Effects of prolonged hypoxia and bed rest on appetite and appetite-related hormones. (1st December 2016)

• Record Type: Journal Article
• Authors: Debevec, Tadej; Simpson, Elizabeth J.; Mekjavic, Igor B.; Eiken, Ola; Macdonald, Ian A.
• Is Part Of: Appetite. Volume 107(2016)
• Page Start: 28
• Page End: 37
• Publication Date: 2016-12-01
• Subjects: Hypoxemia -- High altitude anorexia -- Bed rest -- Inactivity -- Appetite regulation; HAMB hypoxic confinement combined with daily moderate-intensity exercise -- NBR bed rest in normoxia -- HBR bed rest in hypoxia -- CSS composite satiety score -- PYY peptide YY -- GLP-1 glucagon-like peptide 1 -- AUC incremental area under the curve -- FiO2 inspired O2 fraction -- PiO2 inspired O2 partial pressure -- VAS visual analogue score; Food habits -- Periodicals; Appetite -- Periodicals; Appetite disorders -- Periodicals; Electronic journals; 306.4613
• DOI: 10.1016/j.appet.2016.07.005
• Languages: English
• ISSNs: 0195-6663

Abstract

Abstract: Environmental hypoxia and inactivity have both been shown to modulate appetite. To elucidate the independent and combined effects of hypoxia and bed rest-induced inactivity on appetite-related hormones and subjective appetite, eleven healthy, non-obese males underwent three experimental interventions in a cross-over and randomized fashion: 1) Hypoxic confinement combined with daily moderate-intensity exercise (HAMB, Fi O2 = 0.141 ± 0.004; Pi O2 = 90.0 ± 0.4 mmHg) 2) Bed rest in normoxia (NBR, Fi O2 = 0.209; Pi O2 = 133.1 ± 0.3 mmHg) and 3) Bed rest in hypoxia (HBR, Fi O2 = 0.141 ± 0.004; Pi O2 = 90.0 ± 0.4 mmHg). A mixed-meal tolerance test (MTT), followed by an ad libitum meal were performed before (Pre) and after 16-days (Post) of each intervention. Composite satiety scores (CSS) during the MTT were calculated from visual analogue scores, while fasting and postprandial concentrations of total ghrelin, peptide YY (PYY), glucagon-like peptide-1 (GLP-1) and leptin were quantified from arterialized-venous samples. Postprandial CSS were significantly lower at Post compared to Pre in NBR only (P < 0.05) with no differences observed in ad libitum meal intakes. Postprandial concentrations and incremental area under the curve (AUC) for total ghrelin and PYY were unchanged following all interventions. Postprandial GLP-1 concentrations were only reduced at Post following HBR (P < 0.05) with resulting AUC changes being significantly lower compared to HAMB (P < 0.01). Fasting leptin was reduced following HAMB (P < 0.05) with no changes observed following NBR and HBR. These findings suggest that independently, 16-day of simulated altitude exposure (∼4000 m) and bed rest-induced inactivity do not significantly alter subjective appetite or ad libitum intakes. The measured appetite-related hormones following both HAMB and HBR point to a situation of hypoxia-induced appetite stimulation, although this did not reflect in higher ad libitum intakes. Clinical Trial Registration Number: NCT02293772 .