B-20 Free Communication/Slide - Carbohydrate Metabolism and Health Wednesday, May 27, 2015, 1:00 PM - 3:00 PM Room: 26B
High-intensity interval exercise (HII) has been shown to elicit similar metabolic responses to moderate-intensity continuous exercise (MIC). While improved insulin sensitivity (Si) has previously been reported following a single exercise session, energy deficits caused by the exercise bout are rarely accounted for and may confound the true exercise-mediated effects on Si.
PURPOSE:To investigate the effects of HII vs. work-matched MIC on metabolic parameters of glucose control among African American (AA) and European American (EA) women in energy balance.
METHODS:A mixed-cohort of AA (n = 11) and EA (n = 11) premenopausal women completed a hyperinsulinemic-euglycemic clamp to assess Si along with fasting levels of glucose (GLU) and insulin (INS) across 4 time-points: baseline (BL), 8-16 weeks of aerobic training (TR), as well as, 22 hours following MIC at 50% peak VO2max and 22 hours following HII. The acute effects of exercise were performed at random in a room calorimeter. Energy intake was adjusted to insure EB while participants remained in the room calorimeter. Analysis of variance with repeated-measures were used to identify differences.
RESULTS:EB was within 24 kcal among conditions. Si [x10-4 min-1/(μIU/mL)] was not different in AAs while a significant time effect was observed in EAs with post hoc tests indicating the largest improvements following HII compared to all other conditions (BL, 10.5 ± 5.6; TR, 12.0 ± 4.1; MIC, 11.1 ± 5.0; HII, 14.5 ± 7.1; P = 0.04). Fasted GLU was similar across each time point for AAs and EAs. Additionally, fasted INS was not different in AAs or EAs.
CONCLUSIONS:Under energy balance conditions, Si was significantly improved in EAs 22 hours following an acute bout of HII despite no changes in fasting glucose or insulin. Our findings suggest that, during energy balance, EAs are more responsive to changes in Si by HII compared to AAs.
Supported by NIH Grants R01AG027084-01, R01AG027084-S, P30DK56336, P60DK079626, UL1RR025777.