People who could get by on four hours of sleep used to brag about their strength and endurance. Recent scientific studies, however, have shown us that a lack of sleep causes many significant changes in the body that can lead to obesity, disease, and even early death.

How much sleep do you need per night to stay healthy? How does insomnia put your health at risk? And if you're having trouble sleeping, how can you make your nights more restful?

Lack of Sleep Makes You Hungry
Several recent studies have shown that when you don't get enough sleep, your appetite increases, encouraging you to eat more and gain weight. Research from Uppsala University, for example, found that a single night of total sleep loss in young, normal-weight men resulted in increased levels of hunger. Using magnetic imaging (MRI) to examine the brains of 12 normal-weight males, scientists found that after a night of total sleep loss, the men showed a high level of activation in an area of the brain that controls the desire to eat.

"Bearing in mind that insufficient sleep is a growing problem in our modern society," said lead author Christian Benedict, "our results may explain why poor sleep habits can affect people's risk to gain weight in the long run." Benedict recommended that people sleep about eight hours every night to maintain a healthy body weight.

Too Little Sleep Affects Appetite Hormones
A study that recorded the sleep patterns of 9,000 people indicated that those who averaged only six hours of sleep per night were 27 percent more likely to be overweight than those who slept seven-to-nine hours. Study participants who averaged five hours of sleep per night were 73 percent more likely to be overweight.

How does a lack of sleep contribute to feelings of hunger? Scientists say that a lack of sleep leads to hormonal disturbances, causing the hormones leptin and ghrelin to get out of balance. When you are sleep deprived, your body produces too little leptin, the hormone that tells you you're full, and too much ghrelin, the hormone that tells you you're hungry. The next day, your hormones spur you to eat more and burn fewer calories. With all these hormones stacked against you, you'll likely find it extremely difficult to resist that morning paratha or afternoon piece of cake.

Sleeping for Less Than Six Hours May Cause Early Death
Researchers in the United Kingdom and Italy analyzed data from 16 separate studies conducted over 25 years, covering more than 1.3 million people and more than 100,000 deaths. They found that those who generally slept for less than six hours a night were 12 percent more likely to experience a premature death than those who consistently got six to eight hours sleep.

An earlier study showed similar results. Researchers found that people who reduced their sleep time from seven hours to five hours or less faced a 1.7-fold increased risk of mortality from all causes. Even worse, the risk of death from a cardiovascular problem doubled.

Findings indicated that consistently sleeping around seven hours per night is optimal for health.

Lack of Sleep Increases Risk of Other Diseases
Obesity and early mortality are just a couple of the potential problems associated with lack of sleep. A 2010 study found that those sleeping fewer than seven hours a night were at an increased risk of heart disease, with women under 60 who sleep five or fewer hours per night having twice the risk. A 2011 study found that people with type 2 diabetes who slept poorly at night had higher fasting glucose levels, insulin levels, and insulin resistance levels.

A Japanese study found that women who slept fewer than six hours a night had a 62 percent higher risk of breast cancer.

How to Get More Sleep?
Are you among the many people getting less than seven hours of sleep per night? Try adopting some of these practices to help you sleep better and longer:

  • Schedule: Make an effort to go to bed and wake up at the same time every day of the week, including weekends. This will help establish your body's regular sleep-wake cycle. It may help you to adopt the habit of doing the same things each night before bed, such as taking a warm bath or reading.
  • Sidestep Frustration: If you can't sleep after 15 minutes, get back up and do something that you find relaxing. Keep the lights low, read or listen to music, and only go back to bed when you're tired. Lying in bed frustrated makes it even harder to relax.
  • Say No to Stimulants: Caffeine, chocolate, and nicotine can keep you awake past your bedtime. Alcohol may make you feel sleepy initially, but will disrupt your rest later in the night. Stay away from these at least four hours before sleep.
  • Make it Comfy: Get the best mattress you can afford, and create a bedroom that invites rest. Use room-darkening shades, earplugs, a fan, or other tools that will help create a restful environment. Keep computers, televisions, and pets away.
  • Exercise: Being physically active during the day can help you fall asleep faster at night. Exercise also promotes deeper, more restful sleep. Just make sure you don't exercise too close to bedtime, since this can leave you too energized to sleep.
  • Relieve Stress: Stress can take a big toll on your sleep. If you find your mind running 160 km per hour as soon as your head hits the pillow, try adopting some stress-reducing techniques. Keep a journal by your bedside to write down what's bothering you. Start practicing yoga, learn to meditate, get regular massages, and take long walks. Once you've reduced your stress levels, you may find that falling asleep is as easy as closing your eyes.