Multiple short bouts of exercise over 12-h period reduce glucose excursions more than an energy-matched single bout of exercise.
OBJECTIVE
Long, uninterrupted bouts of sedentary behavior are thought to negatively influence postprandial glucose and insulin concentrations. We examined the effects of a 1-h bout of morning exercise versus intermittent walking bouts of short duration on glucose excursions and insulin secretion over 12-h.


METHODS
Eleven young, obese individuals (18-35 years, BMI>30kg/m(2)) with impaired glucose tolerance were studied on three 12-h study days: 1) sedentary behavior (SED); 2) sedentary behavior with 1-h morning exercise (EX) at 60%-65% VO2peak; and 3) sedentary behavior with 12-hourly, 5-min intervals of exercise (INT) at 60%-65% VO2peak. Meals (1046kJ/meal) were provided every 2-h. Blood samples were collected every 10 min and measured for glucose, insulin, and c-peptide concentrations.


RESULTS
Glucose iAUC (12-h) was attenuated in the INT and SED conditions compared to the EX condition (P<0.05). Glucose concentrations were higher in the EX compared to the SED condition for ~150min (20% of the study day), and comparison of the EX-INT study days revealed that glucose concentrations were greater for~240min (~1/3 of the 12-hday). In the SED condition, the 12-h insulin iAUC was ~15% higher (P<0.05) compared to the INT and EX conditions. Insulin production rate was found to increase ~20% with INT exercise vs. the SED and EX condition (P<0.05).


CONCLUSIONS
Short, frequent periods of exercise attenuated glucose excursions and insulin concentrations in obese individuals to a greater degree than an equal amount of exercise performed continuously in the morning.
Department of Exercise Science, Syracuse University, Syracuse, NY, USA; Department of Exercise and Rehabilitative Sciences, Slippery Rock University, Slippery Rock, PA, USA.
Michael
M
Holmstrup
School of Psychology and Exercise Science, Murdoch University, Murdoch, Western Australia.
Timothy
T
Fairchild
Department of Exercise Science, Syracuse University, Syracuse, NY, USA.
Stefan
S
Keslacy
Department of Internal Medicine, SUNY Upstate Medical University, Syracuse, NY, USA.
Ruth
R
Weinstock
Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO, USA. Electronic address: kanaleyj@missouri.edu.
Jill
J
Kanaley
D000293:Adolescent; D000328:Adult; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D015444:Exercise; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D009765:Obesity / Q000097:blood* / Q000503:physiopathology; D055815:Young Adult
D001786:Blood Glucose; D007328:Insulin
Glucose; Insulin; Obesity; Physical activity; Sedentary