To study the effects of different exercise intensity performed at different exercise times on lipid metabolism response during prolonged exercise. Nine young men performed endurance exercise at different exercise intensities (60% VO(2)max or Fatmax) in the morning (9 am to 10 am) or evening (5 pm to 6 pm); blood samples were collected before exercise and immediately and one and two hours after exercise completion. Expired gas was analyzed from the start of exercise until two hours after exercise completion. There were no significant changes in catecholamine (adrenaline and noradrenaline) and free fatty acid levels between morning and evening trials for each endurance exercise intensity. However, the morning and evening trials both exhibited significantly higher lipid oxidation at Fatmax than that at 60% VO(2)max. These results suggest that exercise at Fatmax offers greater lipid oxidation than that at 60% VO(2)max, regardless of exercise timing.