Int J Sports Med 2005; 26(10): 880-885
DOI: 10.1055/s-2005-837467
Immunology

© Georg Thieme Verlag KG Stuttgart · New York

The Effects of a High Carbohydrate Diet on Cortisol and Salivary Immunoglobulin A (s-IgA) During a Period of Increase Exercise Workload Amongst Olympic and Ironman Triathletes

R. J. S. Costa1 , G. E. Jones1 , K. L. Lamb1 , R. Coleman1 , J. H. H. Williams1
  • 1Chester Centre for Stress Research, University College Chester, England
Further Information

Publication History

Accepted after revision: November 25, 2004

Publication Date:
11 April 2005 (online)

Abstract

The present study observed the effects of a 6-day high carbohydrate (H-CHO) diet on salivary cortisol and IgA during a period of increased exercise workload. Thirty-two competitively trained male triathletes were randomly allocated into a self-selected (SS), or an H-CHO (12 g CHO kgbm-1 · day-1) dietary group. In addition to their training regimes, all subjects performed a 1-hour running exercise bout at 70 % V·O2max · d-1, for six days. Saliva samples were taken pre, immediately post, and morning post-exercise bout on days 1, 4, and 6. The concentrations of s-IgA and cortisol were determined by ELISA assays. There was a significant (p < 0.001) interaction between Group × Time for cortisol, with a marked increase in concentrations occurring in the SS dietary group pre to post exercise, and pre to morning post-exercise (p < 0.01). Conversely, a significant (p = 0.009) Group × Time interaction reflected higher post exercise s-IgA concentrations (p < 0.005) than pre exercise in the H-CHO diet group. Blood glucose concentration decreased pre to post exercise in the SS diet group (p < 0.01), whilst remaining stable in the H-CHO group. It is concluded that the consumption of a high CHO diet throughout a 6-day period of overtraining had a favourable effect on markers of immune activity and thereby reduced the susceptibility of these endurance athletes to upper respiratory tract infection URTI.

References

K. L. Lamb

Department of Sport and Exercise Sciences, University College Chester

Parkgate Road

Chester CH1 4BJ

United Kingdom

Phone: + 01244375444

Fax: + 0 12 44 39 28 89

Email: k.lamb@chester.ac.uk

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