People with insomnia tend to experience poorer sleep quality when their basal metabolic rate (BMR) is low, according to a new study. Researchers suggest that when energy expenditure for basic life functions drops to a "power-saving mode," maintaining sleep stability becomes more difficult.
Professor Bae Hee-won from the Department of Neurology at Inje University Ilsan Paik Hospital and the sleep research team from Samsung Seoul Hospital's Department of Neurology analyzed how BMR levels affect sleep quality depending on the presence of insomnia. The findings were published in Sleep Medicine Research, a journal issued by the Korean Society of Sleep Medicine, the researchers announced Sunday.
The team compared and analyzed 450 adults who underwent polysomnography, dividing them into insomnia and non-insomnia groups.
BMR refers to the minimum energy expenditure required for vital functions such as breathing, heartbeat, and body temperature regulation, even without any physical activity. BMR decreases when caloric intake is drastically reduced or when muscle mass declines due to injury, illness, or reduced physical activity.
The study found that the difference in average daily BMR between the insomnia group (1,409 kcal) and non-insomnia group (1,426 kcal) was minimal. However, among insomnia patients, sleep health varied significantly based on BMR levels. Those with lower BMR had shorter total sleep time and more frequent awakenings during sleep, while insomnia patients with higher BMR showed relatively better total sleep time and sleep efficiency, with reduced time to fall asleep and less time awake during sleep. No clear correlation between BMR and sleep indicators was found in the non-insomnia group.
The researchers explained that rather than directly determining the onset of insomnia, BMR may act as a factor affecting sleep stability in those who already have sleep disorders.
Insomnia is associated with physiological characteristics that keep the body in an alert state, including increased sympathetic nervous system activity and elevated stress hormones. When BMR is also low in this state, the body may struggle to maintain energy balance during sleep, making sustained stable sleep even more difficult, the researchers noted.
"BMR is not a diagnostic indicator for insomnia, but it can be a physiological factor that explains sleep quality," Professor Bae said. "Maintaining an appropriate metabolic state through regular exercise and a balanced diet can also benefit sleep health."
