The exact number of hours’ sleep you need to dodge killer heart disease revealed

It’s widely believed that eight hours is the magic number when it comes to getting adequate sleep.

But now scientists have found that you can lower your risk of heart disease by spending fewer hours in bed.

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US researchers found that people whose kip was limited to five hours had higher blood pressure and heart rates — even when they made up for it over the weekend.

You should aim to get more sleep each day to avoid the deadly condition in the long term, they suggested.

dr Anne-Marie Chang of Penn State University said: “There is a lot of evidence that this sleep deprivation is linked to cardiovascular disease in the long term.

“Our research uncovers a possible mechanism for this association.

“Improving your cardiovascular health on a regular enough basis when you’re young could make your heart more susceptible to cardiovascular disease in the future.”

According to the British Heart Foundation, around 7.6 million Britons are living with a heart or circulatory disease.

High blood pressure can increase your risk of heart disease because it damages your arteries by making them less elastic and reducing the flow of blood and oxygen to your heart.

The NHS recommends adults get seven to nine hours of sleep, while children need nine to 13 hours.

Previous research has shown that your blood pressure goes down when you sleep – and when you’re not sleeping, it stays higher for longer.

The latest study published in psychosomaticsexamined how this builds up over consecutive days and the effects of sleep on heart rate.

Researchers took blood pressure and heart rate measurements every two hours for 11 days in 15 healthy men aged 20 to 35.

In the first three nights, they were allowed to sleep for 10 hours to return to baseline sleep levels.

They were then restricted to five hours a night for five nights, followed by two recovery nights, during which they were allowed to sleep 10 hours again.

Heart rate increased by almost one beat per minute on average for each consecutive day.

The average baseline heart rate was 69 beats per minute, while the average heart rate at the end of the study on the second day of recovery was nearly 78 beats per minute.

The systolic blood pressure also rose by about 0.5 millimeters of mercury per day.

The mean systolic blood pressure at baseline was 116 mmHg and was almost 119.5 mmHg at the end of the recovery period.

Lead author David Reichenberger said, “Both heart rate and systolic blood pressure increased with each subsequent day and did not return to baseline at the end of the recovery period.”

“Although they had additional opportunities to rest, their cardiovascular systems still had not recovered by the end of the study weekend.”