Cardiorespiratory Fitness and Physical Activity of Morbidly Obese Individuals Measured by a Body Sensor

Abstract

PURPOSE: To assess physical activity, estimate daily total caloric expenditure (TCE) and directly measure cardiorespiratory fitness of morbidly obese individuals in a freeliving environment. METHODS: Participants (n= 10; mean + BMI= 53.6 + 11.7 kg/m2) wore an armband device that continuously monitored caloric expenditure, minute-by-minute physical activity and related variables for 24 hours. Peak or symptom-limited exercise testing with ventilatory gas exchange measurements were performed on each subject. RESULTS: Mean TCE for all individuals was 2027 ± 276 kcal. On average, subjects took 3,763 ± 2223 steps per day. Accordingly, some demonstrated extremely low levels of daily physical activity. Average peak VO2 was 16.8 ± 4.7 mL/kg/min. Number of steps per day was inversely correlated with BMI. Absolute peak VO2 correlated with TCE (r=0.628, p=0.052); moreover, relative peak VO2 was directly related to the number of steps per day (r=0.591, p=0.07) (Figure). Assuming the mean of all input values, with strict maintenance of the self-reported dietary intake and a regular moderate-intensity exercise regimen of 30 minutes per day, 5 days a week, the projected weight loss over 6 months ~19% (29.5 ± 24.1 kg).FigureCONCLUSIONS: Morbidly obese individuals with higher TCE had increased cardiorespiratory fitness and daily physical activity. These findings suggest that increasing lifestyle activity, via steps per day, represents a viable option for many morbidly obese patients to enhance weight loss and augment cardiorespiratory fitness.