Studies suggest that people who sleep less are more likely to have a higher body mass index (BMI) and develop obesity. Sleep affects the levels of two hormones, leptin and ghrelin, which control feelings of hunger and fullness. Leptin tells the brain we have had enough to eat.
Without enough sleep, the brain reduces leptin and increases ghrelin, which increases our hunger. This explains why someone likes to overeat at nighttime, leading to unwanted weight gain. Proper and adequate sleep at night can also help people keep their blood sugar under control. Sleep deprivation causes the body to release less insulin after we eat. This hormone helps to reduce the blood sugar level. Thus, lack of sleep can lead to diabetes mellitus. Disruption of sleep and circadian rhythms may increase vulnerability to digestive disorders, including reflux, ulcers, inflammatory bowel issues and irritable bowel disease.
Indications of sleep deprivation could include excessive fatigue through the day, frequent yawning and irritable behaviour. Research has found that people who sleep less have a decreased ability to take in and process bits of new information and to focus attentively while performing a task, which impairs the ability to judge situations accurately and respond accordingly.
Sleep is also critical to our ability to think clearly, be vigilant and alert and sustain attention; memories are consolidated during sleep and sleep serves a key role in emotion regulation. Insufficient sleep can lead to irritability, fatigue, difficulty with concentration and memory and problems with socializing, leading to feelings of loneliness. These effects can contribute to more severe mental health disorders, such as psychosis or mania, in the long term, warns Dr Kovale.
