Most everyone knows about the benefits of a healthy diet and regular exercise, but many overlook the important role of sleep. Sleep is a key to good health and should be considered—said two neurologists at Northwestern University in an editorial of the Journal Archives of Internal Medicine—as “essential to a healthy lifestyle as exercise and nutrition.” If you do not improve your sleep (especially your nightly sleep) you will not get the maximum benefits from your exercise and diet.

In fact, lack of proper sleep can have many negative consequences for the brain and body, including slowed brain function and increased rates of disease and mortality. For optimal functioning, we must allow our minds and bodies the opportunity to take advantage of the restorative and rejuvenating effects of regular sleep.

A study conducted at the University of Chicago found that chronic sleep loss could hasten the onset and increase the severity of diabetes, high blood pressure, and obesity. Lack of sleep is also linked to a significantly increased risk of coronary heart disease. Not enough sleep can also result in excessive daytime sleepiness, reduced neurocognitive function, and depression. There is also evidence for a decrease in memory and learning.

Research presented at the 1993 annual conference of the World Federation of Sleep Society reported that losing three hours of sleep on any given night can cut the effectiveness of an individual’s immune system in half. Lack of sleep is also associated with a decreased ability to perform tasks controlled by the frontal lobe, such as planning, concentration, motor performance, and high-level intellectual skills. In schoolchildren, sleep restriction has been shown to contribute to increased attention problems; in college age students, sleep restriction negatively impacted academic measures in contrast to those who had a better quality of sleep. An international survey of nearly 17,500 university students from 24 countries found that not getting enough sleep or sleeping less than seven hours nightly was related to poorer self-reported health in young adults.

One somewhat scary fact about sleep deprivation is that individuals who were sleep deprived for 14 days reported feeling only slightly sleepy; that is—they were unaware of how impaired they really were! The cognitive performance deficits included reduced ability to pay attention and to react to stimulus such as when driving or monitoring security at airports. Other deficits involved impairment of the ability to think quickly and avoid mistakes, as well as a reduced ability to multitask. The risk for other serious types of accidents is, of course, increased as well. “Large-scale disasters like Chernobyl, the Exxon Valdez crash, and the Three Mile Island incident all occurred in early pre-dawn hours, a time when vigilance is at a low point.” In each of these devastating, man-made tragedies, lack of sleep and rest were a major factor.

If you’ve been a night owl, do yourself a favor and go to bed a little bit earlier. Get the type of restorative rest that will improve your clarity and performance!