Effect of high-salt diet or chronic captopril treatment on exercise capacity in normotensive rats

1. We investigated whether chronic suppression of the renin-angiotensin system, which is known to be associated with reductions in microvascular density and vasodilator responsiveness of skeletal muscle, could affect exercise capacity in normotensive rats. 2. Rats were placed on normal rat chow, normal rat chow with captopril (100 mg/kg per day) or a high-salt diet (HS; 4%) for 4 weeks. Following these interventions, rats with indwelling carotid artery catheters were submitted to stepwise increasing exercise on a motor treadmill at a speed of 10, 20 and 30 m/min for 4 min while blood lactate was measured. 3. Blood lactate after exercise at a speed of 20 m/min was significantly higher and the duration during which rats were able to run at a speed of 30 m/min was significantly shorter in captopril-treated rats and rats fed an HS diet compared with control rats. 4. We conclude that chronic treatment with captopril or HS diet could reduce the exercise capacity in inactive normotensive rats, probably through chronic inhibition of the renin-angiotensin system.