Sleep : What happens when we sleep?

Everybody needs sleep; without enough, it’s easier to become irritable and harder to function on our day-to-day tasks. Getting sufficient sleep can help to protect our physical and mental health, and enhance our quality of life.

What happens when we sleep?

To understand what happens to our body during sleep, we must appreciate the sleep cycle, which consists of two recurring phases: REM (rapid eye movement) and NREM (non-rapid eye movement). Both phases are important for different functions in our bodies.

NREM sleep accounts for about 75% of normal sleep time. It is during NREM that many of health benefits take place: tissue growth and repair occurs, energy is restored and hormones that are essential for growth and development are released.

REM sleep accounts for about 25% of a night sleep and occurs when dreaming takes place. During this phase, our body forms pathways to help us to learn and process information and consolidating emotions, memories and stress. When the REM and NREM cycle are constantly interrupted throughout the night, we miss out on vital body processes, which consequently will affect our health and well-being at short and/or long-term.

How it affects us…

Sleep deprivation can alter activity in some parts of the brain, and ultimately negatively affect on how well you think, react, work and interact with others. Some studies have established a link between sleep deficiency with increased risk of depression, suicide and risk-taking behaviour.

Sleep also plays a vital role in our physical health. Sleep can affect numerous hormones and metabolic processes in our body. One of its important functions is to heal and repair our heart and blood vessels.

Research has shown that a week of sleep deprivation can cause significant alterations in glucose tolerance. Impaired glucose tolerance can result in cardiovascular disease and diabetes. There is a growing body of evidence to suggest an association between obesity and sleep deprivation. Sleep helps maintain a healthy balance of the hormones that make you feel hungry (ghrelin) or full (leptin). When we don’t get enough, our level of ghrelin goes up and our level of leptin goes down. This makes us feel hungrier than when we are well rested.

Our immune system also relies on sleep to keep us healthy. This system defends our body against foreign or harmful substances. Ongoing deficiency can change the way in which our immune system responds, and increase the risk of fighting infections.


How much sleep do we need?

The amount requirement can vary from one person to another across the lifespan, but according to the National Sleep Foundation but general recommendations are:




As you can see, adequate sleep is vital to our health and wellbeing. There has never been a better time to get enough shut-eye to keep you are functioning at your best.