How insomnia affects your cardiovascular system^1,2

Most adults need 7 – 8 hours of sleep each night to maintain healthy body systems like the cardiovascular system (which includes the heart and blood vessels). Sleep plays a key role in most aspects of physical health, giving your body time to restore, recuperate and recharge.^3,4

Your body goes through various stages of sleep each night.⁵

During the NREM stages of sleep, your⁴:

• Heart rate slows down
• Blood pressure drops
• Breathing stabilises

These physical changes reduce stress on your heart, allowing it to recuperate from strain that your waking hours places on it.⁴
If you don’t get enough sleep (known as sleep deprivation or insufficient sleep) or if your sleep is frequently interrupted, you won’t spend enough time in the deep stages of NREM sleep that benefits your heart. Long-term (chronic) sleep deprivation can lead to several cardiovascular problems e.g. high blood pressure (hypertension), high cholesterol levels (hypercholesterolaemia), heart attack (myocardial infarction), obesity, diabetes and stroke.^3,4

Sleep deprivation can be caused by sleep disorders like insomnia, sleep apnoea, narcolepsy and restless legs syndrome. Insomnia is characterised by difficulty falling asleep, difficulty staying asleep, difficulties falling asleep and staying asleep, and/or waking up earlier than you intended to. As many as 1 in 2 adults experience short-term insomnia at some point in their life, and 1 in 10 may have long-term (chronic) insomnia.^1,2,3 Learn more about insomnia

The link between insomnia/sleep deprivation and hypertension (high blood pressure)^2,4
Your blood pressure drops by about 10 – 20 % during normal, healthy sleep. This process is referred to as nocturnal dipping. Lack of sleep or disruptions to your sleep interferes with nocturnal dipping, meaning that your blood pressure does not drop at night. Increased/elevated night-time blood pressure can lead to overall hypertension, increased risk of stroke and heart attack, kidney problems and reduced blood flow to your brain. The link between sleep deprivation and hypertension is the highest in middle-aged adults.

Insomnia and heart attacks (myocardial infarction)^1,4
Myocardial infarctions occur when blood flow, and thus oxygen supply, to your heart are blocked. They can be fatal as the disruption in oxygen supply can damage your heart. Sleep deprivation and insomnia increase the risk of myocardial infarction (MI). A recent study showed that people who suffer from insomnia were 69 % more likely to experience myocardial infarction compared to those who don’t have the sleep disorder. The risk for MI was highest in people who slept for 5 hours or less, compared to people whose sleep lasted 7 – 8 hours.^1,4

Cortisol, a hormone produced by the hypothalamic-pituitary-adrenal (HPA) axis in your body, is best known for its role in your response to stress. Sleep and the stress response both share the HPA axis pathway. NREM (non-rapid eye movement) sleep stages help your heart slow down and recuperate. REM (rapid eye movement) sleep involves heightened stress and activity. Insomnia can cause your body to produce more cortisol during the day (i.e. mimicking/activating a stress response). Increased levels of cortisol have been associated with an increased risk of myocardial infarction.^1,4,5

Sleep deprivation and coronary artery/heart disease⁴
Coronary artery/heart disease occurs as a result of atherosclerosis – a condition where plaque builds up in your arteries, causing them to harden and narrow, reducing the flow of blood and oxygen to your heart. Plaque formation can involve white blood cells, produced by your immune system as part of an inflammatory response. Poor sleep triggers chronic inflammation, which contributes to plaque formation and hardening of your arteries. In addition, raised blood pressure caused by sleep deprivation, can strain your arteries, making them less effective at bringing blood to your heart, thus contributing to heart disease.

Poor sleep and heart rate⁴
During normal sleep, your heart rate decreases during NREM sleep stages and then increases as you prepare to wake up. Poor sleep, including abrupt awakenings, can trigger a sharp increase in your heart rate, which together with an irregular heartbeat (also caused by sleeping problems) are associated with heart palpitations.

Sleep deprivation and stroke⁴
Strokes occur when the blood flow, and thus oxygen supply, to your brain is cut off, causing your brain cells to die. Ischaemic strokes occur when a blood clot or plaque blocks an artery in your brain. Transient ischaemic attacks (TIA) occur when the blockage is short-term. Studies have shown that lack of sleep increases your risk of having a stroke. As mentioned before, sleep deprivation increases your blood pressure, which is the leading risk factor for strokes. In addition, insufficient sleep contributes to plaque build-up in your arteries, making it easier for blockages to occur and cause ischaemic strokes or TIAs.

Get some sleep!⁴
Now that you know that sleep deprivation can harm your heart, it’s important that you prioritise getting good sleep. Some studies have shown that improving your sleep may reduce the risk of heart attacks (myocardial infarction) and other cardiovascular problems, especially if you are at high risk for those problems.

Speak to your doctor about heart-healthy sleep. Your doctor can develop an individualised plan to improve your sleep while addressing lifestyle factors e.g. diet and exercise, that are important for your heart and overall wellness.⁴

Disclaimer
In preparing this article, every effort has been made to provide an objective overview. The content contained in this article contains medical or health sciences information as per cited articles for public information. The content of this article has been initiated and is brought to you by Sanofi South Africa.