Sleep is one of the key elements to keeping our health intact, and researchers dedicate much of their time trying to understand its role in recovery processes.
Sleeping well has been found to reduce your risk for many health conditions, such as high blood pressure, heart disease and diabetes. Research funded by NHLBI indicates that sleeping less than 7-8 hours night increases your risks for these issues.
Sleep and Circadian Rhythms
Humans and most other vertebrates owe their sleep-wake cycle to an internal biological clock called a circadian rhythm. This daily cycle governs many biological functions including body temperature regulation and hormone release.
Sleep has evolved as a means to conserve energy when food was scarce and clear out waste products from our brains. Another theory suggests that it allows our minds to reorganize memories for long-term storage purposes as well as clear out waste products from memory cells.
Normal sleep EEG patterns feature large slow waves interspersed with short bursts of activity called spindles – thought to serve as an alert system that keeps the brain ready to wake up if necessary.
Why and how we sleep remain mysterious, but adequate amounts are linked to overall health and well-being. Individuals who don’t get enough rest are at higher risk of obesity, heart disease, stroke, depression and other disorders; and adequate rest is also key for strong immunity and memory function.
Sleep and the Brain
Sleep remains an elusive process, yet scientists are steadily improving our understanding of its impacts on both brain and body. When you fall asleep, your cells repair themselves as your heart rate slows and electrical signaling in the brain changes from alpha waves to theta waves.
Sleep can also help strengthen memories and develop pathways that drive creativity, according to research. Sleep also acts as a form of housekeeping by clearing away harmful molecules that build up in your brain during the day.
Lack of sleep can have serious health ramifications. Skipping out on quality restful zzzs increases your risk for disorders like high blood pressure, cardiovascular disease, diabetes and depression while weakening the body’s natural defenses against germs and sickness.
Sleep and the Immune System
People who do not get enough sleep, or whose restful slumber has been interrupted, can quickly notice how rejuvenating a good night of rest can be. Sleep supports overall bodily health including brain function and immune health.
In 1953, University of Chicago Professor Nathaniel Kleitman made a breakthrough when he and student Eugene Aserinsky devised an innovative method for recording brain’s electrical activity during sleep. Their research demonstrated that during each night of restful REM (rapid eye movement) sleep occurs, characterized by eyes moving behind closed lids while brain patterns closely resembling those experienced while awake.
Dreaming occurs during REM sleep, which also serves to strengthen immunity against infections and improve athletic performance. Studies have demonstrated that consistent and high-quality sleep reduces risk factors associated with obesity, high blood pressure and stable metabolism as well as improve immune responses for vaccines.
Sleep and the Heart
Scientists have made great advances in their study of sleep, yet are still trying to piece it all together. What knowledge we do possess makes clear, though, that getting sufficient restful restful restful is a critical element in health and well-being.
Sleep allows your body to conserve energy for the day ahead by shutting down most bodily systems and relaxing brain cells; this enables your body to conserve and store as much as possible for when food might become scarce in the evening hours. There has been speculation that this is an evolutionary adaptation; humans and other mammals likely relied upon this strategy when times were tougher to conserve energy reserves when resources were limited.
Other theories surrounding sleep include brain plasticity and restorative functions. Research indicates that getting sufficient restful sleep helps improve cognitive performance and repair damaged neurons; and sleep is linked with maintaining healthy weight and immune systems while decreasing risk factors associated with high blood pressure, heart disease, diabetes, depression and cancers.