Whole body, regional fat accumulation, and appetite-related hormonal response after hypoxic training

Abstract

The present study was conducted to determine change in regional fat accumulation and appetite-related hormonal response following hypoxic training. Twenty sedentary subjects underwent hypoxic (n = 9, HYPO, FiO(2) = 15%) or normoxic training (n = 11, NOR, FiO(2) = 20·9%) during a 4-week period (3 days per week). They performed a 4-week training at 55% of maximal oxygen uptake (V·O(2max)) for each condition. Before and after the training period, V·O(2max), whole body fat mass, abdominal fat area, intramyocellular lipid content (IMCL), fasting and postprandial appetite-related hormonal responses were determined. Both groups showed a significant increase in V·O(2max) following training (P<0·05). Whole body and segmental fat mass, abdominal fat area, IMCL did not change in either group. Fasting glucose and insulin concentrations significantly reduced in both groups (P<0·05). Although area under the curve for the postprandial blood glucose concentrations significantly decreased in both groups (P<0·05), the change was significantly greater in the HYPO group than in the NOR group (P<0·05). Changes in postprandial plasma ghrelin were similar in both groups. A significant reduction of postprandial leptin response was observed in both groups (P<0·05), while postprandial glucagon-like peptide-1 (GLP-1) concentrations increased significantly in the NOR group only (P<0·05). In conclusion, hypoxic training for 4 weeks resulted in greater improvement in glucose tolerance without loss of whole body fat mass, abdominal fat area or IMCL. However, hypoxic training did not have synergistic effect on the regulation of appetite-related hormones.

Keywords: appetite regulation; endurance training; intramyocellular lipid content; normobaric hypoxia; postprandial glucose control.