Effect of exercise on the development of salt-induced hypertension in Dahl-S rats

Male Dahl-S rats were randomly assigned to either normal chow (NC) or high-salt (HS) diets to induce hypertension. Animals were further subdivided into trained (NCT, HST) and untrained (NCN, HSN) groups. Trained groups were exercised on a rodent treadmill 5 days per week for 12 weeks at a constant workload of 26.4 m/min, 5% grade, while duration progressed from 7.5 to 115 min/day. Arterial blood pressure was measured under anaesthesia by direct catheterization of femoral arteries after 4 and 8 weeks, and terminally via the carotid artery. Training resulted in significantly lower systolic and diastolic blood pressure in trained groups compared with untrained. The trained animals also had significantly lower body weights. Analysis of regressed organ weights adjusted for differences in final body weight revealed that the NCT animals had heavier hearts and kidneys than the NCN animals. The HST animals had heavier hearts and lighter kidneys than the HSN animals.