15th March 2024

How does sleep affect your heart health?

Sleep is a fundamental component of your overall wellbeing as it allows your body and mind to rest and continue supporting the body’s functions. Similarly to exercise and a healthy balanced diet, making sure you get enough sleep during the night may help prevent a range of health problems. According to the Irish Heart Foundation, it is recommended that adults get between seven and nine hours of sleep per night.

But what exactly is the link between sleep and heart disease? Lack of sleep has a domino effect on all aspects of our lives, including lack of energy to exercise, hormonal imbalance leading to unhealthy cravings, and increased stress levels. Additionally, it may lead to elevated blood pressure and coronary artery disease: 

  • Blood pressure: during sleep, your blood pressure drops by around 10-20%*, allowing the heart to relax by reducing the amount of pressure and stress built up throughout the day. Elevated nighttime blood pressure is tied to overall hypertension (high blood pressure). 
  • Coronary artery disease: when blood pressure doesn’t dip at nighttime, and arteries do not have the time to relax, they can become inflamed and cause plaque to build up. Plaque build-up within arteries causes them to narrow, making it more challenging and strenuous to pump blood to the heart, leading to several cardiovascular conditions including coronary artery disease, heart failure, heart attacks and stroke. 

One of the potential causes leading to sleep issues and constant fatigue can be a disruption within the circadian rhythm, or internal body clock. 

What is circadian rhythm and how does it affect sleep? 

Circadian rhythm is your body’s internal 24-hour clock that regulates functions within the body. The circadian rhythm is most commonly associated with sleep and the sleep-wake cycle. This internal clock is directly influenced by environmental factors such as daylight. When you wake up in the morning, the rising sun helps you awaken and start the day, whereas at night the reduction in light initiates the production of melatonin, a hormone that triggers your body to feel tired and fall asleep. 

When the circadian rhythm becomes disrupted, the body’s ability to fall asleep, stay asleep and have a good quality of sleep is affected as a result. 


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What are some tips for getting a good night’s sleep? 

If you think that your circadian rhythm, and in particular the sleep-wake cycle, is disrupted there are a number of things you can do to help you get a good night’s sleep, including:

  • Establish an evening routine: by having a consistent evening routine, you are signalling to your body that it is time to sleep. Your routine may include having a relaxing bath or shower, reading, and turning off electronic devices. Having a set bedtime and wake time during the week and at the weekends will also help your body recognise when it is time to wake up and when the production of melatonin can begin to help you feel tired. 
  • Create a good sleeping environment: ensuring that your sleeping environment is dark, quiet, and not too cold or hot can help you get a good night’s sleep. 
  • Limit caffeine and alcohol: caffeinated drinks and alcohol are stimulants and may affect your ability to fall asleep, cause disruption to the quality of sleep and increase the need to urinate at night. 
  • Limit screen time: blue light emitting from the screens of our phones, tablets, computers, and TVs mimics daylight and therefore interrupts the production of melatonin, disrupting the circadian rhythm. The content you consume may also have an effect on you, especially if you are looking at something that’s causing you to feel stressed or anxious. 
  • Exercise: physical activity is a good way to contribute to your heart health, maintain a healthy weight, relieve stress, and help you get a good night’s sleep. 
  • Stress management: stress can make it more challenging to sleep as you may be actively thinking about things that are causing you stress, preventing your mind from winding down. If you are not getting enough sleep, this can lead to your stress levels rising throughout the day, creating a loop effect. Taking the time to relax before bed can help you lower your stress levels which will have a positive effect on your sleep. 
  • Avoid eating before bed: consuming food shortly before going to sleep can disrupt the circadian rhythm as your body will begin digestion and production of insulin to break down the meal, rather than focusing on the production of melatonin that helps you fall asleep. It is advised to consume your last meal around three hours before bedtime to allow your body enough time to digest the food. 

If you are employing the above techniques and still struggle with getting a good night’s sleep, we advise you to contact your GP as a lack of sleep can impact your physical and mental health.


The above content was reviewed by Dr. Rory Durand, Cardiology Fellow at the Cardiovascular Research Institute (CVRI) in Dublin. 

*Source: Cleveland Clinic 

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