The Effect of Ankle Exercise on Cerebral Blood Oxygenation During and After Postural Change

Abstract

Orthostatic hypotension can cause dizziness, syncope, and falling when some individuals change their posture, due to the cardiovascular system improperly maintaining their blood pressure. The skeletal muscle pump plays an important role in adjusting hemodynamics. Ankle exercise has been proven as an effective intervention to increase venous velocity. If ankle exercise performed in a supine position is proven to have the effect of maintaining cerebral hemodynamics after postural change, it could prevent the symptoms of postural hypotension. The purpose of the present study was to determine the effect of active ankle exercise (60 s and 30 s) on postural change. Participants alternately performed plantar flexion and dorsiflexion movements of the ankle joint in the supine position. After the ankle exercise, we changed the participants’ posture from supine to sitting and oxyhemoglobin levels were evaluated. Each ankle exercise was compared with the control condition. In the 60 s ankle exercise, the oxyhemoglobin level gradually increased in accordance with exercise. There was a significant interaction effect (exercise × time) for the oxyhemoglobin level in the 60 s ankle exercise. However, there were no significant differences before and after postural change in the 30 s ankle exercise. These results suggested that the duration of ankle exercise is important to attenuate the decreased cerebral oxygenation induced by postural change.