IGF‐I and IGFBP-3 during Continuous and Interval Exercise (original) (raw)

Int J Sports Med 2008; 29(3): 182-187
DOI: 10.1055/s-2007-965114

Physiology & Biochemistry

© Georg Thieme Verlag KG Stuttgart · New York

Further Information

Publication History

accepted after revision January 9, 2007

Publication Date:
13 September 2007 (online)

Abstract

The purpose of this research was to compare changes in circulating levels of total IGF‐I and IGFBP-3 during continuous, moderate-intensity exercise (CE) and high-intensity interval exercise (IE) of equal duration. Ten healthy males completed 2 exercise sessions and a resting control session (R) in random order. The CE was 20 minutes of cycling at 60 - 65 % of V·O2max. During IE, subjects cycled at 80 - 85 % of V·O2max for 1 minute followed by 40 seconds of active recovery, with the cycle repeated for a total of 20 minutes. In each session blood samples were drawn at - 10, 0, 5, 10, 20 and 30 minutes. Both IGF‐I and IGFBP-3 increased during exercise (p < 0.05) and repeated measures ANOVA revealed a significant effect for session (IE, CE > R, p < 0.05). Area under the curve (AUC) analyses showed no difference in IGF‐I between sessions, however, the IGFBP-3 AUC was significantly greater during IE than R (p < 0.05). These results suggest interval and continuous exercise will result in similar changes in circulating IGF‐I and IGFBP-3. This could be beneficial to individuals who can exercise longer and at a higher intensity in intervals than would be possible using a continuous protocol.

Key words

exercise intensity - insulin‐like growth factor‐I - insulin‐like growth factor binding protein‐3 - interval exercise - cycling

References

Dr. Jennifer L. Copeland

Department of Kinesiology
University of Lethbridge

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Canada

Phone: + 1 40 33 17 28 04

Fax: + 1 40 33 80 18 39

Email: jennifer.copeland@uleth.ca