Submitted to: North Dakota Academy of Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/3/1998
Publication Date: N/A
Citation: Interpretive Summary: There is limited information that attempts to explain why people with different body types perform work differently. We examined this question by evaluating nutritional status, body composition and physiological responses during exercise in men. Men with linear body types (ectomorphs) were the lightest and had the least muscle mass. Those with muscular body types (mesomorphs) were the shortest. Men with round body types (endomorphs) were as tall as the ectomorphs but had more fat and more muscle. Dietary intake and blood measurements of nutritional status were normal for all body types. At maximal exercise capacity, ectomorphs were able to match the power output of endomorphs and mesomorphs but their metabolic measurements were consistent with an increased physiological demand. This finding explains that, when nutritional status is adequate, tall thin men have limitations in performing work that requires muscular strength. This study provides the first explanation of differences in physiological function among men with different body types when nutritional status is controlled. This information will be useful to public health professionals who study the interaction between diet, body composition and physiological function.
Technical Abstract: Prior to their participation in controlled metabolic studies, sixty-three men, aged 18-40 years, were studied to examine the relationship of somatotype to nutritional status and to the physiologic response to exercise. Ectomorphs (linear body type) were the lightest and had the least muscle mass; mesomorphs (muscular body type) were the shortest; and, endomorphs (round body types) were as tall as the ectomorphs but had more fat and more muscle. All blood biochemical markers of nutritional status and intake values were within the range of normal values. Ectomorphs had increased blood superoxide dimutase activity and HDL concentrations while endomorphs had the lowest as compared to mesomorphs. Ectomorphs had the highest plasma Cu and serum Mg and, when corrected for fat-free mass, endomorphs had the highest energy intake. During cycle ergometer tests, power output was similar for the three somatotypes but ectomorphs had the highest oxygen consumption, highest respiratory exchange ratio and the highest blood lactate (in contrast, endomorphs had the lowest values). These findings indicate that men with different body types attain similar peak power outputs during progressive exercise despite differences in muscle mass. The findings suggest that somatotype is associated with an altered metabolic response during progressive exhaustive exercise that is related to body cell mass.