[Purpose] The purpose of this study was to determine the standard alterations in normal adult physiological states and gait parameters resulting from changes in treadmill slope during the use of the treadmill as a medical reference. [Subjects] The subjects of this study were 12 normal, healthy volunteers without any orthopedic, respiratory or cardiovascular system problems. [Methods] The gait of subjects was measured using Optogait on an inclined treadmill for 3 minutes. Gait was measured at slopes of 0%, 9% and 18%. The subjects wore a Pansystolic murmur (PSM) training device over their xiphoid process in order to measure physiological changes. The speed of the treadmill was fixed at 5.0 km/h in order to maintain a constant walking speed. [Results] The subjects’ gait parameters were observed to change significantly between slopes of 0% and 18% and the physiological states which showed significant changes were average heart rate, recovery heart rate, average respiratory rate, and angular displacement of the trunk. [Conclusion] The results of this study may be used as a medical reference for gait training on a treadmill, especially for treadmills with adjustable gradients.