Sleep remains one of the unsolved mysteries of science. One theory is that sleep slows energy consumption so that the brain can perform other important functions. If this does not happen, the body begins to burn energy at an alarming rate, much like a vehicle that has been poorly maintained.
Lack of Sleep Results in High Energy Consumption and Poor Performance
According to a study of energy consumption during sleep, the body sleeps to save energy for renewing and maintianing critical biological processes. When we are sleep deprived, we begin to expend large amounts of energy just to keep functioning.
The authors of the study explain that the body sleeps to conserve energy. When we bypass opportunities for quality sleep, we burn excess energy just to perform at minimal capacity.
Study Shows Sleep Deprivation Consumes Energy
The study by Christopher Jung and Emily Frydendall, entitled “Energy expenditure during sleep, sleep deprivation and sleep following sleep deprivation in adult humans,” (2010) focused on the cost of sleep deprivation in terms of energy expended by the body.
We know that the body expends less energy during sleep than during our daily activities. Jung and Frydendall also discovered:
- Sleep conserves more energy than previously thought.
- Sleep deprivation results in energy consumption at a much faster rate than normal.
Their research showed that one night without sleep costs the body the same amount of energy as a two-mile walk. Even though subjects were confined to bed rest during this tightly controlled study, their energy consumption rose 7% after 40 hours without sleep (24 hours of sleep deprivation).
Significance for Persons Who Have Sleep Disorders
On the first day of the study, subjects were allowed to sleep. Interestingly, the greatest amount of energy expended happened when subjects awakened by themselves, indicating a natural awakening or waking up due to a sleep disorder.
Persons with sleep disorders expend large amounts of energy when sleep is disrupted. In addition, lack of sleep requires them to expend much more energy than normal individuals to perfom the same tasks. The authors of the study urged more research on the cost of sleep disorders in terms of excess energy consumption during sleep and rapid energy consumption after a poor night's sleep.
Why the Body Sleeps to Conserves Energy
Jung and Frydendall believe that the body needs to enter into a state of energy conservation in order to harness the fuel needed to support other critical processes, such as replenishing immune system function, production of hormones and reinforcement of neurological pathways that enhance memory and learning.
The reasoning behind this is well documented. Sleep deprivation commonly demonstrates significant impairment in mental, emotional and cognitive health.
Purposeful Sleep Deprivation Not Recommended for Weight Loss
The researchers emphasized that sleep deprivation should never be used as a means of weight loss in the hopes of increased energy consumption. Facts from numerous studies show clearly that chronic sleep deprivation contributes to obesity.
Sleep deprivation significantly reduces stores of the hormone leptin, which signals feelings of satiety when we eat. Many studies show that sleep deprivation is associated with present and future weight gain.
Mystery of Why We Sleep: The Body Conserves Energy
If the body does not sleep, it must expend extra energy just to maintain minimal function. In simpler terms, we sleep because our body needs to rest. Sleep disorders are serious health problems. This study provides another path of research for understanding and treatment of sleep disorders.
Reference:
C. M. Jung, E. L. Melanson, E. J. Frydendall, L. Perreault, R. H. Eckel, K. P. Wright. Energy expenditure during sleep, sleep deprivation and sleep following sleep deprivation in adult humans The Journal of Physiology, 2010; 589 (1): 235 DOI: 10.1113/jphysiol.2010.197517
