It's official: Women ARE grumpier than men in the mornings Women are more angry and hostile if they get insufficient sleep, say North Carolina scientists Sleep deprivation also increases women's risk of heart disease, stroke and depression But a man's health is barely affected by lack of sleep If the woman in your life woke up grumpy this morning, don't be too hard on her. It is, apparently, only natural. Scientists have discovered that women need more sleep than men. And chances are, she's not getting enough. In fact the best thing a loving husband or partner can do is perhaps persuade her to get a few extra hours snuggling under the duvet. Or face the consequences. Researchers in the U.S. found that women suffer more than men, both mentally and physically, if they are forced to go without sufficient sleep Scientists say women suffer more than men, both mentally and physically, if they are forced to skimp on their sleep. As well as a higher risk of heart disease, depression and psychological problems, sleep-deprived women have extra clotting factors in their blood, which can lead to a stroke. They also have higher inflammation markers, which indicate developing health problems. As inflammation markers are also linked to pain, sleep expert Dr Michael Breus explained that women can literally be in more pain when they wake up. That's enough to make any girl feel rather grumpy. By contrast, the state of a man's health does not appear to be closely linked to how much he sleeps. In the study, carried out by scientists at Duke University in North Carolina, men showed no increased risk of developing the ailments that affect women when they are losing sleep. According to Dr Breus, sleep-deprived women are angrier, more hostile and more aggressive "We found that women had more depression, women had more anger, and women had more hostility early in the morning," said Dr Breus. If this sounds like someone you know, it can probably be blamed on sleep deprivation and the fact that women are particularly susceptible to the effects. What does Dr Breus advise? If you don't manage to get enough sleep at night, try taking strategic naps. However, he warned that those naps should be either 25 minutes or 90 minutes long. Any other length will make the snoozer feel worse when they wake, he said. This is not the first time experts have suggested that women need more sleep than men. One of Britain's leading authorities on sleep found that women actually need 20 minutes more shut-eye. This is because of the female multi-tasking brain. "One of the major functions of sleep is to allow the brain to recover and repair itself," said Professor Jim Horne, director of the Sleep Research Centre at Loughborough University. During deep sleep, the cortex - the part of the brain responsible for thought, memory, language and so on - disengages from the senses and goes into recovery mode. The more of your brain you use during the day, the more of it that needs to recover and, consequently, the more sleep you need. Women tend to multi-task - they do lots at once and are flexible - and so they use more of their actual brain than men do. Because of that, their sleep need is greater. A man who has a complex job that involves a lot of decision-making and lateral thinking may also need more sleep than the average male - though probably still not as much as a woman.