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Biomedical subjects

D R Bransford

Publications and source records attributed to D R Bransford.

3 recordsLinked to original sources

Plasma volume changes during rest and exercise in different postures in a hot humid environment.

Plasma volume shifts were investigated in five male subjects who rested and exercised in the upright, low-sit, and supine postures in a hot humid environment (49.5 degrees C, 28.9 Torr). The resting and exercise periods were each 45 min in duration. Weight losses during rest were 0.3% with an additional weight loss of 1.1% during exercise. During exercise subjects worked at either 360 or 540 kpm.min-1 in each of three postures. Each experiment was preceded by a 30-min control period in the supine posture at an ambient temperature of 22 degrees C. At rest plasma volume was reduced 17.3% in the upright, 9.0% in the low-sit, and 2.2% in the supine postures (using the end of the supine rest as the zero reference point). Supine exercise resulted in a plasma volume decrease of 11%, the low-sit 7.1%, and the upright 2.7%. The total reduction in plasma volume during the rest and exercise period was 20% in the upright, 16.1% in the low-sit, and 13.3% in the supine. No significant differences in plasma volume shifts were observed between the high and low work loads. The results indicate that the plasma volume shifts observed during rest and exercise in the heat are qualitatively similar to those observed in a cool environment.

Adult

Oxygen cost of running in trained and untrained men and women.

The purpose of this study was to compare the oxygen cost of running as it relates to speed of running among the following four groups: trained male distance runners, trained female distance runners, untrained but active men and women. Each subject was given a series of treadmill tests during which Vo2 was measured at submaximal work loads. The linear regression equation was utilized to compute the relationship between Vo2 and running speed for each groups. The results indicated that the rate of increase in Vo2 for a given increase in running speed could be represented as a straight line and was the same for all groups (P greater than .05). The trained male runners had a significantly lower Vo2 (P less than .05) than those of the other three groups at any measured speed. The trained females and untrained males had significantly lower Vo2s than the untrained females (P less than .05) at any of the given range of speeds. No significant differences were observed between the untrained mean and trained women (P greater than .05). It was concluded that there were differences in the oxygen cost of running not only between the trained and untrained groups but also between males and females.

Adult