Blood obtaining procedures were modified from Mundermann et al. [3]. Participants were asked to limit their physical activity 48 hours prior to the experiment. On the day of the experiment, participants made their breakfast within one hour after waking up and the experiment started two to three hours after breakfast. In addition, participants were seated on a chair for 15-min immediately before the experiment. Five-milliliter blood samples were obtained by a certified research nurse from the same antecubital vein immediately before, immediately after, and 0.5 hours after a 30-min walking exercise. During the walking exercise of the test protocol, participants walked at a pace of 5 km/h on a treadmill with 1.5 % incline. After the walking exercise, participants sat on an office chair for 30-min and were asked to rest.