The Power of Sleep

Everywhere you look, there is a lot more focus on sleep than there has been over the past decade. Previously people would wear the badge of ‘don’t mind me, I’m just operating on 3 hours sleep’ with pride, but the narrative has now changed. It is now widely accepted that between 7 and 9 hours of sleep is what most adults need. But where has this research come from, what is the benefit of getting sleep and (most importantly) what can a lack of sleep look like in our day to day lives?

Sleep Stages (https://www.sleepfoundation.org/stages-of-sleep)

Winding back to the early 2000s, it was commonly accepted that adults only needed 6 hours of ‘core’ sleep per night, and anything extra doesn’t actually benefit us in any way (Ferrara & De Gennaro, 2001). This study does actually look further into the impact of insufficient sleep, but it is interesting to highlight how little sleep ‘experts’ believed we needed only 23 years ago! Around a similar time, scientists were beginning to study and understand what actually happens to us when we sleep. More analysis was being conducted into the brain activity during sleep, and sleep stages were being established. These served (and continue to serve) as a model for depicting how activity changes across a typical sleep cycle, through deep sleep up to REM.

So, what is the latest research around optimum sleep levels? The current recommendation for healthy adults is a minimum of 7 hours, up to around 9 hours (Cloyd, 2024; Scott et al., 2024). The upper limit is reflective of some evidence of increased cardiovascular disease in adults who sleep more than the 9 hours, however sometimes that may be required! Before coming back from Cyprus, in a night flying sleep routine, I was struggling to get to sleep. I needed to be up at 7am to get over to check-in, so got myself into bed at 11pm. I attempted to go straight to sleep, however the previous five nights I had been finishing work at 3/4am, so quite clearly at 11pm I wasn’t at all sleepy. I tried music, some meditation, nothing was making me tired. Instead, I opted to put a TV series on I was watching, and before I knew it, it was 3am. The yawning had started, but all I could think about was that 7am alarm.

I started worrying that I’d end up missing my alarm and subsequently the flight home, which in itself stopped me sleeping! It was almost 4am by the time I drifted off. Fortunately, I made my alarm and got to the flight without any hiccups, but didn’t manage to get any sleep either on the flight or the drive back home afterwards. That night I slept an undisturbed 11 hours. There is conflicting research around us developing a sleep ‘bank’, however in the short term, I clearly needed to ‘catch up’ on the sleep missed. Funnily enough, the following night I also seemed to need over 9 hours sleep, but my 8-hour regular pattern was back by the third night.

If we cycle back to the introduction, where some people can operate on much less than the recommended sleep duration (3 hours may have been an exaggeration, but you get the point). Some people may be able to function on significantly less sleep, but how does not making your 7 hours actually affect your daily life? Firstly, if we are living active, healthy lifestyles, our bodies are being drained throughout the day. Sleep is primarily an opportunity for the body to rest. It allows our muscles to recover, toxins to be released and our brain to process its day. A lack of sleep can bring about a lack of energy and tiredness, even from just one night of 3 hours!

Although our body is at rest, sleep is a very active time for our brains. Therefore, neglecting to provide this space for our brains can have an impact upon our cognition. Depression is closely linked with insomnia (Baglioni et al., 2011) and those who miss out on sleep are twice as likely to develop depression. Although insomnia and depression are larger, more chronic condition, there are also more acute indications. Whether it’s in ourselves or those around us, moodiness and agitation is quite often associated with poor sleep. Did someone get out of the wrong side of the bed this morning…

Deep sleep serves an important purpose in our memories. It is where learning occurs; things we have stored from the day are encoded into our long-term memory during this stage. Studies have looked into students who reduce sleep to study more, which have found this to have a negative impact; they haven’t afforded their brains sufficient time to encode the information into their memories (Okano et al., 2019). Furthermore, this stage of sleep enables our brains to clear itself of toxins that have built up across the day. An accumulation of these toxins has been seen to contribute towards cognitive impairment issues, such as dementia and Alzheimer’s (Grigg-Damberger & Foldvary-Schaefer, 2022).

Too much sleep (hypersomnia) can also lead to similar conditions experienced with too little. According to the Sleep Foundation regularly oversleeping can decrease immune function and lead to chronic diseases. The same site offers some suggestions for combatting oversleeping, such as creating good routines and sleep environment, to provide the best conditions for sleep, as well as avoid napping where possible and remaining active.

Ultimately, sleep is a crucial function affecting human performance, and quite rightly it is gaining more focus and attention. The better we sleep, the better we perform, so it’s worth having a review of our own sleeping patterns from time to time, and look for ways we can improve.