Metabolic and cardiovascular responses in older women during shallow-water exercise

The purpose of this investigation was to examine the metabolic and cardiovascular demands of shallow-water exercise in older women. Sixteen active older women who were not taking cardiac medication participated in this investigation (mean +/- SE; age, 66.4 +/- 1.2 years). Testing included (a) resting metabolic rate and heart rate; (b) performing 5 8-minute, evenly paced, self-selected, submaximal, shallow-water exercise bouts. Expired air was collected during the final 3 minutes of each bout while the heart rate was recorded with a Polar heart rate monitor; and (c) a 40-minute water exercise class in which heart rate was monitored. One metabolic equivalent (MET) equaled 2.7 +/- 0.1 mlO2 x min(-1) x kg(-1), whereas resting heart rate was 63.4 +/- 2.2 b min(-1). Average submaximal MET and heart rate responses for exercise bouts 1-5 ranged from 2.8 +/- 0.1 to 5.8 +/- 0.3 and 89.7 +/- 3.0 to 119.5 +/- 3.3 b x min(-1), respectively. The rate of perceived exertion (RPE; Borg scale) response for bouts 1-5 ranged from 8.0 +/- 0.3 to 12.5 +/- 0.4. A linear relationship between MET vs. heart rate was found for each participant, with all r values greater than 0.97 (p < 0.05). The estimated MET and measured HR responses for the 40-minute water exercise class were as follows: warm-up, 4.0 +/- 0.3 and 99.5 +/- 3.4; body of workout, 5.2 +/- 0.4 and 110.0 +/- 3.8 (part 1), and 5.4 +/- 0.4 and 112.3 +/- 3.6 (part 2); cooldown, 3.6 +/- 0.3 and 95.5 +/- 3.0. The exercise intensity ranged from approximately 40-61% of the predicted maximum MET, and approximately 66-78% of the predicted heart rate maximum. Shallow-water exercise elicits metabolic and cardiovascular responses in older women that meet the American College of Sports Medicine exercise prescription guidelines for realizing health benefits.