TRAINING EFFECTS OF SHORT AND LONG BOUTS OF BRISK WALKING IN SEDENTARY WOMEN

This study compared the effects of short and long bouts of brisk walki ng in sedentary women. Forty seven women aged 44.4 +/- 6.2 yr (mean +/ - SD) were randomly assigned to either three 10-min walks per day (sho rt bouts), one 30-min walk per day (long bouts) or no training (contro l). Brisk walking was done on 5 d.wk(-1), at 70 to 80% of maximal hear t rate, typically at speeds between 1.6 and 1.8 m.s(-1) (3.5 and 4.0 m ph), for 10 wk. Subjects agreed not to make changes to their diet. Twe lve short-bout walkers, 12 long-bout walkers, and 10 controls complete d the study. Relative to controls, (V)over dot O-2max (short-bout, +2. 3 +/- 0.1 mL.kg(-1).min(-1); long-bout, +2.4 +/- 0.1 mL.kg(-1).min(-1) ; controls, -0.5 +/- 0.1 mL.kg(-1).min(-1)) and the (V)over dot O-2 at a blood lactate concentration of 2 mmol.L-1 increased in walkers (bot h P < 0.05), with no difference in response between walking groups. Ne ither heart rate during standard, submaximal exercise nor resting syst olic blood pressure changed in a different way in walkers and controls . The sum of four skinfold thicknesses decreased in both walking group s (P < 0.05) but body mass (short-bout, -1.7 +/- 1.7 kg; long-bout, -0 .9 +/- 2.0 kg; controls, +0.6 +/- 0.7 kg) and waist circumference decr eased significantly only in short-bout walkers. Changes in anthropomet ric variables did nor differ between short- and long-bout walkers. Thu s short bouts of brisk walking resulted in similar improvements in fit ness and were at least as effective in decreasing body fatness as long bouts of the same total duration.