Alterations in skeletal muscle morphology in glucose-tolerant elderly hypertensive men: relationship to development of hypertension and heart rate

OBJECTIVETo compare the muscle morphology in hypertensive subjects with that in controls and to test the hypothesis of a relation between heart rate, development of hypertension and muscle morphology that is independent of glucose intolerance. PATIENTS AND METHODSWe studied 43 glucose-tolerant, untreated hypertensive subjects and 113 healthy controls in a longitudinal cohort of 70-year-old men. Metabolic status (oral glucose tolerance test and euglycemic, hyperinsulinaemic clamp test), muscle fibre distribution (myosin ATPase staining) and capillary supply (amylase-PAS method) were evaluated. Blood pressure and heart rate data were available from both ages 50 and 70 years. RESULTSHypertensive subjects had a significantly smaller mean number of capillaries per fibre than controls (1.53 versus 1.64; P = 0.04). In hypertensive subjects, the proportions of type I and type II fibres were correlated to mean arterial pressure (r = −0.56 and r = 0.52, respectively, P