Publication Date

2013-12-09

Availability

Open access

Embargo Period

2013-12-09

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PHD)

Department

Kinesiology and Sport Sciences (Education)

Date of Defense

2013-11-18

First Committee Member

Kevin A. Jacobs

Second Committee Member

Luigi F. Meneghini

Third Committee Member

Nicholas D. Myers

Fourth Committee Member

Arlette C. Perry

Abstract

Objective: To examine the efficacy of a 10-s maximal sprint performed immediately prior to and following a 40-min, moderate-intensity bout of exercise, as a means of maintaining plasma glucose concentration during both exercise and 120 min of recovery in those with type 1 diabetes mellitus (T1DM). Research Design and Methods: Seven moderately active males with T1DM performed a continuous graded exercise test on a cycle ergometer to determine peak power output (Wpeak). Subjects then reported to the laboratory on two separate occasions after an overnight 8-h fast and either rested (CON) or performed a 10-s maximal effort sprint (150% Wpeak) immediately prior to and again immediately following (SP) a 40-min bout of steady-state exercise (55% of Wpeak, ~70% VO2peak) on a cycle ergometer. Trials were performed in a randomized and counterbalanced order. Results: Plasma glucose concentration decreased during exercise in CON and was significantly lower than baseline at 40 min of exercise (-2.5 ± 0.9 mM, p < 0.05) and throughout recovery. While plasma glucose concentration tended to decrease during exercise in the SP trial (-0.9 ± 1.2 mM), values were never significantly different than baseline. Plasma glucose concentration did not change from the end of exercise throughout recovery in either CON or SP. Plasma lactate concentration increased significantly from baseline to end of exercise in both CON and SP and was significantly higher in SP than CON (~1.5 mM, p < 0.05) throughout exercise and 15 min into recovery. Plasma epinephrine concentration increased significantly (5- to 8-fold, p < 0.05) from rest to exercise and there were no differences between conditions. Conclusions: A brief maximal sprint attenuated the decline in plasma glucose concentration during moderate intensity exercise, but plasma glucose concentration did not change from the end of exercise throughout recovery in either CON or SP . The protective effects of the brief maximal sprint before exercise appear to be attributable more to the increased availability of plasma lactate than a potentiation of the catecholamine response. Brief maximal sprints may aid individuals with uncomplicated TIDM to better maintain normoglycemia during exercise and gain the greatest benefits from regular aerobic exercise.

Keywords

T1DM, exercise hypoglycemia, glucoregulation

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