ISSN:
1439-6327
Keywords:
Heavy exercise
;
Repeated
;
Twenty-four hours
;
Free fatty acids
;
Serum enzymes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The response of blood substrates and serum enzymes to repeated exercise over 24 h were studied in four trained males, aged from 25–33 years, with a $$\dot V$$ O2 max averaging 59.2 ml/kg/min. Exercise consisted of treadmill running for 6 min once per hour at approximately 95% $$\dot V$$ O2 max. Water was permitted ad libitum throughout the experiment and glucose during the final 12 h. Venous blood samples were obtained prior to and following every fourth work bout. Measurement of $$\dot V$$ O2 during the final 30 s of the first run was 4.11 l·min−1 and no significant deviation from the value was observed in any of the succeeding runs. Resting plasma free fatty acids increased approximately threefold over the duration of the experiment while blood glucose decreased from the fourth to the sixteenth work hour. A small increase in blood glucose occurred early in the glucose ingestion period, however, this did not persist and glucose levels showed progressive declines for the remainder of the experiment. Blood lactate and pyruvate values were elevated following each exercise bout. Repeated heavy work also elicited elevations in two serum enzymes, creatine phosphokinase and glutamic oxaloacetic transaminase. The declining respiratory exchange ratios suggest that over an extended period of time when progressive carbohydrate depletion is occurring and plasma levels of free fatty acids are elevated, fat oxidation can play an increasingly significant role in energy liberation during near maximal work.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00421341
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