The heads up

A study from 2019 found that people who sleep less than six hours a night may have an increased risk of cardiovascular disease compared with those who sleep between seven and eight hours.

According to the research, less than six hours of slumber increases the risk of unhealthy plaque, or fatty deposits, building up in the arteries – a condition called atherosclerosis.

Previous studies have shown that lack of sleep also increases risk factors for other serious health issues, with links to high blood pressure, obesity and type 2 diabetes.

How many hours of sleep a person needs varies from person to person, but most healthy adults should aim for between 7-9 hours a night to function at their best.

Body temperature is involved in the sleep/wake cycle. At night, your core temperature dips naturally, helping to prepare your body and brain for sleep.

A warm bath or shower helps this process along, not by warming you up, as you would expect – but by cooling down your core temperature.

The warm water increases blood supply your hands and feet, taking body heat from deep inside and reducing your core temperature.

A review of the research found the optimal timing of bathing for cooling down your core body temperature to improve sleep quality is about 90 minutes before going to bed.

If you have the choice between a book and eBook, research shows it’s better to stick with the printed form for the sake of your sleep.

A 2014 study revealed that after reading an eBook versus a real book, participants took longer to fall asleep and had reduced levels of feeling sleepy in the evening. Their levels of melatonin (the sleep hormone) were also decreased, and their alertness the next morning was also reduced.

It’s well known that the blue light emitted by iPads, eReaders and phones can suppress melatonin (the sleepy hormone). Warm-toned ‘night mode’ settings on devices claim to negate any ill effects.

However, other studies (only done on animals so far) suggest it doesn’t only boil down to the big blue; yellow light, brightness, and how long you’re exposed to the light are also likely to be important factors to consider.

An American review of dozens of separate studies has confirmed that during times of hormonal change – such as puberty, pregnancy and menopause – women are at increased risk of poor sleep and sleep deprivation, as well as sleep disorders such as restless legs syndrome and insomnia.

Snoring or snorting mid-snooze is one potential sign of the condition known as sleep apnoea.

In sleep apnoea, your airway narrows or gets temporarily blocked by the surrounding muscles. This makes breathing difficult, waking you up momentarily mid-sleep.

These episodes might happen hundreds of times a night, but because you’re asleep while it’s all going on, you may not remember in the morning.

If you have a sleeping partner, they might tell you that you snore loudly, snort, have pauses in breathing or suddenly gasp for air.

However, not all snorers have sleep apnoea and not all people with sleep apnoea snore. It is important to be aware of the condition though, as it can increase your risk of heart disease and dementia.

Read our recent article: Is it tiredness or is it sleep apnoea?

While it may initially help you to feel drowsy and fall asleep, alcohol is a common cause of disrupted sleep, particularly in the second half of the night.

Research has shown that drinking before bed disturbs sleep cycles, makes you more prone to snoring and sleep apnoea, and it potentially leads to more bathroom trips during the night.

Even late afternoon ‘happy hour’ drinking – around six hours before bedtime – also disrupts sleep, even though alcohol is no longer in the brain at bedtime.

REM and non-REM sleep are the two main stages of sleep. REM sleep first occurs about 90 minutes after falling asleep.

In REM sleep, breathing becomes faster and irregular, heart rate and blood pressure rise to near waking levels, and brain activity also increases. Your eyes also move rapidly from side to side behind closed eyelids during REM sleep, hence its name.

Most of your dreaming occurs during REM sleep, but some can also occur in non-REM sleep. Interestingly, your arm and leg muscles become temporarily paralysed during REM sleep, which researchers believe helps us in staying asleep by preventing you from ‘acting out’ your dreams.