Consecutive days of exercise decrease insulin response more than a single exercise session in healthy, inactive men

• Published in: European journal of applied physiology Vol. 119; no. 7; pp. 1591 - 1598
• Main Authors: Castleberry, Todd, Irvine, Christopher, Deemer, Sarah E., Brisebois, Matthew F., Gordon, Ryan, Oldham, Michael D., Duplanty, Anthony A., Ben-Ezra, Vic
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-07-2019; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Biomedicine; Glucose; Glucose tolerance; Human Physiology; Insulin; Occupational Medicine/Industrial Medicine; Original Article; Peptides; Sports Medicine; Walking; Exercise pattern; Glucose; Consecutive days; Insulin; Incremental area under the curve; Single session
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s00421-019-04148-z

Purpose
It is reported that a single bout of exercise can lower insulin responses 12–24 h post-exercise; however, the insulin responses to alternate or consecutive bouts of exercise is unknown. Thus, the purpose of this study was to examine the effect of exercise pattern on post-exercise insulin and glucose responses following a glucose challenge.
Methods
Ten male participants (
n
 = 10, mean ± SD, Age 29.5 ± 7.7 years; BMI 25.7 ± 3.0 kg/m
2
) completed three exercise trials of walking for 60 min at ~ 70% of
V
O
2max
. The trials consisted of: three consecutive exercise days (3CON), three alternate exercise days (3ALT), a single bout of exercise (SB), and a no exercise control (
R
). Twelve to fourteen hours after the last bout of exercise or
R
, participants completed a 75 g oral glucose tolerance test (OGTT) and blood was collected at 30 min intervals for the measurement of glucose, insulin, and C-peptide.
Result
Calculated incremental area under the curve (
i
AUC) for glucose and C-peptide was not different between the four trials. Insulin
i
AUC decreased 34.9% for 3CON compared to
R
(
p
 < 0.01).
Conclusion
Three consecutive days of walking at ~ 70%
V
O
2max
improved insulin response following an OGTT compared to no exercise. It is possible, that for healthy males, the effect of a single bout of exercise or exercise bouts separated by more than 24 h may not be enough stimulus to lower insulin responses to a glucose challenge.