Why is Sleep Important?

*We all know what it feels like after a bad night’s sleep - we’re tired, irritable, have poor attention and memory, and make worse decisions. Sleep plays a critical role in our physical health and psychological well-being, affecting our circulatory, respiratory, metabolism, and immune system. However, it can often feel like consistently getting a good night's rest is in itself a dream.*

### Sleep's impact

Poor sleep is a precursor for several health problems, including heart disease, stroke, obesity, diabetes, and cancer. Sleep helps the body enter a recovery mode - repairing cells critical for biological functioning that have been naturally damaged during the day [1]. This is supported by processes accompanying muscle repair, regulation of hormonal production, protein synthesis, and tissue growth predominately occurring when we are asleep. Healthy sleep is essential to every process in the body, but how does it work?

### Sleep Science

We all have an internal body clock that follows an approximately 24-hour cycle and influences our sleep-wake cycles - determining when we feel awake and when we feel tired. Humans have a built-in schedule for being active during the day and to sleep throughout the night. This sleep regulation is determined by two interacting components that influence when we feel tired, alert, fall asleep, and wake up: a build-up of homeostatic drive for sleep and our circadian rhythm.

After we fall asleep, our bodies cyclically follow distinct stages of sleep. These stages can be divided into two categories: rapid eye movement (REM) sleep, and non-rapid eye movement (NREM) sleep.

- #### Stage 1 NREM sleep

This is when you first begin to drift off. Our body is yet to completely relax, but our brain activity starts to slow, along with our heartbeat and breathing. Our muscles also sometimes twitch.

- #### Stage 2 NREM sleep

We enter a slightly deeper stage of sleep. Our body temperature drops, our muscles relax, and our heart rate and breathing slow down.

- #### Stage 3 NREM sleep

This is our stage of deepest sleep. Being woken up when we are in this state can make us feel confused and very groggy. Our body is fully relaxed. It is believed that this stage is responsible for the rest and repair needed for the next day.

- #### REM sleep

Our brain becomes nearly as active as when we are awake, despite our body being paralysed everywhere but our eyes (hence being characterised as rapid-eye movement) and the muscles responsible for breathing. It is in this stage we typically dream, although we also dream during NREM sleep. Interestingly, it is suggested that REM sleep is responsible for processing and storing emotional memories, and is critical for emotion regulation! [2]

### How Much Sleep Do We Need?

Sleep is vital for our physical and mental functioning, but knowing exactly how much sleep we need can be a tricky question. Each individual has different sleep needs, but a good rule of thumb is to aim for 7-9 hours a night. Sleeping too little, or too much, has been associated with maternal and foetal outcomes [3], therefore it is important to take sleep seriously. Difficulties with sleep are common during pregnancy, and there are lots of things we can do to improve our sleep in order to improve outcomes for ourselves and our babies.

### Getting Better Sleep

Once your baby arrives it is likely that getting a sleep-filled night may not be so common, so try to make the most of sleep while you can! Mastering sleep hygiene can take some time, so be patient, and consistent, and make gradual changes - you won’t become a sleep master overnight!

- Sleep in a cool, dark, quiet room. Temperature, light, and noise all impact our sleep.

- Have a regular bedtime. We understand this can be a real challenge in keeping up with modern-day life, but it is important to make consistent bed and wake-up times a habit (at least as best we can!).

- The hour before you sleep should be screen-free. Pick up that book you’ve been wanting to get stuck into!

- Get regular exercise, but make sure it’s earlier in the day!

- Stay hydrated throughout the day, but limit your drinking before bed.