Freely-Paced Walking In Healthy Adults Does Not Meet Minimum Intensity Guidelines For Health Improvement

Walking is a very popular form of physical activity and a brisk walking pace is often advised as a form of exercise. However, in order for exercise to enhance fitness it should be of sufficient intensity to elicit at least 50% of maximal oxygen consumption (VO2max) and it is not known if a brisk walk in healthy adults elicits this 50% of VO2max. Therefore, the purpose of this study was to determine if healthy adults achieve 50% of VO2max when instructed to engage in a brisk walk and to determine if a difference in intensity exists when walking on a treadmill (TM) or in a non-treadmill (NT) setting. Fourty healthy subjects (20 males and 20 females), aged 19 to 45 years, were recruited to participate in this study. Subjects underwent body composition assessment and measurement of VO2max to determine the corresponding heart rate at 50% of VO2max. Subjects then completed two 20-minute sessions of brisk walking on either a treadmill or in a non-treadmill setting with heart rate measurement used to assess exercise intensity. As determined during the measurement of VO2max, subjects were required to exercise at a heart rate of 131.7 ± 8.4 beats.min-1 in order to attain 50% of VO2max. However, the heart rates were significantly (p < 0.05) below that required to attain 50% of VO2max during TM (107.2 ± 17.5 beats.min-1) and NT (105.6 ± 17.1 beats.min-1). No differences were found between TM versus NT and males versus females. However, males took significantly (p < 0.05) fewer steps than females during TM (2484 steps ± 527 versus 2789 steps ± 428, respectively) and NT (2435 steps ± 471 vs. 2789 steps ± 353, respectively). The present data indicates that healthy adults do not walk at sufficient intensity to enhance fitness during a 20-minute brisk walk. Since most adults attain approximately 5000 steps per day and it is suggested that individuals take at least 10000 steps a day in order to promote health, it appears that adults need at least 38 minutes of walking to achieve 10000 steps per day at the recommended walking pace of the present investigation. Keywords: Aerobic fitness, heart rate, maximal oxygen consumption (VO2max), step counter. African Journal for Physical, Health Education, Recreation and Dance Vol. 14 (2) 2008: pp. 178-18