Measuring Muscle Post-Exercise Oxygen Consumption in Individuals with a Family History of Diabetes

Background: Post-exercise oxygen consumption (EPOC) contributes to the health benefits of exercise, and changes in EPOC may play a role in the development of diabetes. Near-infrared spectroscopy (NIRS) is a tool used to evaluate muscle metabolism. This study used a novel NIRS-based method of measuring EPOC in the forearm muscles of young adults with and without a family history of diabetes. Methods: Fourteen female adults with and without an immediate family history of diabetes were tested. A two-group, one-day design was used with three protocols: ischemic reperfusion, EPOC, and mitochondrial capacity. Muscle oxygen levels were measured with NIRS in the forearm. Blood flow was assessed as the initial reperfusion rate following 5 min of ischemia. EPOC was measured after 60 s of rapid wrist curls with a 2.3 kg weight, followed by measurements every minute for 10 min. Muscle mitochondrial capacity (mVO₂max) was determined from the recovery rate of muscle metabolism after 30 s of electrical stimulation. EPOC was calculated as the area under the curve of oxygen consumption over 10 min after exercise, subtracting the phosphocreatine contribution calculated from mVO₂max. Group comparisons were made using t-tests with significance at p < 0.05. Results: mVO₂max was not different between those with a positive (1.60 ± 0.15 min^-1) and those with a negative family history (1.45 ± 0.17 min^-1), p = 0.11. Net EPOC was not different between those with a positive (20.0 ± 7.2 O₂·s) and those with a negative (19.6 ± 11.3 O₂·s) family history, p = 0.94. Conclusions: Muscle EPOC minus PCr was calculated after a short, intense bout of exercise. No differences were found in the mitochondrial capacity or EPOC between young healthy individuals with and without a family history of diabetes. This study presents the use of EPOC to evaluate muscle metabolism in populations at risk for diabetes and other related disorders.