Women really sleep worse than men, research shows.
And scientists think this is because their body clock runs about six minutes faster.
This means they are out of sync with their environment, which wreaks havoc on their internal wiring that tells their brain when to feel sleepy.
An all-female team of experts based at Harvard, Stanford and Southampton universities reviewed dozens of scientific papers published over the past decade about the poorly understood “sleep gap” that exists between men and women.
Many used actigraphs, wrist-worn digital devices similar to Apple watches or Fitbits, that monitor heart rate and sleep patterns.
An all-female team of experts, based at Harvard, Stanford and Southampton Universities, reviewed dozens of scientific papers published over the past decade about the poorly understood ‘sleep gap’ that exists between men and women
The results showed that women were almost 60 percent more likely to have insomnia.
They rate their sleep quality lower than men and complain that they get bad nights more often.
Men, meanwhile get less restorative, deep sleep than women and are more likely to be night owls. In addition, they were more likely to have sleep apnea.
Deeper experiments also revealed that there were differences between the sexes in terms of the speed of their body’s built-in clock, or circadian rhythm, which sets the rhythm of our lives.
When it comes to sleep, the body responds to environmental cues to lower our core temperature in the hours before we close our eyes to prepare our bodies for sleep.
Internally, the body also secretes more melatonin, a hormone that helps us fall asleep.
Research in the new analysis found that melatonin is secreted earlier in women than in men.
Core body temperature apparently followed the same pattern, with an earlier peak in women.
Researchers said their findings, published in the journal Sleep Medicine Reviews, illustrate the “critical role sex plays” in sleep and health.
Study author Dr Renske Lok, an expert in psychiatry based at Stanford, said: ‘Although this (six minute) difference may be small, it is significant.
‘The misalignment between the central body clock and the sleep-wake cycle is approximately five times greater in women than in men.
‘Imagine if someone’s watch was constantly running six minutes faster or slower.
‘Over days, weeks and months, this difference can lead to a noticeable misalignment between the internal clock and external signals, such as light and darkness.’
Dr. Lok added: ‘Disruptions in the circadian rhythm have been linked to several health problems, including sleep disorders, mood disorders and reduced cognitive function.
‘Even small differences in circadian periods can have significant consequences for overall health and well-being.’
Fellow author Dr Sarah Chellappa, a neuroscientist at Southampton, added: ‘Lower sleep quality is associated with anxiety and depressive disorders, which are twice as common in women as in men.
‘Women are also more likely than men to be diagnosed with insomnia, although the reasons are not entirely clear.’
One study reviewed found that women were up to four times more likely to develop a sleep-related eating disorder, in which people eat repeatedly during the night.
Another found that they had a 25 to 50 percent higher chance of developing restless leg syndrome.
Linked to iron deficiency, the condition creates an eerie feeling in the legs and an irresistible urge to move them, which can keep patients awake at night.
Women typically slept longer than men and spent about eight minutes more in non-rapid eye movement (non-REM) sleep.
Lack of sleep can lead to obesity, memory loss, diabetes, heart disease, heightened and unstable emotions, reduced learning ability and a reduced immune response, leaving you vulnerable to disease
About 80 percent of adult sleep is non-REM sleep, although only 20 percent of this is deep sleep. The other type of sleep is known as rapid eye movement sleep and is the period when vivid dreams occur.
During the deepest phase of deep sleep, brain waves are much slower and this is the time when growth hormone is released. The body uses this to repair and regrow tissues, build bones and muscles, and strengthen the immune system.
Although time spent in non-REM decreases with age, researchers noted, this decline is more substantial in older men.
Men also tended to overeat more than women in response to sleep loss, researchers said.
Writing in the diary, Sleep Medicine ReviewsAccording to researchers, understanding sex differences during sleep is “essential for tailoring sleep medicine” and combating sleep disorders.
However, many of the studies failed to assess how biological differences, such as during the menstrual cycle and menopause, affect sleep patterns, they noted.
Previous research has suggested a link between sleep deprivation and an increased risk of obesity and type 2 diabetes.
The most common causes of insomnia are anxiety, depression, alcohol, caffeine, recreational drugs and shift work.
While adults need between seven and nine hours of sleep, children are advised to sleep between nine and 13 hours, the NHS advises.
The health care industry estimates that it takes most people an average of fourteen minutes to fall asleep.
Research shows that at least 30 percent of the problems encountered by general practitioners are directly or indirectly related to sleep.
Yet only one in ten Britons talk to their doctor about insomnia, despite 30 percent taking medication to deal with it.