Cardiopulmonary fitness as measured by maximal oxygen uptake (VO2max) is routinely estimated from submaximal heart rate (HRsubmax). Propranolol reduces HRsubmax and invalidates regression estimates of VO2max. The present study examines the influence of four additional antihypertensive medications on VO2 max prediction by measuring VO2 and HR during exercise testing of 20 normotensive men aged 20 to 30 years. Five medications were assigned by double-blind randomization: (1) hydrochlorothiazide (H) 50 mg/day; (2) II + methyldopa 10 mg/kg/day (H + M); (3) chlorthalidone 50 mg/day + reserpine 0.1 mg/day (C + R); (4) 11 (50 mg) + reserpine (0.125 mg) one/day + hydralazine 0.50 mg/kg/day (C + R + HY), and (5) placebo (P). Each participant exercised before being given medication, ivhile receiving medication, and after medication washout. No antihypertensive drug was associated with significant decrease in P-adjusted resting blood pressure, but H + M and C + R were associated with significantly decreased exercise systolic blood pressure adjusted for P. Multiple t tests did not show a significant effect on the HR-VO2 relationship for any drug adjusted for P. We conclude that short-term administration of these antihypertensive drugs does not confound HRsubmax-estimated VO2max.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Cardiac Rehabilitation|
|State||Published - Feb 20 1984|