1.1. Cardiovascular fitness and health issues

Cardiovascular training has been well documented to provide health and fitness benefits through adaptations within the central and peripheral circulatory systems. The ability to perform prolonged sub-maximal exercise (VO2max) is the only objective measure of cardiorespiratory fitness which is used in studies of cardiovascular fitness. Studies by Kaeferlein et al (1998) showed that aerobic type exercise conducted three times weekly over 20 weeks significantly improved heart rate variability and VO2max in subjects having initially lower VO2max. Heart rate variability, a parasympathetic activity indicator which is positively associated with cardiovascular fitness, is calculated as a square root of the mean square of the differences. It has also been shown to correlate positively with lactate threshold (Lima and Kiss, 1998), suggesting that heart rate response may be a reliable indicator of training intensity. Hence, heart rate response during horseback riding is monitored over different riding gaits to indicate training intensity in trained control subjects and untrained experimental subjects. The experimental group of untrained subjects would undergo an introductory course in basic riding skills in order to reduce initial feelings of anxiety that may influence heart rate response to the physical activity.