The participants were instructed to wear the PA monitor 24 hours a day. Bouts of PA were identified from minute-by-minute data and calculated as mean daily duration (min) at four different intensity levels of PA. Since individuals differing in fitness respond in markedly different ways to habitual PA at a fixed absolute intensity, we calculated the individual relative intensities of PA as MET values by adjusting to VO2R according to Howley (2001). Finally, the individual PA values at different intensities were determined at light (15–35% of VO2R), moderate (435–55% of VO2R), high (455–75% of VO2R) and very high (475% of VO2R) intensity habitual PA. If the participants’ habitual PA contained cycling, they were instructed to wear the HR monitor and record the exact time. We estimated the average MET value based on the heart rate (HR) value (Howley, 2001) and added it to the final calculation of PA. Days when daily wearing time was 5660 min were excluded. The mean percentage of excluded days for 20 participants was 59%.