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Impact of intensified training and carbohydrate supplementation on immunity and markers of overreaching in highly trained cyclists

  • Sophie Killer
    ,
  • Ida S. Svendsen
    ,
  • James M. Carter
    ,
  • Rebecca K. Randell
    ,
  • Asker E. Jeukendrup
    ,
  • Michael Gleeson
  • Loughborough University
    ,
  • PepsiCo
Research Output: Contribution to journal Article Peer-review

Open access

Abstract

Purpose: To determine effects of intensified training (IT) and carbohydrate supplementation on overreaching and immunity. Methods: In a randomized, double-blind, crossover design, 13 male cyclists (age 25 ± 6 years, (Formula presented.) 72 ± 5 ml/kg/min) completed two 8-day periods of IT. On one occasion, participants ingested 2 % carbohydrate (L-CHO) beverages before, during and after training sessions. On the second occasion, 6 % carbohydrate (H-CHO) solutions were ingested before, during and after training, with the addition of 20 g of protein in the post-exercise beverage. Blood samples were collected before and immediately after incremental exercise to fatigue on days 1 and 9. Results: In both trials, IT resulted in decreased peak power (375 ± 37 vs. 391 ± 37 W, P < 0.001), maximal heart rate (179 ± 8 vs. 190 ± 10 bpm, P < 0.001) and haematocrit (39 ± 2 vs. 42 ± 2 %, P < 0.001), and increased plasma volume (P < 0.001). Resting plasma cortisol increased while plasma ACTH decreased following IT (P < 0.05), with no between-trial differences. Following IT, antigen-stimulated whole blood culture production of IL-1α was higher in L-CHO than H-CHO (0.70 (95 % CI 0.52–0.95) pg/ml versus 0.33 (0.24–0.45) pg/ml, P < 0.01), as was production of IL-1β (9.3 (95 % CI 7–10.4) pg/ml versus 6.0 (5.0–7.8) pg/ml, P < 0.05). Circulating total leukocytes (P < 0.05) and neutrophils (P < 0.01) at rest increased following IT, as did neutrophil:lymphocyte ratio and percentage CD4+ lymphocytes (P < 0.05), with no between-trial differences. Conclusion: IT resulted in symptoms consistent with overreaching, although immunological changes were modest. Higher carbohydrate intake was not able to alleviate physiological/immunological disturbances.

Publication Information

Output type

Research Output: Contribution to journal Article Peer-review

Original language

English

Pages from-to (Number of pages)

Pages 867-877

Journal (Volume, Issue Number)

European Journal of Applied Physiology (Volume 116, Issue 5)

Publication milestones

  • Accepted/In press - 09/02/2016
  • Published - 23/02/2016

Publication status

Published - 23/02/2016

ISSN

1439-6319

External Publication IDs

  • handle.net: 10547/624790
  • Scopus: 84959140349

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