SURPRISE SCIENCE OF SLEEP

Your bedroom environment can dictate how well you rest each evening – and getting it wrong could impact your long-term health, writes Kim Jones

GO DARK

Longer summer evenings mean more of us struggle to fall asleep. But a dark bedroom not only helps you get to sleep, it’s also good for your general health.

A study by Northwestern University in the US found even moderate ambient lighting, such as a hall light, keeps your autonomic nervous system activated and increases your heart rate. It means your body can’t rest properly and glucose regulation is impaired, which could put you more at risk of heart disease, diabetes and high blood pressure.

SILENCE PLEASE

Keeping the window open on a balmy night to cool down could leave you exposed to traffic. It not only disturbs your sleep, it could also harm your heart.

Research from Rutgers Robert Wood Johnson Medical School in the US suggests heart attack rates in places where there’s a lot of traffic noise could be 72 per cent higher than in quieter areas.

It claims high-noise exposure was to blame for one in 20 heart attacks in New Jersey, where the study ran. The team believes long-term exposure that disrupts sleep can cause stress and trigger anxiety and depression, which all affect your heart. Protect yourself with earplugs, as plenty of research has shown they can help patients sleep in hospitals.

But, warns Christina Graham, nurse practitioner and coach at Noom (noom. com), a digital health programme focused on long-term behaviour change, “regular use of earplugs can also push ear wax deeper into the ear and potentially lead to impaction”.

“Try using a white-noise machine or fan instead. A low hum can help us sleep through abrupt changes in sounds and research shows white noise may help us to get more time in deep and REM sleep, the stage where we dream,” she added.

GADGETS? IT COULD BE COMPLICATED

To promote a peaceful and low-light sleep environment we’re usually advised to keep electronic devices out of the bedroom.

“Blue light emitted from screens can delay the release of sleep hormone melatonin,” said Christina.

However, research published in the Journal of Sleep Research found that people who watched a movie or YouTube videos in bed felt no adverse impact.

The key? Keep it a short, focused session.

And don’t multitask by swapping between one screen and checking emails on another.

MOVE OUT

No, we don’t mean leave home, just your bedroom. Well, on hot nights, anyway. A research paper published by Loughborough University suggests around a fifth of homes overheat in warm weather (the ideal ambient temperature for sleep ranges between 15 to 19C) but threequarters have rooms downstairs that could provide a cooler retreat.

“A cool sleeping environment helps facilitate the drop in body temperature that’s necessary for us to move into the deeper stages of restorative sleep,” Christina said.

It’s particularly important for those who struggle to get the shut eye they need.

According to a team from the University of South Australia, those who suffer from insomnia typically have a hotter room when they first go to bed.

A difference of just half to one degree could make a difference.

AIM FOR EIGHT TO HYDRATE

We all know we need to remain hydrated to function well throughout the day, but many people will cut back on drinking in the hour or so before bed to avoid waking up to pee.

A study of data from 20,000 adults in the US and China has found that your bedtime routine can impact your hydration levels in a far less obvious way.

The team discovered that people who sleep for only around six hours a night were as much as 58 per cent more likely to be dehydrated than peers who make sure they get the recommended eight hours’ kip.

While not yet fully explained, the initial theory is that if you rise early you can’t fully benefit from a hydration-related hormone called vasopressin, which our bodies release day and night to control our fluid levels, but produces far more quickly in the early hours.