From chronic illness to weight gain, research shows that lack of sleep can cause a host of health problems. Sleep experts share why it's important to get a good night's rest. Plus, tips on how you can sleep better.

It's no secret that a lousy night's sleep makes you feel lousy, too. The latest scientific findings tie disrupted slumber to everything from chronic diseases to obesity and depression. Beyond a doubt, adequate rest is essential for both emotional and physical well-being.

Helen Driver, assistant professor in the department of medicine at Queen's University and a somnologist at Kingston General Hospital's Sleep Disorder Lab, has studied the science of sleep since the late 1980s. "The interest level for the subject has gone way up," she says. "Recently, there has been a collective realization about how tired we feel, and there's a desire to know what can be done about it."

Researchers are working to find out more. In a study published in the journal Sleep, 24 percent of Canadians age 15 and up experienced insomnia (the inability to get to sleep or stay asleep). And, according to Driver, women are more likely to experience insomnia and complain about fatigue because they aren't getting the seven to eight hours they need.

Research shows that, during sleep, your brain is a beehive of activity, helping to produce hormones like melatonin and growth hormone, which play a part in repairing cells, processing new information, reducing inflammation, regulating emotions and building memory. The brain also cleans house regularly, flushing away toxins like excess protein through the glymphatic system—a kind of plumbing for the brain. In fact, in studies with mice, the glymphatic system was 10 times more active during sleep. Scientists at the University of Rochester Medical Center believe this process may help maintain healthy brain cells, and might even keep Alzheimer's and Parkinson's disease at bay.

The health effects of sleep deprivation
A host of health issues can result from inadequate sleep. Feeling stressed out, for example, isn't just a product of an over-loaded schedule or a hectic lifestyle. Among the chronically sleepless, cortisol (the stress hormone) remains at high levels instead of dropping in accordance with the body's circadian rhythm, the natural body clock that controls physiological processes like sleep. The body's resulting inability to regulate cortisol potentially contributes to high blood pressure and can increase the risk of calcification of the coronary arteries.

Elevated cortisol levels in the evening are also linked to the development of insulin resistance, a precursor to obesity and diabetes. In one study, healthy young men who were sleep-deprived for less than a week developed a prediabetic state of impaired glucose tolerance. Furthermore, there is growing evidence that those with sleep apnea also have a higher risk of developing Type 2 diabetes, even after taking into account other contributing risk factors like obesity, age and waist circumference.

Shortchanged sleepers may also have difficulty maintaining a healthy weight. Two key hormones involved in appetite regulation can misbehave on too little sleep—ghrelin, responsible for stimulating appetite, rises, while leptin, which signals satiety, drops. Researchers at the Stanford University School of Medicine have found this specific hormone cocktail increases salt and fat cravings, and may make individuals more prone to obesity.

Inadequate sleep may also be linked to chronic illnesses like cancer and heart disease. Though the connection between sleep disorders and disease is not entirely understood, a lack of sleep may increase inflammation throughout the body and impair cell repair. For women getting fewer than six hours of sleep nightly, the risk of coronary heart disease rises substantially.

Your monthly flow might not be helping, either. Sixty-seven percent of women say they lose sleep due to their menstrual cycle. Backaches, headaches, breast tenderness and pelvic pain cause discomfort, while fluctuating hormones contribute to sleeplessness. "After the age of 35, our ovaries begin to age, causing lower levels of progesterone," says Dr. Nishi Dhawan of Vancouver's Westcoast Women's Clinic. "As perimenopause approaches, estrogen and progesterone production become more erratic, which may cause anxiety and insomnia." Dr. Bal Bawa, also of the Westcoast Women's Clinic, adds that menopause can be experienced differently. Some women say they've never slept better, but for the majority, the ability to sleep worsens.

Lastly, sleep is important for immune system function. People who don't get enough shut-eye are less able to fight infection.The stats are sobering: Sleeping fewer than five hours increases the risk of death by about 15 percent.

"Adequate sleep is not a luxury," says Driver. "We need to make it a priority. We need to raise kids that have healthy bedtime routines, so they can grow up to be adults who give credence to sleep's crucial role in our health."

How did sleep cycles get so out of whack? Driver points to modern technology as a prime culprit. Prior to having electricity in the home, the body's circadian rhythm dictated sleep patterns. Light was a powerful timekeeper—in the morning, sunlight coaxed people awake and at sundown, it was time to hit the hay. Today, simply by switching on a light at night, our bodies are pressured to stay alert and awake, as opposed to following their natural rhythm.

The prevalence of electronic devices makes the situation even worse. When laptops, tablets and smartphones enter the bedroom, problems arise. "The blue light they emit confuses the body," says Driver. "It's stimulating and disturbing, leading to an ‘on call' type of lighter sleep that is not deep or fully restorative, as seen with moms listening for a baby's cry and doctors poised to answer an emergency call."

How to improve your sleep hygiene
Total darkness in the bedroom is recommended by the experts, as it promotes higher secretions of melatonin—which encourages sleepiness, regulates body temperature and blood pressure, and inhibits cancer cell growth. Conversely, light exposure suppresses melatonin. Several studies have linked light during nighttime hours and shift work with an increased incidence of breast cancer. Turning off electronics an hour before bedtime and keeping devices away from sleep zones go a long way toward encouraging more restorative sleep.

Surprisingly, interrupted sleep can be just as bad as getting no sleep at all. A pilot study from Tel Aviv University concluded that when sleep was disrupted during the night, even when participants slept seven hours, it was equivalent to sleeping half that time—causing the same fatigue, depression and confusion experienced by the severely sleep-deprived. The most crucial time is the deep slumber that occurs during the third stage of the sleep cycle. This is when the body goes into overdrive to produce healing and repairing hormones.

Thankfully, the body is properly equipped to make up for a few nights of poor sleep: "It's intelligent in creating homeostasis—so the body will try to compensate," says Dr. Bawa. But if you're exhausted to the point where energy levels don't bounce back after a couple nights of solid sleep, and normal activities are affected, it's time to see a doctor. "We look at a range of factors, like adrenal gland fatigue, anemia and thyroid hormone disruption, for underlying causes of fatigue," she says.

Getting a good night's sleep is about more than just feeling rested—it's about building a healthy foundation for your future.