deep sleep and sleeps regenerative benefits.
Cut the caffeine 6-hours before sleep and if you have a particularly high tolerance, you will find ‘cycling’ caffeine to be extremely beneficial in aiding sleep but also actually feeling the desired effects of caffeine.
3. Heat
Elevated core temperature has been associated with Insomnia and conversely sleeping in a cool room has been associated with a faster level of deeper sleep, therefore ditch the heated blanket and try to sleep in as little clothing as possible!
A quick hack to improve your quality of sleep – take a hot bath right before bed time! You may think this to be counter-productive considering heat can negatively affect our sleep, however when we get out of the bath our body instantly cools our core temperature by flushing blood through the vessels closest to our skin and ‘dumping’ heat. This is why we may have red faces and sweaty palms.
4. Inconsistent Sleep Schedule
Bad news for shift workers. It is now well documented that due to shift works influence on our bodies sleep patterns and circadian rhythms, shift workers pose themselves at a much greater risk of serious diseases, such as Alzheimer’s, Dementia, Cancer and a greater risk of premature death.
Most physiological processes within our bodies follow a 24-hour schedule, based on clues such as temperature and light (which is why artificial light negatively effects the quality of our sleep). This 24-hour schedule is your circadian rhythm, and by throwing it into disarray, an inconsistent sleeping schedule is likely to impair the quality of your sleep. Going to bed at approximately the same time every night can improve sleep quality as well as reduce the time it takes you to fall asleep.
To benefit your circadian rhythm and reinforce sleep signalling, try to install a ‘sleep routine’. This routine can be as simple as showering and brushing your teeth, or it can involve a set amount of time spent reading or meditating before you close your eyes.
5. Alcohol
In the past, a traditionally common ailment for sleep has been alcohol, however even though physiologically alcohol seems to benefit sleep (by acting on GABA receptors and depressing the central nervous system), the research shows otherwise…
Under occasional influence alcohol may help you fall asleep faster however alcohol negatively affects our ability to reach a higher quality of deep sleep, so although you may think alcohol is helping, it is actually inhibiting your bodies essential regenerative processes which take place during deep sleep.
Don’t use alcohol as a sleep aid — it might help you relax, but it will impair the quality of your sleep. You may find it beneficial to avoid alcohol after dinner.