Responses of people with coronary artery disease to common lawn-care tasks.

The primary purpose of the present study was to determine oxygen uptake (VO2) and heart rate (HR) responses of patients with coronary artery disease (CAD) to common lawn-care activities. The study was conducted in three phases. In phase I, 8 men with CAD performed 30 min 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 manual), and raking for 8 min each. In phase III, age-matched men and women with and without CAD (9-11 per group) performed self-propelled motorized mowing and push motorized mowing. In phase I, VO2 averaged 17.3 (SEM 3.8) ml.kg-1.min-1 during 30 min of mowing. Relative effort was 68 (SEM 1) and 76 (SEM 4)% of treadmill maximal VO2 (VO2max) and HR, respectively. In phase II, mean VO2 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-propelled mowing at three speeds in phase III, mean VO2 of the CAD groups ranged from 9.5 (SEM 0.3) to 13.8 (SEM 1.4) ml.kg-1.min-1 and represented 37%-62% VO2max. The results indicated that lawn mowing is often performed at an exercise intensity recommended for aerobic exercise training; patients who achieve a treadmill peak capacity of 4 times resting metabolic rate (4 METs) should be able to perform self-propelled motorized lawn mowing (slow speed) and grass trimming at less than 80% peak VO2; and VO2 demands of lawn mowing can be adjusted by equipment selection and/or pace.