The Science of Sleep: Why You Need 7-8 Hours a Night
No Sleep Means Poor Health
Getting by on four hours of sleep isn’t a testament to your physical strength and endurance. In fact, insufficient sleep detracts from your overall well-being. Lack of sleep can lead to obesity, increased risk of heart disease, and even early death. Read on to learn about the importance of quality sleep, and what happens when you don’t get it.
Lack of Sleep Makes You Hungry
Without enough sleep, your appetite increases, encouraging you to overeat and gain weight. Research from Uppsala University found that a single night of total sleep loss in young, normal-weight men resulted in increased hunger. Brain MRIs of 12 normal-weight males revealed that after a night of total sleep loss, an area of the brain that controls the desire to eat showed a high activation level.
Lead author Christian Benedict recommended eight hours of sleep nightly to maintain a healthy weight.
Less Sleep = More Weight
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. The research suggests that sleep may be an important tool for weight control.
Haywire Appetite Hormones
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 donut or afternoon candy bar.
The Threat of Early Death
Researchers in the United Kingdom and Italy analyzed 16 studies conducted over 25 years, covering more than 1.3 million people and 100,000 deaths. Those who slept for less than six hours a night were 12 percent more likely to experience premature death than those who consistently got six to eight hours’ sleep. These findings confirm an earlier study that showed that people who reduced their sleep from seven hours a night to five hours or less faced a 1.7-fold increased risk of mortality from all causes.
Greater Heart Disease Risk, More Diabetes Complications
Obesity and early mortality are not the only 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.
Sleep Deprivation May Raise Risk of Breast Cancer, Polyps
Here are more reasons to make a good night’s sleep part of your health regimen. A Japanese study found that women who slept fewer than six hours a night had a 62 percent higher risk of breast cancer. Additionally, a 2011 study from Case Western University found that those who slept fewer than six hours a night were 47 percent more likely to have colorectal polyps, which can become cancerous.
How to Get More ZZZ's
Try these tips if you’re short on sleep:
- Schedule. Go to bed and wake up at the same time every day, including weekends.
- Sidestep frustration. If you can't sleep after 15 minutes, get back up and do something relaxing. Read or listen to music, and go back to bed when you're tired.
- Banish stimulants. Caffeine, chocolate, and nicotine can keep you awake. Alcohol may make you feel sleepy initially, but will disrupt your rest later. Avoid these for at least four hours before sleep.
Set Yourself Up for Sleep
Prepare for your good night’s sleep with the following measures:
- Make it comfy. Get the best mattress you can afford, use shades, earplugs, and a fan to create a restful environment. Keep electronics and pets away.
- Exercise. Physical activity during the day can help you fall asleep faster at night.
- Relieve stress. If your mind races when your head hits the pillow, keep a journal by your bedside to note what’s bothering you. Yoga, meditation, regular massages, and long walks also may help.
Make Sleep a Priority
The science is clear: getting a good night's sleep is a key component of good health. Without sleep, our bodies become weary, face increased hunger, and crave unhealthy foods. By following a few simple steps—like scheduling your bedtime and avoiding coffee at night—you will be well on your way to enjoying longer, more restful nights. Remember, sleep is not a luxury—it is a health necessity.
- Benedict, C. et al. (2012, March). Acute Sleep Deprivation Enhances the Brain's Response to Hedonic Food Stimuli: An fMRI Study. The Journal of Clinical Endocrinology & Metabolism, 97(3), E443-E447. Retrieved June 25, 2013, from http://jcem.endojournals.org/content/97/3/E443.short
- Cappuccio, F.P. et al. (2010). Sleep Duration and All-Cause Mortality: A Systematic Review and Meta-Analysis of Prospective Studies. Sleep, 33(5), 585-592. Retrieved June 25, 2013, from http://www.journalsleep.org/viewabstract.aspx?pid=27780
- Ferrie, J.E. et al. (2007). A prospective study of change in sleep duration: associations with mortality in the Whitehall II cohort. Sleep, 30(12), 1659-1666. Retrieved June 25, 2013, from http://www.journalsleep.org/ViewAbstract.aspx?pid=27004
- Gangwisch, J.E. et al. (2005, October). Inadequate sleep as a risk factor for obesity: analyses of the NHANES I. Sleep, 28(10), 1289-1296. Retrieved June 25, 2013, from http://www.ncbi.nlm.nih.gov/pubmed/16295214
- Kakizaki, M. et al. (2008, November 4). Sleep duration and the risk of breast cancer: the Ohsaki Cohort Study. British Journal of Cancer, 99(9), 1502-1505. Retrieved June 25, 2013, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2579702/
- Knutson, K.L. et al. (2011, March 16). Cross-Sectional Associations Between Measures of Sleep and Markers of Glucose Metabolism Among Subjects With and Without Diabetes. Diabetes Care, 34(5), 1171-1176. Retrieved June 25, 2013, from http://care.diabetesjournals.org/content/34/5/1171.full
- Sabanayagam, C. & Shankar, A. (2010). Sleep duration and cardiovascular disease: results from the national health interview survey. Sleep, 33(8), 1037-1042. Retrieved June 25, 2013, from http://www.journalsleep.org/ViewAbstract.aspx?pid=27857
- Thompson, C.L. et al. (2011, February 15). Short duration of sleep increases risk of colorectal adenoma. Cancer, 117(4), 841–847. Retrieved June 25, 2013, from http://onlinelibrary.wiley.com/doi/10.1002/cncr.25507/full