How to sleep well

How many hours of sleep do we need a night? Take a guess. Let’s firstly look at some other members of the animal kingdom. Do you know how many hours of sleep a bat needs? Or an elephant?

When zoologists study animals they tend to find a pattern of how much they sleep. So through studies scientists have identified that bats sleep around 19 hours a day, while elephants sleep just 5. Every type of animal has an optimal amount of time that they need to sleep and humans are no different.

Some of us fool ourselves into thinking that we can operate well on 5-6 hours, but science tells us it will have a detrimental effect on our health, our memory, our ability to communicate and our concentration levels. The research is very definitive here. We need to get between 7-9 hours as the optimal amount. 

There is one particular study here which is important to look at. A researcher called David Dinges at the university of Pennsylvania carried out a wide scale study to test how long a human can go without sleep before their performance is impaired. Dinges set up a series of fairly simple concentration tests to measure this, where response and reaction times are measured. He set up different control groups, each of which were allowed a different amount of sleep throughout the experiment. 

The most worrying result was that the control group who were only allowed six hours of sleep a night, performed considerably worse than the group who were allowed 8 hours. Ten days of six-hours sleep a night was all it took to become as impaired in performance as going without sleep for 24 hours straight. 

We often shave off time from our sleep when we’re busy but this should be the last thing to go. It’s counterproductive as our output, and our quality of work majorly decreases.

Our sleep cycles 

We need to look into the two different cycles of our sleep so we can create a deeper understanding of the benefits of sleep.

One is REM (rapid eye movement), otherwise known as our dream sleep.

The other is NREM (non-REM), otherwise known as deep sleep. We should have 5-6 cycles of sleep a night and you will alternate between REM and NREM throughout the night, with each sleep cycle lasting around 90-minutes. 

Both of these cycles of sleep have different but equally as important functions.

You will generally get a higher proportion of deep sleep phases towards the beginning of your sleep cycle and more REM sleep towards the end, which would typically be the morning. So if you go to bed later than usual one night, you will miss out on deep sleep and if you wake up earlier than usual, you will miss out on REM sleep. 

Let’s look at the benefits of both of these cycles.

REM Sleep

REM sleep helps us to regulate emotional activity – a key emotional intelligence skill. I want you to think back to a time when you were really sleep deprived. Did you find your patience with other people had decreased? Or that you were quick to snap at others? This is all down to our ability or inability when we’re sleep deprived to regulate our emotions. It’s a core emotional intelligence skill and one which is compromised when we don’t have enough REM sleep. 

This phase of sleep also helps us to accurately read the emotions of others. 

Sleep scientists believe that the reason we dream is to strip away any emotional trauma from experiences we have during our waking lives, which helps us process that trauma and move on from it. 

Research has shown that when we dream about the emotional themes and sentiments of the waking traumas we experience, even if it’s not in a literal way, we are much more likely to gain resolution and overcome the trauma. 

There is evidence to suggest that the REM sleep of PTSD sufferers is disrupted, limiting their ability to strip away the emotional pain of their trauma and leading to reoccurring nightmares.  

REM sleep also helps us with creative problem-solving and idea generation, so if we’re trying to be creative at work, we want to make sure we’re getting a good night’s sleep.

NREM Sleep

Let’s now look at NREM cycles, or what we also call the deep sleep phases. 

This phase of sleep is responsible for memory consolidation. 

Have you ever wondered why at a networking event you forget someone’s name moments after them telling you? Well our brain has a temporary storage center for new information called the hippocampus. When we receive information it goes to the hippocampus first and we initially recall it from there. 

The hippocampus however has a limited amount of storage space, so during the deep sleep phase of sleep, the brain transfers these memories into an area of our brain called the Neocortex, which transfers them into memories we can retain. 

This is a much bigger space where we can store lots more information and turn it into long-term memories. 

If we don’t get enough deep sleep, the brain cannot carry out this process of ‘banking the memories’ sufficiently, which means our hippocampus stays full. So when someone says, hi nice to meet you I’m Rachel, we don’t have space in our temporary brain storage to put that new information in so we immediately forget it. We also then over time forget a lot of the new things we’ve learnt as the process of banking the memories isn’t happening as frequently as it should. So deep sleep is incredibly important. We tend to get most of our deep sleep towards the beginning of our sleep cycle, which means if we go to bed later than usual, then we’re going to miss out on some essential deep sleep phases. 

Deep sleep is also responsible for motor skills, immune system recovery and activating our parasympathetic nervous system; the component of our nervous system that is responsible for rest and recovery. 

Lastly we know this phase of sleep is crucial for our cardiovascular health. In fact, we came across an interesting but scary study about sleep’s impact on cardiovascular health – many researchers have spent years gathering data from hospitals and have found that during the daylight saving adjustment in March (where the clocks go forward), there is always a spike in heart attacks the following day. They also found that in October when the clocks go back, the amount of heart attacks drops the following day. 

The difference of losing an hour of sleep can affect our cardiovascular health quite dramatically.