Men and women experience different sleeping patterns that affect brain activity and thus can influence their level of insomnia.

An estimated 35 million Americans suffer from long-lasting insomnia, says EHealthMD.

Insomnia has been found to be more common among females than males due to the relative size of the hypothalamus and its response to hormones.

Hormonal changes that occur during a woman's menses or menopause can alter sleep patterns, says Women's Health. When a woman's reproductive cycle undergoes perimenopause, the phase between menses and menopause, the body produces less and less estrogen and progesterone. Symptoms like hot flashes and night sweats can cause difficulty sleeping.

Pregnancy can also alter sleep patterns because of physical, emotional, and hormonal discomfort. Restless Legs Syndrome (RLS) is common among women who are pregnant in the third trimester, says Helen A. Emsellem, MD, Director of The Center for Sleep & Wake Disorders.

And size does matter. A man's hypothalamus tends to be twice as large as a woman's. The hypothalamus affects the connection between the eyes and the brain, and controls the synchronization of the "circadian period," commonly known as "body clock." For men this period lasts 24 hours, 11 minutes, which is six minutes longer than that of women, reports a study from the American Academy of Sleep Medicine.

In the study, which tracked 157 healthy participants, more men than women had body clocks longer than 24 hours and thus were compelled to go to sleep later and get up later. Twice as many women were reported to have shorter body clocks, with durations of less than 24 hours, and tended to go to bed and get up earlier.

Jeanne F. Duffy, the lead author of the study and an associate professor of medicine at Harvard Medical School, attributed women's shorter body clocks to it being difficult for women to stay asleep at the end of the night and stimulated symptoms of insomnia.

If a body clock is out of sync, sleep deprivation is likely. To prevent sleep deprivation, the study advised that people who have a body clock shorter than 24 hours increase light exposure at night and reduce it in the morning, whereas those with a longer body clock should reduce light at night and increase it in the morning.

Fifty percent of women who suffer from insomnia are likely to have glucose metabolism in certain areas of their brain, reports the Proceedings of the National Academy of Sciences of the United States of America (PNAS). The active brain activity does not permit a full night's rest for females.

The myth of catching up with sleep on weekends has been debunked by Dr. Duffy, who affirms it will just further push the biological clock out of sync.