London: Men find it more difficult to fall into very deep sleep than women, which puts them at the risk of heart attacks and high blood pressure, says a new study.

Researchers at Harvard University have also found that men are more likely to get up during the night – sometimes due to their own snoring -- and consequently get fewer hours of deep uninterrupted sleep, known as "slow-wave sleep".

According to them, hose who get less of this type of sleep are more prone to suffer from high blood pressure, which can lead to heart attacks and strokes, the 'Daily Mail' said.

The study, published in the journal of the American Heart Association, looked at the sleeping habits of 784 men over 65. At various intervals, the researchers measured the quality of their sleep, levels of brain activity during sleep, and how often they woke at night.

The researchers found that men who had the least amount of deep sleep were 80 per cent more likely to develop high blood pressure. These males spent just four per cent of their sleeping time in deep sleep, compared with an average person's level of 15 per cent.

They say men's trouble with deep sleep could be because they are more likely to suffer from a condition called sleep apnoea, which is characterised by breathing problems and loud snoring.

Lead researcher Susan Redline said: "Our study shows for the first time that poor-quality sleep, reflected by reduced slow-wave sleep, puts individuals at significantly increased risk of developing high blood pressure.

"Although women were not included in this study, it's quite likely that those who have lower levels of slow-wave sleep for any number of reasons may also have an increased risk of developing high blood pressure."

Natasha Stewart, of the British Heart Foundation, added: "We would need to see more research in other age groups and involving women to confirm this particular association.