Before revision: The basic physiological change that occurs in the body during prolonged standing or sudden stand from supine position is that there will be increased pooling of blood in leg, which decreases the venous return avd so there will be decreased cardiac output, which ultimately causes systolic Blood pressure to fall (hypotension).
After revision: The basic physiological change that occurs in the body during prolonged standing or sudden stand from supine position is that there will be increased pooling of blood in leg, which decreases the venous return and so there will be decreased cardiac output, which ultimately causes systolic Blood pressure to fall (hypotension).