CARDIOVASCULAR SYSTEM…

“Lack of sleep puts you at risk of metabolic syndrome,” says Dr Keay. This is the medical term for a combination of diabetes, high blood pressure and obesity. While we’ve already seen how lack of sleep can be correlated with an increased risk of diabetes and obesity, you’re also more likely to suffer from high blood pressure if you have disrupted sleep. This is partly because blood pressure naturally falls while we’re asleep, but also because raised levels of cortisol can speed up your heart and raise your blood pressure. Add in the fact that chronic sleep deprivation can lead to increased levels of inflammation, which results in a build-up of deposits in the arteries – and thus higher blood pressure – and you can see the problem.

According to the NHS website, while “on their own, diabetes, high blood pressure and obesity can damage your blood vessels, having all three together is particularly dangerous [and] puts you at greater risk of getting coronary heart disease, stroke and other conditions that affect the blood vessels”.

In fact, one study found that people who slept less than seven hours per night had an elevated risk of heart failure, while another identified that those sleeping less than six hours per night had a 20 per cent higher chance of a heart attack.