TY - JOUR
T1 - Effect of a 24-h continuous walking race on cardiac autonomic control
AU - Cottin, Francois
AU - Slawinski, Jean
AU - Lopes, Philippe
AU - Van de Louw, Andry
AU - Billat, Varonique
N1 - Funding Information:
Acknowledgments This study was supported by Polar France Electro and the Genopole of Evry. The authors thank the pleasant organization team of the 200 km of Bourges 2004 who have kindly welcomed us and allowed this investigation to be carried out.
PY - 2007/2
Y1 - 2007/2
N2 - This study investigated the relationships between walking speed and heart rate (HR) variability (HRV) in eleven subjects during a 24-h race. It was hypothesized that the nycthemeral rhythm on HR is preserved during the race. RR intervals and walking speed were measured. Fast Fourier transform was applied to samples of 1,024 successive RR intervals collected every hour from a HR monitor. Walking speed was averaged every hour and decreased (first lap: 8.8 ± 0.3 vs. last lap: 7.3 ± 0.8 km h-1, P < 0.001) with HR also decreasing (max at 19:00 h: 143 ± 9 vs. min at 7:00 h: 117 ± 14 beats min-1, P < 0.001) following a third order polynomial shape. HRV power spectral components followed distribution patterns similar to the mean RR during the race with a minimum in the early evening (19:00-20:00 h) and a maximum in the morning (5:00-8:00 h). Thus, as for mean RR, spectral components over time are also fitted to a third order polynomial regression. LF/HF ratio increased linearly (min = 0.5 ± 0.3, max = 2.8 ± 5.3, P = 0.02). Although mean HF peak did not decrease significantly over time, it was positively correlated with walking speed. In conclusion, this study showed that despite a constant decrease in walking speed, HR circadian rhythm is preserved during a continuous 24-h walking race. The short-term HRV components remain linked to HR whereas the LF/HF ratio increases linearly until the end of the race whatever HR is.
AB - This study investigated the relationships between walking speed and heart rate (HR) variability (HRV) in eleven subjects during a 24-h race. It was hypothesized that the nycthemeral rhythm on HR is preserved during the race. RR intervals and walking speed were measured. Fast Fourier transform was applied to samples of 1,024 successive RR intervals collected every hour from a HR monitor. Walking speed was averaged every hour and decreased (first lap: 8.8 ± 0.3 vs. last lap: 7.3 ± 0.8 km h-1, P < 0.001) with HR also decreasing (max at 19:00 h: 143 ± 9 vs. min at 7:00 h: 117 ± 14 beats min-1, P < 0.001) following a third order polynomial shape. HRV power spectral components followed distribution patterns similar to the mean RR during the race with a minimum in the early evening (19:00-20:00 h) and a maximum in the morning (5:00-8:00 h). Thus, as for mean RR, spectral components over time are also fitted to a third order polynomial regression. LF/HF ratio increased linearly (min = 0.5 ± 0.3, max = 2.8 ± 5.3, P = 0.02). Although mean HF peak did not decrease significantly over time, it was positively correlated with walking speed. In conclusion, this study showed that despite a constant decrease in walking speed, HR circadian rhythm is preserved during a continuous 24-h walking race. The short-term HRV components remain linked to HR whereas the LF/HF ratio increases linearly until the end of the race whatever HR is.
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U2 - 10.1007/s00421-006-0341-3
DO - 10.1007/s00421-006-0341-3
M3 - Article
C2 - 17115176
AN - SCOPUS:33846686541
VL - 99
SP - 245
EP - 250
JO - European Journal of Applied Physiology
JF - European Journal of Applied Physiology
SN - 1439-6319
IS - 3
ER -
