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

Purpose: 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). Methods: 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. Results: 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) (0) (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, % HRpeak, and kcal O-2 per minute at given relative efforts (% (V)over dotO(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 (% METpeak) was greater for the O group (61.5+/-2.5 vs 48.8+/-2.2) (P<0.05). Conclusions: 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.