Five healthy middle-aged men were asked to perform 18 holes of golf. Heart rate was measured throughout the play, and blood samples were compared before and after play. Oxygen uptake during play was estimated from their heart rate response during a treadmill-walking test. Mean heart rate was 108 (range 92-121) beats/min, which corresponded to 38 (range 35-41) %VO2max. Caloric cost of golf is 4-6 kcal/min and total energy expenditure was estimated more than 960 kcal during 18 holes. Blood glucose decreased and FFA increased following 18 holes of play. Golfing seems to be a suitable sport for middle-aged and elderly persons to enhance energy expenditure.