Abstract
This study was conducted (a) to determine through factor analysis techniques the basic factors underlying selected blood variables, metabolic variables, and previously determined physical and athletic fitness variables at four fixed stages of metabolic stress and (b) to determine with the t-test and through discriminant function techniques those blood variables which can discriminate between high and low levels of physical fitness. The objective of the analyses was the interpretation of the revealed information in light of previously found knowledge on the relationship of physical activity and susceptibility to heart disease. Four factors were extracted and interpreted: the effect of weight on motor fitness, the detrimental effect of aging on physical fitness, metabolic readiness, and fitness and NEFA mobility. The t-test showed statistical significance for the difference between the physically fit and unfit group means in resting serum cholesterol, submaximal exercise serum cholesterol, maximal exercise blood pH, and recovery period blood pH. The discriminant function of the combined resting and submaximal exercise serum cholesterol has a statistically determined discriminating power for the physically fit and unfit groups.