How Your Sleep Affects Your Heart

Of all the reasons to get a good night's sleep, protecting your heart might not be top of mind. 

But maybe it should be. Sleep duration has decreased 1.5 to 2 hours per night per person in 

the last 50 years. But several recent studies show links between shortened sleep duration, 

defined as less than six hours of sleep, and increased risk of heart disease.

Sleep Loss and Heart Disease

One 2008 study  found a link between shortened sleep and increased coronary artery 

calcification (calcium deposits), "a good predictor of subsequent coronary artery disease," 

says researcher.

The study also revealed that shorter sleep predicted worsening hypertension (high blood 

pressure). "For most people, blood pressure falls at night," she says, "so it could be that 

with shorter sleep it's just not enough for that dip to take place."

But can you reverse this trend? Researchers aren't sure. Part of the reason is that sleep's 

effects on the heart are a relatively new area of study. Another is that measuring sleep is 

complicated. Many sleep studies rely on self-reporting, which may not always be accurate. 

Having your sleep measured objectively involves wearing an activity monitor, which "very 

likely changes your usual sleep," .

Bottom line? "It's pretty safe advice for the majority of people that sleeping less than six 

hours a night is probably not good," .

How Sleep Helps the Heart

How can getting enough sleep protect your heart?

Good-quality sleep decreases the work of your heart, as blood pressure and heart rate go 

down at night.

People who are sleep-deprived show less variability in their heart rate, meaning that instead 

of fluctuating normally, the heart rate usually stays elevated. "That is not a good sign," . 

"That looks like heightened stress."

Lack of sleep can increase insulin resistance, a risk factor for the development of type 2 

diabetes and heart disease.

Shortened sleep can increase CRP, or C-reactive protein, which is released with stress and 

inflammation. "If your CRP is high, it's a risk factor for cardiovascular and heart disease," . 

Shortened sleep also interferes with appetite regulation. "So you may end up eating more 

or eating foods that are less healthy for your heart," .