Sleep hygiene: how poor quality sleep affects your heart

When we think about protecting our heart, we often jump to diet, exercise, or stopping smoking.

But there’s a lesser-known pillar of heart health that’s just as important: sleep.

The American Heart Association (AHA) now includes sleep as one of its 8 essential activities for a healthy heart.

This puts quality sleep alongside a healthy diet, regular exercise, managing weight, lowering cholesterol, managing blood pressure, managing blood sugar and quitting tobacco as key to having a healthy heart.

How does poor quality sleep affect the heart?

First of all, what do we mean by quality sleep? While more research is needed, it’s thought that it’s not just how long we sleep that’s important.

There are 7 aspects to getting quality sleep:

duration: how many hours you sleep
continuity: how long you sleep in one go without interruptions
timing: what times of day and night you sleep
satisfaction: your own perception of how well you sleep
regularity: sleeping the same amount on weeknights as weekends
day-time functioning: how awake and alert you are in the day
architecture: whether you go through all the sleep cycle stages (see box below).

Most research into how sleep affects your heart is on sleep duration. And on the back of this, it is recommended to have 7 to 9 hours sleep a night.

This is because studies show that getting less than 7 hours a night on a regular basis is linked to higher risks of atrial fibrillation (AF), high blood pressure at night and cardiometabolic syndrome that raises the risk of heart disease, stroke and type 2 diabetes.

And sleeping more than 9 hours per night is linked to a higher risk of cardiometabolic syndrome, stiffer arteries, stroke or death from heart disease or stroke.

Sleep is also essential for reducing inflammation in the body. Regular poor sleep can send the body’s immune system into overdrive, which can cause damage to the inside of the arterial walls including the arteries in your heart. This can increase the risk of heart attack or stroke.

7 signs of poor sleep hygiene

Sleep is not just about what happens when your head hits the pillow, it’s shaped by everything you do in the hours, and even during the day, leading up to it.

Poor sleep hygiene are the daily habits and environment that can hinder you from getting the high-quality sleep you need for heart health.

Below are 7 behaviours that can stop you sleeping well and some good sleep hygiene tips to help avoid them:

1. Staying indoors all day

Time spent in the light during the day is one of the most overlooked factors when it comes to sleep.

If you spend all day indoors away from natural light, it can interfere with your body’s natural clock, making it difficult to fall asleep when it comes to bedtime.

Sleep hygiene tip:

Get outside or sit by a window first thing in the morning to kickstart your body’s internal clock. Even on a cloudy day, open the curtains and let the light in.

2. Unhealthy diet and lack of exercise

Ultra-processed foods and those high in sugar or refined carbohydrates – like white bread, cakes and pastries – can cause sharp spikes and crashes in energy levels throughout the day.

When paired with a low activity lifestyle, this can disrupt your body’s natural sleep-wake cycle and make it harder to fall or stay asleep.

Sleep hygiene tips:

Opt for a diet that’s rich in fruit, vegetables, wholegrains, and oily fish, while cutting down on saturated fat, salt, and added sugars to avoid energy dips.
Chicken, turkey and eggs all contain tryptophan – an amino acid that helps your body produce serotonin and melatonin which may help regulate sleep.
There are many ways to sneak more exercise onto your day like doing the gardening or having a spring clean. Get more exercise tips.

3. Too much caffeine

Not everyone is sensitive to caffeine, but if you’re sensitive or struggling to sleep it can make it difficult to fall asleep or interfere with your sleep cycle.

Sleep hygiene tip:

Try cutting off caffeine at around 2pm and switch to herbal alternatives like teas instead.

4. Too much screen time

Screens are another big culprit. It’s not just the blue light that keeps you awake; it’s the mental stimulation. Scrolling, news alerts, endless WhatsApp chats, they all keep your brain wired when it should be winding down.

Sleep hygiene tip:

Once you’re in the bedroom, do not pick up your phone again. Use this quiet time to wind down.

5. Busy at bedtime

Your body needs to wind down before sleep, so doing chores or watching TV straight before bed can stop you sleeping well.

Sleep hygiene tip:

Having a calm bedtime routine can really help. Find something that feels natural and enjoyable to you like meditation or reading a book.

6. Drinking alcohol

A glass or two of wine might help get you feel sleepy, but it also robs you of deep, restorative sleep.

You go through light sleep stages and miss out on the growth and repair that happens in deep sleep.

Sleep hygiene tip:

The NHS recommends drinking no more than 14 units of alcohol per week, which is about 6 pints of 4 per cent beer or 6 glasses (175ml) of 13 per cent wine.
There are a few simple tricks to sticking these limits such as drinking water between each drink to slow you down and keep you hydrated. Many pubs and supermarkets now sell alcohol-free drinks including lager, cider, wine and spirits – so try these instead.

7. Having a weekend lie-in

It might sound inviting to spend extra time between the sheets at the weekend to catch up on sleep you may have missed or top up your ‘sleep bank’, but sleeping in disrupts your body clock and creates ‘social jetlag’.

Sleep hygiene tip:

Keep your wake-up time consistent, even on weekends. It’s one of the simplest ways to strengthen your circadian rhythm and improve sleep quality.

The sleep cycle - 5 stages

When you’re asleep you go through 5 stages of sleep in a cycle many times in one night, going from light sleep to deep sleep and back again. Anything that disrupts this cycle, so you do not reach the deep sleep and dream sleep stages, can lead to poor quality sleep, which in turn can be harmful for your heart and circulatory system.

The first 4 stages are part of non-rapid eye movement (NREM) sleep, and the fifth is rapid eye movement (REM) sleep.

Stage 1 - Light sleep
This is the gentle drift-off phase, where you’re hovering between wakefulness and sleep. Your muscles relax, your breathing slows, and you can be easily stirred. It’s like dipping your toes into sleep.

Stage 2 - Deeper light sleep
Your heart rate slows and your body temperature drops. The brain starts producing sleep spindles - brief bursts of activity that help block out external noise and support memory. You’re settling in now.

Stage 3 - Deep sleep/slow-wave sleep
This is where the real physical recovery begins. Your body repairs itself, your immune system gets a boost, and growth hormones are released. It’s much harder to wake up from this stage, and that’s a good thing.

Stage 4 - Very deep sleep
Often grouped with stage 3, this is the most restorative phase of sleep. Tissue repair, cell regeneration, and hormone release are all in full swing. If you’ve ever felt groggy after being woken suddenly, you were probably in this stage.

Stage 5 - Dream sleep
Your brain lights up with activity, your eyes dart around behind closed lids, and your body becomes temporarily paralysed (so you do not act out your dreams). REM sleep is vital for emotional processing, learning and memory consolidation. It’s where your brain does its overnight housekeeping.

For more expert guidance on sleep visit thesleepcharity.org.uk

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