RESPONSES OF PEOPLE WITH CORONARY-ARTERY DISEASE TO COMMON LAWN-CARE TASKS

The primary purpose of the present study was to determine oxygen uptak e (V over dot O-2) and heart rate (HR) responses of patients with coro nary artery disease (CAD) to common lawn-care activities. The study wa s conducted in three phases. In phase I, 8 men with CAD performed 30 m in of push motorized lawn mowing at a self-paced rate. In phase II, 9 men with CAD performed push (no power) mowing, trimming (power and man ual), and raking for 8 min each. In phase III, age-matched men and wom en with and without CAD (9-11 per group) performed self-propelled moto rized mowing and push motorized mowing. In phase I, V over dot O-2 ave raged 17.3 (SEM 3.8) ml . kg(-1). min(-1) during 30 min of mowing. Rel ative effort was 68 (SEM 1) and 76 (SEM 4)% of treadmill maximal V ove r dot O-2 (V over dot O-2max) and HR, respectively. In phase II, mean V over dot O-2 ranged from 8.6 (SEM 0.4) with grass trimming to 22.2 ( SEM 1.6) ml . kg(-1). min(-1) with push manual mowing. With self-prope lled mowing at three speeds in phase III, mean 30, of the CAD groups r anged from 9.5 (SEM 0.3) to 13.8 (SEM 1.4) ml . kg(-1). min(-1) and re presented 37%-62% V over dot O-2max. The results indicated that lawn m owing is often performed at an exercise intensity recommended for aero bic exercise training; patients who achieve a treadmill peak capacity of 4 times resting metabolic rate (4 METs) should be able to perform s elf-propelled motorized lawn mowing (slow speed) and grass trimming at less than 80% peak V over dot O-2; and V over dot O-2 demands of lawn mowing can be adjusted by equipment selection and/or pace.