Role of four-week resistance exercise in preserving the heart against ischaemia-reperfusion-induced injury.

OBJECTIVE: We studied the cardioprotective effect of resistance training against ischaemia-reperfusion-induced injury. METHODS: Forty male rats were divided into trained and sedentary groups (n = 20 for each). The trained rats were exercised at 12 repetitions/set, four sets/day and five days/week for four weeks. Transient regional ischaemia of the left anterior descending coronary artery (40 min) was followed by 80 min of reperfusion. RESULTS: Baseline developed and diastolic pressures and coronary flow were similar in the two groups. While diastolic pressure increased and developed pressure and coronary flow decreased in both the ischaemic and perfusion periods (as indices of cardiac damage), there were no statistically significant differences between the trained and sedentary groups in these parameters. Resistance training did not significantly change the infarct size and apoptosis rate. CONCLUSION: We did not see a cardioprotective effect of resistance exercise against ischaemia-reperfusion-induced injury in this study. A precise conclusion about this issue needs more investigations.

Role of 12-week resistance training in preserving the heart against ischemia-reperfusion-induced injury.

BACKGROUND: Discovering an effective approach to provide cardioprotection against coronary artery disease has long been sought. We studied the cardioprotective effect of resistance training against ischemia-reperfusion-induced injury. METHODS: Twenty male rats were divided into trained and sedentary groups (n = 10 in each). The rats were exercised in squat-training apparatus (12 repetitions/set, four sets/day and five days/week for 12 weeks). After the last training session, transient regional ischemia of left anterior descending coronary artery (40 min) was followed by 80 min of reperfusion. Coronary flow, left ventricular developed pressure, diastolic pressure and infarct size were measured. RESULTS: After 35 min of ischemia, coronary flow and developed pressure were higher in trained than untrained groups (10.37 ± 0.96 vs 7.54 ± 0.89 mL/min × g, p < 0.01 for coronary flow and 67.74 ± 3.31 vs 52.39 ± 4.28 mm Hg, p < 0.01 for developed pressure) and this difference persisted until 50 min of reperfusion (10.59 ± 0.88 vs 7.71 ± 0.73 mL/ /min × g, p < 0.01 for coronary flow and 58.12 ± 4.07 vs 39.56 ± 3.79 mm Hg, p < 0.01 for developed pressure). Diastolic pressure was significantly lower from 35 min of ischemia (11.51 ± 5.37 vs 24.53 ± 5.44 mm Hg, p < 0.05) through 35 min of reperfusion in trained rather than sedentary rats (30.62 ± 3.19 vs 43 ± 7.11 mm Hg, p < 0.01). Resistance exercise training reduced the infarct size statistically in trained rats as compared with sedentary animals (39.32 ± 4.09 vs 29.36 ± 4.17 percentage of zone at risk, p < 0.05). CONCLUSIONS: These results show that chronic resistance exercise provides cardioprotection against myocardial injuries.