ABSTRACT

　It is important to maintain the skeletal muscle mass for extending healthy lifeexpectancy. Recently, myokine which is released from skeletal muscle by musclecontraction has been paid attention for maintain of muscle mass. Many studiessuggested that the myokoines are facilitated by high-volume exercise. The purpose ofthe present study was to verify that myokines, involved in maintain of muscle mass, areenhanced by low-intensity exercise under cold environment.　Six healthy males （Age: 22.4 ± 0.4 yrs, height: 171±2.7 cm, weight: 63.8±2.8kg） conducted exercise with a normal temperature condition （n = 6） and exercisewith a cold temperature condition（ n = 6）．All subjects performed pedaling at 60% ofmaximal oxygen uptake （V･O2max） for 60 min in each condition. Blood samples werecollected before exercise, during exercise, immediately after exercise, and 1, 3, and 24 hafter exercise.　Unanticipatedly, Irisin and FGF21 concentrations in blood did not show significantdifference between groups. However, decreased blood insulin concentration wasimpaired in cold temperature condition, but not normal temperature condition. Therefore, these results suggested that exercise with cold environment did not effectivefor myokines, involved in maintain muscle mass response to exercise.

DECENTE SPORTS SCIENCE Vol.40/The DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE