Cardiorespiratory fitness in groups with different physical activity levels

The aim of the study was to determine how different categorizations of self-reported and objectively measured physical activity (PA) reflect variations in cardiorespiratory fitness (VO2max). A total of 759 individuals (366 women) with a mean age of 48.5 years (SD 14.4) wore an accelerometer (ActiGraph GT1M) for seven consecutive days and answered the short International Physical Activity Questionnaire (IPAQ). VO2max was directly measured during a continuous graded exercise treadmill test until exhaustion. Men and women categorized as highly active by IPAQ had 9% and 13% higher VO2max, respectively, than those reporting a low PA level (P<0.05). Men and women meeting the PA recommendation of 150min/week of daily moderate intensity PA, measured by accelerometer, had 13% and 9% higher VO2max, respectively, than participants not meeting this recommendation (P<0.01). No significant differences in average sedentary time, analyzed in total min/day and in bouts of 10 and 30min, were found between participants with high or low cardiorespiratory fitness. However, women spent less time than men in bouts of sedentary behaviors. Self-reported PA by IPAQ and objectively measured PA by accelerometer were both useful instruments for detecting differences in VO2max.