Background: Obesity has been related to a decrease in fat oxidation. The metabolisms of fat and other substrates are increased during exercise and continue even after the exercise session. Ambient temperature possibly affects substrate oxidations during post exercise recovery.

Objective: To investigate the rates of fat and carbohydrate oxidation during post exercise recovery in the thermo-neutral versus hot environments.

Materials and Methods: Twenty-four obese female participants (age 26.9±3.9 years, BMI 36.5±7.3 kg/m²) underwent two different experimental conditions in separate visits, 5 to 7 days apart. The participants performed two sessions of 30 minutes moderate intensity (at 45% to 50% of heart rate reserve) treadmill exercise in a thermo-neutral condition (24℃ to 25℃) followed by two different conditions of 1-hour recovery period. The recovery period was randomized, either a hot (31℃ to 32℃) or thermo-neutral condition in the first visit, then the other condition in the second visit or vice versa. Substrate oxidations were determined by indirect calorimetry during the recovery period.

Results: There was no difference in the total energy expenditure between the hot (81.0±16.5 kcal/hour) and the thermo-neutral (87.0±21.3 kcal/hour) conditions (p=0.29). When compared to the hot condition, total fat oxidation during recovery in the thermo-neutral condition was significantly higher (5,716.25±2,358.42 mg/hour versus 4,288.18±1,415.22 mg/hour, p<0.001); while carbohydrate oxidation was significantly lower (8,793.71±4,049.77 mg/hour versus 10,420.84±3,040.17 mg/hour, p<0.05).

Conclusion: After exercise, recovery in a thermo-neutral environment results in a higher rate of fat oxidation. Thermo-neutral condition during the recovery period appears to be more beneficial than a hot condition in promoting fat oxidation in obese women.

Keywords: Moderate intensity exercise, Exercise recovery, Environmental temperature, Fat and carbohydrate oxidation, Obesity

Received 19 Jul 2019 | Revised 18 Nov 2019 | Accepted 22 Nov 2019