Purpose: Age-related exercising leg blood flow (LBF) responses during dynamic knee-extension exercise and forearm blood flow responses during handgrip exercise are preserved in normally active men but attenuated in activity-matched women. We explored whether these age- and sex-specific effects are also apparent during isometric calf plantar-flexion incremental exercise.
Methods: Normally active young men (YM, n = 15, 24 ± 2 years), young women (YW, n = 8, 22 ± 1 years), older men (OM, n = 13, 70 ± 7 years) and older women (OW, n = 10, 64 ± 7 years) were tested. LBF was measured between contractions using venous occlusion plethysmography.
Results: Peak force obtained was higher (P < 0.05) in men compared with women and in young compared with older individuals. However, peak LBF (YM; 971 ± 328 ml min-1, OM; 985 ± 504 ml min-1, YW; 844 ± 366 ml min-1, OW; 960 ± 244 ml min-1) and peak leg vascular conductance [LVC = LBF/(MAP + hydrostatic pressure)] responses (YM; 6.0 ± 1.8 ml min-1 mmHg-1, OM; 5.5 ± 2.8 ml min-1 mmHg-1, YW; 5.3 ± 2.1 ml min-1 mmHg-1, OW; 5.5 ± 1.6 ml min-1 mmHg-1) were similar among the four groups. Furthermore, the hyperaemic (YM; 8.8 ± 3.7 ml min-1 %Fpeak-1 OM; 8.3 ± 5.4 ml min-1 %Fpeak-1, YW; 8.2 ± 3.5 ml min-1 %Fpeak-1, OW; 9.6 ± 2.2 ml min-1 %Fpeak-1) and vasodilatory responses (YM; 0.053 ± 0.020 ml min-1 mmHg-1 %Fpeak-1, OM; 0.048 ± 0.028 ml min-1 mmHg-1 %Fpeak-1, YW; 0.051 ± 0.019 ml min-1 mmHg-1 %Fpeak-1, OW; 0.055 ± 0.014 ml min-1 mmHg-1 %Fpeak-1) were not different among the four groups. These results were accompanied by similar resting LBF responses among groups and were not affected when data were normalised to estimated leg muscle mass.
Conclusions: Our results demonstrate that exercising LBF responses during isometric incremental calf muscle exercise are preserved in older men and women, suggesting that the previously observed age-related attenuations in leg and forearm hyperaemia among women may be muscle-group specific.
Keywords: Age; Blood flow; Calf exercise; Hyperaemia; Sex.