Everyone experiences the occasional sleepless night. But when the wide-eyed evenings persist for days, weeks, or months, it's time to consider contributing factors that may be increasing your risk.

Long-distance travel and late-night shifts

People that travel long-distance across multiple time zones, or are required to work night shifts or in the early morning, are at an increased risk for developing sleep problems. The body's circadian rhythm (24-hour biochemical, physiological, and behavioral cycle) is affected by frequent change in schedules. Disturbances in the circadian rhythm can lead to insomnia.

Stress

Everyday stress can cause temporary insomnia, while a major event, such as the death of a loved one or a divorce, can trigger chronic insomnia. It's important to identify the problems behind your anxiety, and seek treatment when needed.

Gender

Women are twice as likely to experience insomnia as men. Hormonal shifts during the menstrual cycle and in menopause are thought to be responsible for sleeplessness. Insomnia often occurs during perimenopause—the time leading up to menopause when night sweats and hot flashes commonly disturb sleep. Experts believe a lack of estrogen may contribute to sleep difficulties in postmenopausal women.

Learn more about hormonal changes that occur during menopause.

Age

Insomnia increases with age as our sleep patterns change. Older adults require less sleep at night, but often need to squeeze in an afternoon nap to ensure they are getting the recommended eight hours of sleep in a 24-hour period. Some estimates suggest that nearly half of all men and women over 60 experience symptoms of insomnia.

Mental disorders

Mood disorders, such as depression, anxiety, bipolar disorder, and post-traumatic stress disorder can all disrupt sleep. The severity and type of mood disorder can impact sleep in a variety of ways. It's common for people who suffer from clinical depression to wake early or have periods of restless sleep, while people who suffer from anxiety tend to be unable to fall asleep to begin with.

Find out more about mental health disorders.

Being overweight or obese

According to the Centers for Disease Control and Prevention, sleeping disorders are linked to obesity. Adults who sleep less than six hours a night have a significantly higher rate of obesity (33 percent) than those who sleep seven to eight hours a night (22 percent). This pattern was found in both men and women, and across all age and ethnic groups.