Sleep is vital for your health and wellbeing and it’s important that you are getting enough good quality sleep. But how much sleep do we need?
How much sleep do we need?
The recommended amount of sleep for adults can vary based on a range of factors, including: Age, gender, lifestyle, and health issues.
Studies have suggested that the average adult needs between 7 and 9 hours sleep, but as everyone is slightly different, some people will need slightly less or slightly more than the recommended amount.
Fewer than 6 hour’s sleep is considered not enough for most adults under 65. For most adults, sleeping in excess of 10 hours per night may be be a symptom of an underlying health condition and should be investigated by your GP.
Normal sleep
Normal, healthy sleep consists of 2 stages:
Non-Rapid Eye Movement (NREM) Sleep
This is when our body does most of its growth and repairing. We experience the majority of our NREM sleep in the first third of the night. It is characterised by a lack of rapid eye movement, low levels of brain activity, and slow or no movement of the body.
Rapid Eye Movement (REM) Sleep
This is when we do most of our memory consolidation, processing our emotions, and dreaming. This stage of sleep is characterised by rapid and random movement of the eyes and vivid dreaming. During REM sleep, the brain becomes more active, and the body’s muscles become relaxed
Sleep cycle
As we sleep, we go through cycles of these different sleep stages – NREM sleep is typically experienced in the early part of the night and REM sleep is typically experienced later in the night.
As we sleep, the sleep cycle alternates between NREM and REM sleep. Each stage of sleep typically lasts for about 90-120 minutes and will usually go through 4 – 6 cycles each night.
However, the length of time we experience in each stage of sleep can vary depending on factors such as age, health, and sleep disorders.
Outcomes of poor sleep
Some outcomes of poor sleep can be obvious, but others may not be something you connect with fatigue and tiredness. You can use this list as examples of what to look out for as signs of poor sleep.
Daytime difficulties
The parts of our brains that help us plan, make decisions, evaluate danger, and manager our behaviour are impacted when we don’t get enough good quality sleep.
Poor memory & concentration
Sleep allows us to learn and remember things well because memories from the day move from our short-term to long-term memory while we are asleep. Without sleep this cannot happen, which is why pulling an all-nighter before an exam may do more harm than good.
Mood changes
Sleep deprivation affects our ability to store positive memories, but doesn’t have the same effect on negative or neutral memories. This can lead us over time to feeling like only bad things have happened because our brain cannot store the good things in the same way.
Mental health
Mental health and sleep deprivation are tightly linked and can create a cycle with one affecting the other.
Sleep deprivation can lead to symptoms of anxiety and depression, and individuals experiencing anxiety and depression are more likely to experience sleep deprivation.
Obesity
Good sleep helps us regulate our weight. When we sleep well, we produce more of the hormone that suppresses our appetite, but sleep deprivation increases the levels of the hormone that makes us feel hungry.
Lack of sleep will also cause increased levels of cortisol in our bodies, making us crave foods that are rich in carbohydrates when we are stressed. These foods break down quickly during digestion, giving us a glucose boost, which is then followed by an energy slump. This creates a cycle where we crave energy-dense food to give us another boost.
Compromised immune system
Our immune systems are complex and depend on a number of interconnected processes functioning consistently. Sleep deprivation can impair the release of hormones and the repair and maintenance of vital cells and proteins, resulting in increased chances of becoming unwell.
Studies have shown, for example, that lack of sleep can affect both the number and duration of colds that people catch.
