Performance and pacing during cycle exercise in hyperthermic and hypoxic conditions

J.D. Périard, Sebastien Racinais

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Introduction: This study examined the influence of alterations in maximal oxygen uptake (V·O2max) in mediating performance and pacing during prolonged self-paced exercise. Methods: Twelve well-trained cyclists completed a 750-kJ time trial in temperate (COOL, 18°C), hot (HOT, 35°C), and hypoxic (HYP, 18°C; FiO2, 0.145) conditions, creating models with a stable, progressively decreasing, and acutely decreased V·O2max, respectively. Results: Trial completion was faster in COOL (48.2 ± 5.7 min) compared with HOT (55.4 ± 5.0 min) and HYP (60.1 ± 6.5 min) (P < 0.001), with HOT being faster than HYP (P = 0.028). Core temperature reached 39.0°C ± 0.6°C (COOL), 39.8°C ± 0.5°C (HOT), and 38.5°C ± 0.4°C (HYP; P < 0.01). Power output during COOL was higher than HOT from 40% of work completed onward (P < 0.05) and for the entirety of HYP (P < 0.001), in which it was lower than HOT at 20%–30% (P < 0.05). Normalized power output during COOL and HYP varied by ~13% and ~16%, respectively, whereas a ~27% variation occurred in HOT. V·O2 in COOL was higher than HOT from 70% onward (P < 0.01) and higher than HYP throughout exercise (P < 0.001). Relative to baseline V·O2max (%V·O2max) in normoxia (COOL and HOT) and hypoxia (HYP), %V·O2max during HOT (78% ± 8%) was lower than COOL (84% ± 7%; P = 0.005) and HYP (87% ± 5%; P = 0.003). Conclusions: Despite an acutely reduced V·O2max and power output in HYP, pacing and %V·O2max were similar to COOL. In contrast, the progressive decrease in V·O2max and power output in HOT resulted in a more variable pacing pattern with %V·O2max decreasing throughout exercise. These data support the premise that pacing is associated with maintaining an optimal performance intensity, in conjunction with acute and progressive alterations in V·O2max
Original languageEnglish
Pages (from-to)845-853
Number of pages9
JournalMedicine and Science in Sports and Exercise
Volume48
Issue number5
DOIs
Publication statusPublished - 2016
Externally publishedYes

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@article{ec87fb260e4e41a48e6860fe5ae95717,
title = "Performance and pacing during cycle exercise in hyperthermic and hypoxic conditions",
abstract = "Introduction: This study examined the influence of alterations in maximal oxygen uptake (V·O2max) in mediating performance and pacing during prolonged self-paced exercise. Methods: Twelve well-trained cyclists completed a 750-kJ time trial in temperate (COOL, 18°C), hot (HOT, 35°C), and hypoxic (HYP, 18°C; FiO2, 0.145) conditions, creating models with a stable, progressively decreasing, and acutely decreased V·O2max, respectively. Results: Trial completion was faster in COOL (48.2 ± 5.7 min) compared with HOT (55.4 ± 5.0 min) and HYP (60.1 ± 6.5 min) (P < 0.001), with HOT being faster than HYP (P = 0.028). Core temperature reached 39.0°C ± 0.6°C (COOL), 39.8°C ± 0.5°C (HOT), and 38.5°C ± 0.4°C (HYP; P < 0.01). Power output during COOL was higher than HOT from 40{\%} of work completed onward (P < 0.05) and for the entirety of HYP (P < 0.001), in which it was lower than HOT at 20{\%}–30{\%} (P < 0.05). Normalized power output during COOL and HYP varied by ~13{\%} and ~16{\%}, respectively, whereas a ~27{\%} variation occurred in HOT. V·O2 in COOL was higher than HOT from 70{\%} onward (P < 0.01) and higher than HYP throughout exercise (P < 0.001). Relative to baseline V·O2max ({\%}V·O2max) in normoxia (COOL and HOT) and hypoxia (HYP), {\%}V·O2max during HOT (78{\%} ± 8{\%}) was lower than COOL (84{\%} ± 7{\%}; P = 0.005) and HYP (87{\%} ± 5{\%}; P = 0.003). Conclusions: Despite an acutely reduced V·O2max and power output in HYP, pacing and {\%}V·O2max were similar to COOL. In contrast, the progressive decrease in V·O2max and power output in HOT resulted in a more variable pacing pattern with {\%}V·O2max decreasing throughout exercise. These data support the premise that pacing is associated with maintaining an optimal performance intensity, in conjunction with acute and progressive alterations in V·O2max",
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pages = "845--853",
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Performance and pacing during cycle exercise in hyperthermic and hypoxic conditions. / Périard, J.D.; Racinais, Sebastien.

