Male Marathon Runners Research Articles

Skeletal mass and body composition in marathon runners

Skeletal and lean body mass was measured in 30 male marathon runners and in 16 subjects of comparable ages who were relatively sedentary. Skeletal mass was measured by total body neutron activation analysis (total body calcium—TBCa) and photon absorptiometry of the distal radius (bone mineral content—BMC). Lean body mass was estimated by the measurement of 40K in a whole body counter (total body K—TBK). The marathon runners were slightly taller and lighter than the contrast group; the bone width of the radius was essentially the same for both groups. When the values for TBK and TBCa were corrected for age and body size, the marathon runners were found to have values that were 7% ( p < .002) and 11% ( p < .001) higher, respectively. The values of BMC were somewhat elevated in the marathon runners but this increase in regional bone mass was not statistically significant. These data suggest that marathon running may be associated with prevention of the changes that occur in body composition with aging and raise the possibility that exercise may prevent the involutional loss of skeletal and lean body mass.

Blood biochemical alterations during recovery from competitive marathon running.

The occurrence of possible prolonged alterations in plasma levels of cortisol, epinephrine, norepinephrine, selected energy metabolites, and water and electrolyte balance was assessed in six highly trained male marathon runners by measuring blood biochemical constituents on the 10th day before and for the three days following the running of a marathon. Post-race changes in hemoglobin, hematocrit, and protein levels indicated that a hemodilution had occurred, possibly as a result of elevated sodium levels. Epinephrine remained elevated until the second day. Cortisol was depressed on the first and third post-race days while variable levels were observed on the second day. No prolonged alterations were noted in norepinephrine, FFA, glycerol, triglycerides, glucose, lactate, and pyruvate.

Acute blood biochemical alterations in response to marathon running.

Adrenal-sympathico function, blood carbohydrates and lipids, and water and electrolyte balance were studied in six highly trained male marathon runners prior to and after running a marathon (26.2 miles; 42.2 km) and on control days corresponding to the above times. Fluid intake was not sufficient to maintain body weight, the runners losing approximately 2.8 kg. Estimated plasma volume losses (161 ml, 4.4%) indicated that most of the fluid loss was extravascular. Tre rose an average 2.4 degrees C and a significant negative correlation between running time and rise in Tre was observed. Glucose, fatty acids, glycerol, hemoglobin, and plasma proteins were significantly elevated after the race. Small but statistically significant increments in lactate and pyruvate were also observed. Alterations in adrenal-sympathico function were indicated by increased levels of cortisol, epinephrine, and norepinephrine.