The effects of intermittent liquid meal feeding on selected hormones and substrates during intense weight training.
This study examined the effects of feeding a liquid meal during weight training on selected hormones and substrates. Ten male subjects were given a meal (MW) or nonnutritive placebo (W) before and intermittently during a 2-hr weight training session, and a meal before and intermittently during 2 hours of rest (M). Serum insulin increased from 12.2 +/- 1.2 and 11.2 +/- 1.3 before feeding to 37.2 +/- 4.8 and 45.0 +/- 5.0 mU.ml-1 during exercise in MW and M, respectively, and remained elevated for 120 min. Insulin remained at resting levels in W throughout the experiment. Glucose increased from 5.20 +/- 0.16 and 4.82 +/- 0.20 before feeding to 6.23 +/- 0.30 and 6.0 +/- 0.36 mmol.l-1 at the beginning of exercise in MW and M. Glucose declined during the first 15 min of exercise in MW and M but remained at or above resting levels for 120 min in MW. Lactate increased above 5.9 mmol.l-1 in W and MW during exercise. Glucagon remained unchanged in all groups. Perceived exertion during exercise was 8.5 +/- 0.16 for MW and 8.3 +/- 0.18 for W. Feeding a liquid meal before and during weight training exercise can increase serum insulin and maintain blood glucose for a prolonged period.
Dept. of Physical Education, California State University, Chico 95926.
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Fahey
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Hoffman
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Colvin
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Lauten
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015444:Exercise / Q000502:physiology; D005526:Food, Formulated; D005934:Glucagon / Q000097:blood; D006801:Humans; D007328:Insulin / Q000097:blood*; D007773:Lactates / Q000097:blood*; D019344:Lactic Acid; D008297:Male; D012996:Solutions; D014891:Weight Lifting
D001786:Blood Glucose; D007328:Insulin; D007773:Lactates; D012996:Solutions; D019344:Lactic Acid; D005934:Glucagon