In: Medicine and Science in Sports and Exercise, Vol. 48, No. 5, 2016, p. 845-853.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Performance and pacing during cycle exercise in hyperthermic and hypoxic conditions

AU - Périard, J.D.

AU - Racinais, Sebastien

N1 - Cited By :4 Export Date: 23 May 2017

PY - 2016

Y1 - 2016

N2 - Introduction: This study examined the influence of alterations in maximal oxygen uptake (V·O2max) in mediating performance and pacing during prolonged self-paced exercise. Methods: Twelve well-trained cyclists completed a 750-kJ time trial in temperate (COOL, 18°C), hot (HOT, 35°C), and hypoxic (HYP, 18°C; FiO2, 0.145) conditions, creating models with a stable, progressively decreasing, and acutely decreased V·O2max, respectively. Results: Trial completion was faster in COOL (48.2 ± 5.7 min) compared with HOT (55.4 ± 5.0 min) and HYP (60.1 ± 6.5 min) (P < 0.001), with HOT being faster than HYP (P = 0.028). Core temperature reached 39.0°C ± 0.6°C (COOL), 39.8°C ± 0.5°C (HOT), and 38.5°C ± 0.4°C (HYP; P < 0.01). Power output during COOL was higher than HOT from 40% of work completed onward (P < 0.05) and for the entirety of HYP (P < 0.001), in which it was lower than HOT at 20%–30% (P < 0.05). Normalized power output during COOL and HYP varied by ~13% and ~16%, respectively, whereas a ~27% variation occurred in HOT. V·O2 in COOL was higher than HOT from 70% onward (P < 0.01) and higher than HYP throughout exercise (P < 0.001). Relative to baseline V·O2max (%V·O2max) in normoxia (COOL and HOT) and hypoxia (HYP), %V·O2max during HOT (78% ± 8%) was lower than COOL (84% ± 7%; P = 0.005) and HYP (87% ± 5%; P = 0.003). Conclusions: Despite an acutely reduced V·O2max and power output in HYP, pacing and %V·O2max were similar to COOL. In contrast, the progressive decrease in V·O2max and power output in HOT resulted in a more variable pacing pattern with %V·O2max decreasing throughout exercise. These data support the premise that pacing is associated with maintaining an optimal performance intensity, in conjunction with acute and progressive alterations in V·O2max

AB - Introduction: This study examined the influence of alterations in maximal oxygen uptake (V·O2max) in mediating performance and pacing during prolonged self-paced exercise. Methods: Twelve well-trained cyclists completed a 750-kJ time trial in temperate (COOL, 18°C), hot (HOT, 35°C), and hypoxic (HYP, 18°C; FiO2, 0.145) conditions, creating models with a stable, progressively decreasing, and acutely decreased V·O2max, respectively. Results: Trial completion was faster in COOL (48.2 ± 5.7 min) compared with HOT (55.4 ± 5.0 min) and HYP (60.1 ± 6.5 min) (P < 0.001), with HOT being faster than HYP (P = 0.028). Core temperature reached 39.0°C ± 0.6°C (COOL), 39.8°C ± 0.5°C (HOT), and 38.5°C ± 0.4°C (HYP; P < 0.01). Power output during COOL was higher than HOT from 40% of work completed onward (P < 0.05) and for the entirety of HYP (P < 0.001), in which it was lower than HOT at 20%–30% (P < 0.05). Normalized power output during COOL and HYP varied by ~13% and ~16%, respectively, whereas a ~27% variation occurred in HOT. V·O2 in COOL was higher than HOT from 70% onward (P < 0.01) and higher than HYP throughout exercise (P < 0.001). Relative to baseline V·O2max (%V·O2max) in normoxia (COOL and HOT) and hypoxia (HYP), %V·O2max during HOT (78% ± 8%) was lower than COOL (84% ± 7%; P = 0.005) and HYP (87% ± 5%; P = 0.003). Conclusions: Despite an acutely reduced V·O2max and power output in HYP, pacing and %V·O2max were similar to COOL. In contrast, the progressive decrease in V·O2max and power output in HOT resulted in a more variable pacing pattern with %V·O2max decreasing throughout exercise. These data support the premise that pacing is associated with maintaining an optimal performance intensity, in conjunction with acute and progressive alterations in V·O2max

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DO - 10.1249/MSS.0000000000000839

M3 - Article

VL - 48

SP - 845

EP - 853

JO - Medicine Science in Sports Exercise

JF - Medicine Science in Sports Exercise

SN - 0195-9131

IS - 5

ER -