Potential Indicator for Obesity Risk Detected during Sleep

Researchers at the University of Tsukuba in Japan show that low metabolic flexibility is associated with reduced fat metabolism during sleep

Tsukuba, Japan—Throughout the day, we gain energy by breaking down carbohydrates, fats, and proteins in our bodies through the process of metabolism. The body’s ability to switch metabolic energy sources in response to changes in nutritional state, such as after meals and during sleep, is called metabolic flexibility. Research has shown that disrupted flexibility is associated with diseases such as obesity and diabetes. Professor Kumpei Tokuyama and his team of researchers at the University of Tsukuba have been studying metabolism during sleep.

The basic method used by the team centers around a measurement called the respiratory quotient, abbreviated as RQ, which measures how much oxygen we use and how much carbon dioxide we breathe out. To characterize metabolic changes over time, the researchers measured the carbon dioxide/oxygen ratios from 127 people, every 5 minutes over a 24-hour period. As a result, they found that while RQ values decreased steadily at the beginning of sleep, after reaching a low point, they began to rebound after midnight and continued to increase until people woke up.

Preventing diseases such as obesity and diabetes is much more preferable to treating them. Yearly checkups that focus on measuring sleeping RQ values could help screen for people at risk for developing metabolic diseases, thus allowing timely interventions.

Press Release