Metabolic and cardiovascular response to shallow water exercise in young and older women

The purpose of this study was to compare the metabolic and cardiovascular responses of young (Y) and older (O) women ages 19-24 yr (N = 11) and 63-72 yr (N = 11), respectively, while performing shallow water exercise (SWE).

Resting metabolic rate was determined as was the metabolic (indirect calorimetry) and heart rate (Polar monitor) responses to five submaximal and one maximal SWE bout, and to a 40-min SWE class.

1) One metabolic equivalent (MET) equaled (mean +/- SE) 3.3 +/- 0.2 mL O(2).min-1.kg-1 (Y) and 2.8 +/- 0.1 mL O(2).min-1.kg-1 (O) (P < 0.05); 2) submaximal (bouts 1-5) MET and HR responses ranged from 3.5 to 8.6 and 95 to 144 bpm (Y), and 3.2 to 6.3 and 92 to 124 bpm (O); 3) estimated MET, % HR(peak), and kcal O(2) per minute at given relative efforts (% [OV0312]O(2peak)) were greater for the older group (P < 0.05), whereas no difference in RPE was found; 4) peak MET and HR equaled 11.7 +/- 0.8 and 182 +/- 3 bpm (Y) and 7.6 +/- 0.4 and 156 +/- 5 bpm (O), respectively (P < 0.05); 5) SWE class: overall, estimated average MET level was 4.9 +/- 0.3 (O) and 5.8 +/- 0.4 (Y) (P > 0.05); the overall relative intensity (% MET(peak)) was greater for the O group (61.5 +/- 2.5 vs 48.8 +/- 2.2) (P < 0.05).

SWE elicited metabolic and cardiovascular responses that met ACSM's guidelines for establishing health benefits. Furthermore, older females may self-select a greater relative exercise intensity during SWE compared with younger counterparts when provided with the same verbal instructions and encouragement.