title: Human plasma ghrelin levels increase during a one-year exercise program.
abstract: Weight loss resulting from decreased caloric intake raises levels of the orexigenic hormone, ghrelin. Because ingested nutrients suppress ghrelin, increased ghrelin levels in hypophagic weight loss may result from decreased inhibitory input by ingested food, rather than from lost weight. We assessed whether ghrelin levels increase in response to exercise-induced weight loss without decreased caloric intake. We randomized 173 sedentary, overweight, postmenopausal women to an aerobic exercise intervention or stretching control group. At baseline, 3 months, and 12 months, we measured body weight and composition, food intake, cardiopulmonary fitness (maximal oxygen consumption), leptin, insulin, and ghrelin. Complete data were available for 168 women (97%) at 12 months. Exercisers lost 1.4 +/- 0.4 kg (P < 0.05 compared with baseline; P = 0.01 compared with stretchers) and manifested a significant, progressive increase in ghrelin levels, whereas neither measure changed among stretchers. Ghrelin increased 18% in exercisers who lost more than 3 kg (P < 0.001). There was no change in caloric intake in either group and no effect on ghrelin of exercise per se independent of its impact on body weight. In summary, ghrelin levels increase with weight loss achieved without reduced food intake, consistent with a role for ghrelin in the adaptive response constraining weight loss and, thus, in long-term body weight regulation.
authors.affiliation: Department of Medicine, Division of Metabolism, University of Washington, Veterans Affairs Puget Sound Health Care System, Seattle, Washington 98108, USA.
authors.forename: Karen E
authors.initials: KE
authors.lastname: Foster-Schubert
authors.forename: Anne
authors.initials: A
authors.lastname: McTiernan
authors.forename: R Scott
authors.initials: RS
authors.lastname: Frayo
authors.forename: Robert S
authors.initials: RS
authors.lastname: Schwartz
authors.forename: Kumar B
authors.initials: KB
authors.lastname: Rajan
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yasui
authors.forename: Shelley S
authors.initials: SS
authors.lastname: Tworoger
authors.forename: David E
authors.initials: DE
authors.lastname: Cummings
mesh_terms: D015992:Body Mass Index; D049628:Body Size; D001835:Body Weight; D004038:Diet, Reducing; D002149:Energy Intake; D015444:Exercise / Q000502:physiology*; D005260:Female; D054439:Ghrelin; D006801:Humans; D008875:Middle Aged; D036361:Peptide Hormones / Q000097:blood*; D017698:Postmenopause; D013997:Time Factors
chemical_list: D054439:Ghrelin; D036361:Peptide Hormones