Women's quality sleep is significantly influenced by the balance between daily caloric intake and energy expenditure through physical activity, according to a new study. Researchers found that eating appropriately based on one's activity level helps reduce the risk of sleep deprivation more effectively than indiscriminate fasting or simply increasing exercise.
A research team led by Professor Park Min-sun of the Department of Family Medicine at Seoul National University Hospital and Professor Seo Min-jeong of the Department of Family Medicine at SMG-SNU Boramae Medical Center announced Wednesday that they analyzed the link between energy intake-expenditure balance and sleep duration in 13,164 adults who participated in the Korea National Health and Nutrition Examination Survey in 2019, 2020, and 2022.
The researchers calculated an "Energy Intake-Expenditure Balance" (EIEB) indicator by subtracting consumption based on basal metabolic rate and physical activity from daily energy intake. They then divided the subjects into four groups based on EIEB values. An EIEB value close to zero indicates a state of consuming as much as one expends; a negative value means insufficient energy intake; and a positive value means intake exceeds expenditure.
The analysis showed that among women, the second-quartile group, which had a balance between intake and expenditure, had a 29% lower risk of short sleep compared with the first-quartile group, which had the most severe energy deficit. The research team defined short sleep as sleeping six hours or less per day.
The third-quartile group, with slightly excess energy, and the fourth-quartile group, with excessive intake, also had 25% and 24% lower risks of short sleep, respectively, compared with the first-quartile group. However, the sleep improvement effect was greater in the balanced second-quartile group than in the fourth-quartile group, which had the highest energy intake.
The research team explained that this shows balance between intake and expenditure is important, rather than simply eating more leading to better sleep. Such an association was not clearly observed in men.
The team attributed the female-specific association to gender differences in "neuroendocrine-immune regulation." During sleep, the body uses about 400 kcal to activate immune cells and reduce inflammation. If energy is severely lacking at this time, the HPA axis, which is the stress axis, can be activated and interfere with quality sleep.
The research team estimates that women are more sensitive to changes in metabolic and immune hormones such as cortisol, the stress hormone, and leptin, the appetite-regulating hormone. As a result, when energy needed for nighttime recovery is insufficient, sleep can be more significantly affected in women than in men.
"This study confirmed that diets that simply involve eating less or only increasing exercise can actually harm sleep," Professor Park Min-sun said. "For women, maintaining a 'balance' by eating appropriately according to one's activity level is a key factor for quality sleep."
The findings were published in the Korean Journal of Family Medicine.
