Biol. Pharm. Bull. 29(10) 2106—2110 (2006)

ing factors. First, myoglobin and an energy metabolic system coenzyme leak out into the blood from cells and tissues damaged by exercise, and destruction of red blood cells occurs. Second, exercise promotes consumption of energy sources such as glycogen by mobilizing internal energy metabolism to the maximum and using and depleting the energy source. Third, through these processes, exercise causes the production and accumulation of products of metabolism, such as lactic acid, in the body. Therefore, recovery from exercise fatigue requires repair of the damage that has occurred in the body. Specifically, resynthesis of the leaked cell and tissue components and consumed energy sources is needed, as are decomposition and removal of accumulated byproducts of metabolism. During in vivo screening for endurance capacity and antifatigue foods, astaxanthin was found to have a potent enhancing effect on endurance capacity in mice. Astaxanthin, a red carotenoid pigment, is a biological antioxidant that occurs naturally in a wide variety of living organisms. It has many highly potent pharmacological activities, such as antioxidative activity, anti-tumor and anticancer effects, immunomodulating actions, and anti-diabetic and anti-inflammatory actions. The chronic effects of astaxanthin on endurance capacity have not previously been demonstrated. In the present study, we investigated endurance capacity by administering astaxanthin to mice and then subjecting the animals to exercise in the form of swimming.