Wellbeing

The restorative power of sleep

Key ways to improve the quality of slumber: from weight management to the perfect sleep environment.

Written by David Cameron-Smith
An attractive young couple sleeping peacefully in bed

Sleep is an amazing and complex feature of human life. The power of sleep is apparent to anyone who has survived even one or two nights in a row where sleep time is reduced.

This short-term sleep deprivation can have devastating effects on mood and mental performance. For athletes this can put them at a disadvantage, impairing decision-making and aerobic performance. In the business world, jet lag or just a bad night’s sleep can cloud thoughts and diminish the ability to sustain concentration for any length of time.

For two-thirds of the population a rough few nights are generally followed by some much needed restorative sleep. Yet almost one in three people experience varying degrees of chronic insomnia.

The definition of insomnia varies, but generally it includes one of the following: difficulty getting to sleep, difficulty staying asleep, waking up too early, and having sleep that leaves sufferers tired and unable to function properly the next day. The risks of chronic insomnia climb with stress, shift work, weight gain and ageing.

The best example of stress is during examination periods or with tight work deadlines. A combination of long hours of concentration, often accompanied by an increased intake of stimulants like caffeine and cigarettes, all compound the risks.

The sleeping troubles of shift workers can persist even after years of working. Most shift workers have an impaired quality of sleep, even if they are able to get enough time in bed. Shift workers, potentially as a consequence of the loss of sleep, are also at increased risk of weight gain. It is an expanding waistline that poses the greatest threat to a decent night sleep.

Weight and sleep

Weight gain increases the amount of fat on the chest, throat and even the tongue. Fat accumulates at the base of the tongue, which can block airflow during sleep cycles. Blocked airflow leads to cycles of snoring and asphyxiation (lack of oxygen) that wakes the person up.

This cycle of temporary asphyxiation is followed by the person waking up very quickly and then falling back to sleep. This is known as sleep apnoea and requires medical intervention. It also leads to the person being very tired and can have a devastating impact on daytime functioning if left untreated.

Paradoxically, poor sleep can compound weight gain. Being constantly tired increases stress eating, decreases the drive to be physically active, raises stress hormones and contributes to depression.

Creating a good sleeping environment

Sleep begins with a dedicated group of nerve cells deep within a part of the brain known as the suprachiasmatic nucleus. Starting with these few nerve cells, signals are sent out through nerves and then hormones that control the 24-hour human cycle. These nerve cells process information from surrounding visual nerves and other parts of the brain including nervous activity that arises from stress and mood.

Good sleep cues start with ensuring the suprachiasmatic nucleus receives the right information. The right information is darkness. Turning off the lights or falling asleep away from flickering screen helps deliver the right information into the brain. Computers, handheld devices and TVs don’t belong in the bedroom.

It follows that lowering stress levels also helps the suprachiasmatic nucleus. Improved stress management might not be achieved overnight, but it is rare that problems are ever successfully solved over a sleepless night.

Food, drink and bedtime routines

There is very little scientific data on foods that help with sleep. However eating several hours before bedtime and avoiding evening caffeine and alcohol can help. Herbal teas and warm milk may help, but their value is as much to do with good sleep routines and going to bed hydrated. Sleep, after all, is all about routine. Develop a bedtime routine that has you going to bed when you are tired, has you snug in the dark and thinking calming thoughts.

Written by David Cameron-Smith

Professor David Cameron-Smith is a health expert and the current Chair in Nutrition at the Liggins Institute, University of Auckland.

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