Subcutaneous Glucose Concentration as a Predictor Variable for Energy Expenditure during Resistance Exercise in Humans

The paper describes concurrent, minute-by-minute dynamics of subcutaneous glucose concentration and energy expenditure in young male subjects performing 40-min resistance exercise in a whole room calorimeter. The observed negative correlation between subcutaneous glucose concentration, as measured by continuous glucose monitoring (CGM) sensor and energy expenditure is exploited to propose and validate a simple linear model, which is used to estimate minute-by-minute energy expenditure from CGM sensor readings. The data were collected from seven young adult male subjects during their 48-hour stay in calorimeter room. Each subject had two 48-hour calorimeter sessions, except one subject who only performed one session. The minute-by-minute CGM data were regressed on energy expenditure (EE) data thus obtaining a linear model connecting these two quantities. This model was subsequently used to estimate EE from CGM readings for the data that were not used in the training dataset. The performance of the linear regression models was analyzed using Bland-Altman plots and it is demonstrated that the CGM sensor can provide a valid predictor variable which can be combined with other physiological parameters to estimate energy expenditure in field conditions.