Cardiovascular safety and effects on peripheral circulation of a leg resistance exercise training in the elderly

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Safety of leg-resistance exercise (straight leg raising (SLR) and knee extension (KE)) was examined in 175 elderly subjects and usefulness of respiratory guidance (exhale slowly and not hold one's breath during exercise) was in 31 subjects. Myocardial scintigraphy was performed in 18 patients with coronary artery disease. There were no chest symptoms during the exercise. None had ischemic ST changes during the exercise. Excessive rise in blood pressure (systolic blood pressure>180mmHg) was revealed during 60%1RM exercise intensity in about half subjects. Blood pressure elevation during exercise was significantly lowered by respiratory guidance. Leg-resistance exercise is safe for the elderly less than 75 years with less than 60%1RM exeicise intensity and appropriate respiratory guidance. Of 20 elderly subjects more than 75 years, 9(45%) had excessive blood pressure rise and 1(5%) had severe muscle pain during leg-resistance exercise. Therefore, careful exercise prescription is required … More for the elderly>75 years of age. The myocardial scintigraphy during exercise revealed reversible perfusion defects in 8(44%) of the 18 patients. Thus, leg-resistance exercise can possibly induce myocardial ischemia even though there is absence of anginal symptoms and ischemic ST-segment depression or elevation in patients with clinically stable coronary artery disease. No cardiac events occurred in 106 subjects participated in supervised resistance training program (3〜24 months).The blood-volume and oxygenation in exercising muscles during leg-resistance exercise (KE) was studied with near-infrared spectroscopy in 54 middle aged or elderly subjects. The total hemoglobin index (THI) as the index of blood volume and the oxygenation evaluated by % TOI was measured continuously during exercise. The %THI increased significantly during exercise. There was a weak but significant negative correlation between the serum total cholesterol concentration and the %THI. These results suggested that hypercholesterolemia is associated with impaired blood-volume response to leg-resistance exercise in middle-aged or elderly subjects. The % TOI significantly decreased between 40%-1RM and 60%-1RM, while did not between 60%-1RM and 80%-1RM. The thigh skin fat thickness and 1RM-weight correlated to the %TOI changes. In conclusion, the oxygenation changes in exercising muscles during leg-resistance exercise are influenced by the exercise intensity in middle-aged or elderly subjects. Less