With the growing prevalence of sleep-deprived individuals, research on the connection between sleep, hormones, and metabolism, among a myriad of other effects, has been growing rapidly. Several studies show that lack of sleep may have a significant impact on our metabolic, immune, and cardiovascular systems. Sleep disorders, including insomnia, contribute to the 30% of adults sleeping less than 6 hours a night.
The blame on diet and reduced physical activity for the rising rates of obesity and diabetes are not to be dismissed, however, the connection between metabolic derangements and sleep deprivation is also growing. To add insult to injury, researchers from St. Luke's-Roosevelt Hospital and Columbia University found that it’s not solely lack of sleep, but both length of time and percentage of overall sleep spent in various sleep stages that might be associated with decreased metabolic rate, increased hunger, and increased intake of calories (specifically from fat and carbohydrates).
According to a review found in the International Journal of Endocrinology, the body reacts to lack of sleep in the following ways:
1) Reduced glucose tolerance and insulin sensitivity – The rate at which sugar in the blood is taken into the cells was reduced by about 40% when sleep duration was altered. Prolonged elevated blood sugar and insulin resistance may lead to Type 2 Diabetes.
2) Altered appetite regulating hormones – Two hormones responsible for appetite regulation, leptin and ghrelin, may be negatively affected depending on sleep duration and quality. Leptin is produced in fat tissue and is released to suppress the appetite when the body has obtained enough fuel. Ghrelin on the other hand is secreted by the stomach in response to fasting and promotes hunger. Chemical changes occur during slumber and when these patterns are disrupted, ghrelin levels rise and leptin levels fall, resulting in an increase in hunger and appetite - a bad combination for weight management.
3) Inflammation and altered immune response – Sleep deprivation increases pro-inflammatory markers such as IL-6, TNF-α, and CRP. Over time, chronic inflammation and lack of free-radical fighting foods can lead to a suppressed immune system.
Sleep is restorative in nature and is critical to maintaining proper health.