A 10mg Dose of Amiloride Increases Time to Failure During Blood-Flow-Restricted Plantar Flexion in Healthy Adults Without Influencing Blood Pressure.

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Kinesiology and Nutrition


Amiloride has been shown to inhibit acid-sensing ion channels (ASIC's), which contribute to ischemia related muscle pain during exercise. Purpose. To determine if a single oral dose of amiloride would improve exercise tolerance and attenuate blood pressure during blood-flow-restricted (BFR) exercise in healthy adults. Methods. Ten subjects (4 female) performed isometric plantar flexion exercise with BFR (30% maximal voluntary contraction) after ingesting either a 10mg dose of amiloride or a volume-matched placebo (random order). Time to failure, time-tension index (TTI) and perceived pain (visual analog scale) were compared between the amiloride and placebo trials. Mean blood pressure, heart rate, blood pressure index (BPI), and BPI normalized to TTI (BPInorm) were also compared between trials using both time matched (TM50 and TM100) and effort matched (T50 and T100) comparisons. Results. Time to failure (+69.4 ± 63.2 seconds, P<0.01) and TTI (+1,441 ± 633 Kg*sec, P=0.02) were both significantly increased in the amiloride trial compared to placebo, despite no increase in pain (+0.4 ± 1.7 cm, P=0.46). In contrast, amiloride had no significant influence on the mean blood pressure or heart rate responses, nor were there any significant differences in BPI or BPInorm between trials when matched for time (all P>0.13). When matched for effort, BPI was significantly greater in the amiloride trial (+5300 ± 1798 mmHg*sec, P=0.01), likely owing to an increase in total exercise duration. Conclusions. A 10mg oral dose of amiloride appears to significantly improve the tolerance to BFR exercise in healthy adults without influencing blood pressure responses.

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Regulatory, Integrative and Comparative Physiology

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