Energy restriction has a high failure rate, which may be related to energy regulating hormones (acylated ghrelin, insulin, etc.) that stimulates energy intake (EI) and suppresses energy expenditure (EE). An alternative is to maintain EI and raise EE through exercise. The impact of short-term exercise training on energy regulating hormones has not been systematically studied. In addition, women do not lose body fat with exercise training, whereas men do lose body fat. The sex difference may be related to energy regulating hormones. The purposes of this proposal were, (1) to determine the independent effects of exercise with and without energy replaced on energy regulating hormones (acylated ghrelin, insulin, etc.) and appetite responses, and (2) to determine whether sex differences exists. Concentrations and area under the curve (AUC) of these hormones were measured in overweight/obese individuals (9M, 9W) during a meal tolerance test after a 1-day baseline. Using a counter-balanced, crossover design, measurements were repeated after 4 consecutive days of exercise (EE = ∼750 kcal/d-1 for men, ∼600 kcal/d-1 for women) with exercise energy added back to maintain energy balance (BAL) and, 4 consecutive days of the exercise without energy added back to maintain energy deficit (DEF). In men, acylated ghrelin AUC was not different between baseline, DEF, and BAL. In men, compared to baseline insulin AUC was lower after DEF (p<0.05), but not BAL. In women, compared to baseline acylated ghrelin AUC was higher after DEF and BAL (p<0.05). Women vs. men had a greater change from in acylated ghrelin after DEF and BAL. In women, compared to baseline insulin AUC was lower after DEF and lower after BAL (p<0.05). Appetite ratings were lower after BAL compared to baseline or DEF in men. In women, there was no change in appetite ratings. In women short-term exercise training regardless of energy state affects energy regulating hormones and appetite in the directions expected to stimulate energy intake and suppress energy expenditure. In men however, exercise alone has no impact on energy regulating hormones or appetite when energy balance was maintained and the effect of energy deficit was less pronounced than in women.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-5039 |
| Date | 01 January 2008 |
| Creators | Hagobian, Todd Alan |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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