High-intensity exercise (HI), is known potentially to reduce cardiometabolic risk. However, HI is a constraint to older adults. The burdens of HI in older age can be achieved by high- intensity interval training (HIIT) which is considered to be useful. Although HIIT is considered as beneficial, its safety and feasibility in older adults should be carefully assessed. We studied the skeletal muscle response to HIIT in older adult rats. Fifteen male Wistar rats (12 months) were divided into 3 groups: HIIT group; control 1 (C1, 12 months); control 2 (C2, 14 months as sedentary control group. Parameters use are blood lactate; skeletal muscle's Troponin-T (TnT) and PGC-1α. Treatment consisted of 4 minutes of high intensity active running on a treadmill with 1 minute interval; 4X of repetition for 8 weeks. After treatment rats were sacrificed, blood and gastrocnemius muscles were collected. Results showed that blood lactate in HIIT was insignificantly higher compared to C2 and was significantly higher in C2 compared to C1 (p=0.032). PGC-1α in HIIT was significantly higher compared to C2 (p=0.024) and significantly lower in C2 compare to C1 (p=0.022). TnT of HIIT was significantly higher compared to C2 (p=0.002). Our results indicated that response of skeletal muscle tissue to HIIT for 8 weeks provided benefited and was feasible for older adults. © Universiti Putra Malaysia Press.