Unprompted vigorous physical activity is associated with higher levels of subsequent sedentary behaviour in participants with low cardiorespiratory fitness: a cross‐sectional study

Performing physical activity is considered health promoting but may induce a need for subsequent rest periods. This study aimed to determine the within‐day interactions between vigorous physical activity (VPA) and sedentary behaviour (SB) in participants with low cardiorespiratory fitness. We tested the hypothesis that VPA is associated with a temporary subsequent increase in SB. One week of accelerometer data containing a minimum of one 10‐min bout of VPA from 62 participants with low cardiorespiratory fitness (31–50 years old) were obtained from the MILE study. A comparison of SB was made between days with a bout of VPA and days without (control). Due to a positive association between VPA and number and duration of sedentary bouts, the time accumulated in both uninterrupted and total sedentary bouts were 27 (95% CI, 10–45) min and 29 (95% CI, 9–50) min higher on VPA days compared to control days ( P < 0.05). Our results indicate that in participants with low cardiovascular fitness, unprompted VPA is positively associated with an increase in subsequent sedentary time. We propose that such VPA‐associated sedentary time may be viewed as part of a healthy activity pattern.