Diurnal physiological and immunological responses to a 10-km run in highly trained athletes in an environmentally controlled condition of 6\xa0\xb0C

Boukhemis Boukelia,M C Fogarty,G D Florida-James,R C R Davison

doi:10.1007/s00421-016-3489-5

Boukhemis Boukelia, M C Fogarty + Show 2 more

Open Access

https://doi.org/10.1007/s00421-016-3489-5

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Abstract

PurposeThe Clara cell protein CC16, secreted from Clara cells in the lung, is discussed as a potential biomarker for toxic effects on the airways. An increased concentration of CC16 in serum may be caused by increased permeability of the lungs. To investigate the changes in P-CC16 in response to an intense exercise bout performed at different times of day (9 am and 4 pm) of highly trained individuals.MethodUsing a crossover randomized design, 8 runners (mean VO2max 71 ml kg−1 min−1, SD 6) performed a 10-km time trial run, at 9 am and 4 pm, in an environmental chamber set at 6 °C. Lung function tests and blood sampling occurred at baseline, immediately post and 1 h post time trial.ResultDiurnal differences (P < 0.05) were found for blood neutrophil and lymphocyte counts; with higher values at 4 pm. P-CC16 was higher at the pre- and post-trial time point at 9 am compared to 4 pm. Lung function was not different between or within trials.ConclusionMorning trial in cold condition caused more physiological strain compared to the same trial in the evening. However, this extra stress caused by zeitgebers could be a useful strategy for athletes, coaches, and general population to improve their running performance and protect their health in cold conditions in the long-term plan.

Highlights

Trained athletes can be repeatedly exposed to cold air, inhalant irritants and allergens during training and racing (Helenius et al 2005)
Several studies have reported that the risk of upper respiratory tract infection (URTI) is elevated during periods of heavy training and in the period of one to two weeks following participation in endurance races (Nieman et al 1991; Foster 1998)
Airway inflammation can be detected by an increase in inflammatory markers, such as neutrophils, macrophages, inflammatory cytokines and Clara cell protein (CC16) (Bonsignore et al 2001)

Summary

Introduction

Trained athletes can be repeatedly exposed to cold air, inhalant irritants and allergens during training and racing (Helenius et al 2005) This exposure can result in airway epithelial injury (Bolger et al 2011), as a result of dehydration and physical stress applied to the airways during maximum effort in extreme environmental conditions (Bolger et al 2011). An array of immunological and physiological data analysed offers an important overview on the effect of exercising at a distinct time of day in cold condition It is relevant for coaches and athletes to be aware of how the time of day can affect various physiological and immunological responses and running performance. Understanding the diurnal cycle of athlete performance could be applied to testing sessions and competition times

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Discussion

Compliance with ethical standards