Abstract
ALAHMADI, M. A., A. P. HILLS, N. A. KING, and N. M. BYRNE. Exercise Intensity Influences Nonexercise Activity Thermogenesis in Overweight and Obese Adults. Med. Sci. Sports Exerc., Vol. 43, No. 4, pp. 624-631, 2011. Purpose: The purpose of this study was to determine the effect of acute bouts of moderate-and high-intensity walking exercise on nonexercise activity thermogenesis (NEAT) in overweight and obese adults. Methods: Sixteen participants performed a single bout of either moderate-intensity walking exercise (MIE) or high-intensity walking exercise (HIE) on two separate occasions. The MIE consisted of walking for 60 min on a motorized treadmill at 6 km.h(-1). The 60-min HIE session consisted of walking in 5-min intervals at 6 km.h(-1) and 10% grade followed by 5 min at 0% grade. NEAT was assessed by accelerometer 3 d before, on the day of, and 3 d after the exercise sessions. Results: There was no significant difference in NEAT vector magnitude (counts per minute) between the preexercise period (days 1-3) and the exercise day (day 4) for either the MIE or the HIE protocol. In addition, there was no change in NEAT during the 3 d after the MIE session; however, NEAT increased by 16% on day 7 (postexercise) compared with the exercise day (P = 0.32). However, during the postexercise period after the HIE session, NEAT was increased by 25% on day 7 compared with the exercise day (P = 0.08) and by 30%-33% compared with the preexercise period (days 1, 2, and 3; P = 0.03, 0.03, and 0.02, respectively). Conclusion: A single bout of either MIE or HIE did not alter NEAT on the exercise day or on the first 2 d after the exercise session. However, monitoring NEAT on a third day allowed the detection of a 48-h delay in increased NEAT after performing HIE. A longer-term intervention is needed to determine the effect of accumulated exercise sessions over a week on NEAT.