Abstract
This study determined if varying physical activity (PA) the day prior to an oral glucose
tolerance test (OGTT) differentially influenced postprandial glucose and insulin kinetics.
Fifteen healthy, young adults participated in three OGTT trials the morning after
performing 50% (LOW), 100% (HABITUAL), or 150% (HIGH) of their habitual PA (determined
by 7-day pedometry). Trials were randomized and separated by at least 1-wk. For each
OGTT trial, blood glucose and insulin were measured after an overnight fast and at
30-min intervals for 2 h following ingestion of the glucose beverage. Between-trial
differences were analyzed using a general linear model with repeated measures. Subjects
successfully achieved the desired percentage of habitual steps prior to each trial:
LOW: 51±5%, HABITUAL: 99±6%, and HIGH: 149±9%. Fasting blood glucose and glucose total
area under the curve (AUC) did not differ between trials. Serum insulin AUC was lower
(p<0.05) following the HIGH (34,158±8,786 pmol·min·L−1) compared to the LOW (40,738±9,276 pmol·min·L−1) trial. No differences were observed when the LOW and HIGH trials were compared to
HABITUAL. These data suggest that varying the PA level (from 50 to 150% of habitual
PA) the day prior to an OGTT influences the insulin (but not blood glucose) response
to an OGTT.
Key words
insulin sensitivity - sedentary behavior - pedometry - accelerometry - metabolic health
