Heart Rate Response to Submaximal and Maximal Workloads During Running and Swimming

The purpose of the present study was to determine if common indexes of exercise intensity, assessed with land-based exercise, could be applied to swimming. Consequently, the heart rate (HR) and oxygen uptake (VO₂) responses to sub-maximal and maximal treadmill running (TR) and free swimming (SW) in 11 fitness swimmers were assessed to determine if the responses to TR could be used to predict those of SW. A maximal graded exercise test using a discontinuous protocol was used for TR, while four graded submaximal 200yd swims and one 400yd maximal swim was used for SW. Rest periods were similar for each mode. Significantly lower (p<0.05) peak values were found in SW compared to TR for both HR (174 ± 3 vs 183 ± 3 bt × min^-1) and VO₂ (3.58 ± 0.18 vs 3.97 ± 0.22 L x min^-1), SW vs TR; ±SE, respectively. However, regression analyses of submaximal HR vs VO₂ for each subject revealed similar slopes for TR and SW (30.5 ± 1.7 vs 29.9 ± 3.5 bt × l^-1, p > 0.05) and similar intercepts (67.3 + 2.6 vs 66.5 + 11.5 bt × min^-1, p > 0.O5). At the VO₂ equivalent to 50 % treadmill VO₂max, the heart rate predicted from SW did not differ significantly from TR (118 ± 5 vs 124 ± 1 bt × min^-1 p > 0.05). This was also true at 85 % treadmill VO₂max (171 ± 4 vs 166 ± 3 bt × min^-1, SW vs TR, respectively; p >0.05). These data suggest that peak heart rate and oxygen uptake appear to be mode specific, but exercising at a given submaximal oxygen uptake will elicit a similar heart rate regardless of the mode. Thus, target heart rate ranges designed for land-based exercise appear to be appropriate for fitness swimmers during swimming.

Key words

Oxygen uptake - heart rate - treadmill running - free swimming - exercise intensity prescription