Deep Sleep: What It Is & Why It’s Important

Deep sleep, also known as slow wave sleep, is a stage of NREM (non-rapid eye movement) sleep which usually occurs during the third stage of your sleep cycle. During this sleep stage your body is at its most relaxed and won’t wake easily, even from loud noises. If you do wake during this sleep, you may feel groggy or tired.

During deep sleep you experience certain physiological changes including:

• Slower heart rate and breathing
• Relaxed muscles
• Brain waves at the slowest they will be during your entire sleep

It occurs for longer periods during the first half of your sleep and the longest period of deep sleep will happen quite soon after you fall asleep. This stage can last from 45 to 90 minutes but will get shorter during each sleep cycle until eventually it stops.

As well as physiological benefits, it is also the point in your sleep cycle where you process information. A lack of it means your brain can’t convert information you’ve received throughout the day into memory. That’s why cramming for an exam the night before rarely works!

Deeper sleep is, therefore, extremely important for both your physical and mental health and not getting enough has been linked to health problems later in life. A recent study by the Washington University School of Medicine in St. Louis found that adults who do not get enough deep sleep have higher levels of a brain protein called tau which is linked to Alzheimer’s disease.

Furthermore, the NHS warns that ‘regular poor sleep puts you at risk of serious medical conditions, including obesity, heart disease and diabetes – and it shortens your life expectancy’.

There is no singular way to increase the amount you get. However, improving the quality of your sleep overall and the amount of sleep you get can help.

Ways to improve your sleep:

• Set yourself a sleep schedule and stick to it! Waking and sleeping at the same time each day will reset your body clock.
• Have a bedtime routine – take a bath, read a book or drink some calming herbal tea. Stay away from heavy foods or caffeine as this can disrupt your sleep.
• Stop using electronic screens with bright lights such as phones, TVs or laptops in bed. Blue light stops the production of melatonin (the sleep hormone) and tricks your body into thinking it’s the day time.
• Exercise for around 20-30 minutes each day. This doesn’t have to be strenuous, even walking will do the trick! Try not to work out too close to bedtime or it can have the opposite effect.
• If you can’t sleep, get up and do something relaxing rather than tossing and turning. Gentle yoga stretches, reading or one of these other relaxation techniques can help.