Effects of Environmental Heat Stress (35 °C) with Simulated Air Movement on the Thermoregulatory Responses during a 4‐km Cycling Time Trial

Altareki, Noureddin A.; Drust, Barry; Atkinson, Greg; Cable, N. Timothy; Gregson, W.

doi:10.1055/s-2008-1038768

Cited by 39 publications

(41 citation statements)

References 37 publications

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“…Heat-stress (Figure 5) had a significant, negative impact on time-trial performance from a sample of 14 MPO data points per trial section MPO and for the whole trial MPO across 11 included studies (MD = −24.79 W, 95% CI = −39.52 to −10.06, p = 0.001) (Tatterson et al, 2000; Tucker et al, 2004; Abbiss et al, 2008; Altareki et al, 2009; Peiffer and Abbiss, 2011; Périard et al, 2011; Castle et al, 2012; Périard and Racinais, 2015, 2016; Schmit et al, 2016; VanHaitsma et al, 2016). Trial section data demonstrated a gradual decline in MPO (and Pacing Index Change Score) as the trials progressed under hot conditions compared to the control condition ( Figure 12 ).…”

Section: Resultsmentioning

confidence: 99%

“…In some of the studies, the exposure to the heat-stress prior to the time-trial (i.e., during the standardized warm-up) was ≤ 15 min in duration (Castle et al, 2012; Schmit et al, 2016; VanHaitsma et al, 2016) or longer (Abbiss et al, 2008; Altareki et al, 2009). However, in the remaining studies either no mention was made as to participants being exposed to the heat-stress prior to the time-trials, or they did not expose their participants to heat-stress in the warm-up period (Tatterson et al, 2000; Tucker et al, 2004; Peiffer and Abbiss, 2011; Périard et al, 2011; Périard and Racinais, 2015, 2016).…”

Section: Discussionmentioning

confidence: 99%

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Effect of Environmental and Feedback Interventions on Pacing Profiles in Cycling: A Meta-Analysis

et al. 2016

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In search of their optimal performance athletes will alter their pacing strategy according to intrinsic and extrinsic physiological, psychological and environmental factors. However, the effect of some of these variables on pacing and exercise performance remains somewhat unclear. Therefore, the aim of this meta-analysis was to provide an overview as to how manipulation of different extrinsic factors affects pacing strategy and exercise performance. Only self-paced exercise studies that provided control and intervention group(s), reported trial variance for power output, disclosed the type of feedback received or withheld, and where time-trial power output data could be segmented into start, middle and end sections; were included in the meta-analysis. Studies with similar themes were grouped together to determine the mean difference (MD) with 95% confidence intervals (CIs) between control and intervention trials for: hypoxia, hyperoxia, heat-stress, pre-cooling, and various forms of feedback. A total of 26 studies with cycling as the exercise modality were included in the meta-analysis. Of these, four studies manipulated oxygen availability, eleven manipulated heat-stress, four implemented pre-cooling interventions and seven studies manipulated various forms of feedback. Mean power output (MPO) was significantly reduced in the middle and end sections (p < 0.05), but not the start section of hypoxia and heat-stress trials compared to the control trials. In contrast, there was no significant change in trial or section MPO for hyperoxic or pre-cooling conditions compared to the control condition (p > 0.05). Negative feedback improved overall trial MPO and MPO in the middle section of trials (p < 0.05), while informed feedback improved overall trial MPO (p < 0.05). However, positive, neutral and no feedback had no significant effect on overall trial or section MPO (p > 0.05). The available data suggests exercise regulation in hypoxia and heat-stress is delayed in the start section of trials, before significant reductions in MPO occur in the middle and end of the trial. Additionally, negative feedback involving performance deception may afford an upward shift in MPO in the middle section of the trial improving overall performance. Finally, performance improvements can be retained when participants are informed of the deception.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effect of Environmental and Feedback Interventions on Pacing Profiles in Cycling: A Meta-Analysis

et al. 2016

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“…Table 2 summarizes results of studies that examined the impact of heat stress on submaximal intensity aerobic performance employing either TTE or TT protocols (5,19,59,64,90,110,159,160,162,218,240,295,306,307,314). Again there is a considerable range of ambient temperatures for the control (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) • C) and heat stress (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40) • C) conditions.…”

Section: History Of Research Related To Aerobic Performancementioning

confidence: 99%

Performance in the Heat—Physiological Factors of Importance for Hyperthermia‐Induced Fatigue

Nybo

Rasmussen

Sawka

2014

Comprehensive Physiology

262

299

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This article presents a historical overview and an up-to-date review of hyperthermia-induced fatigue during exercise in the heat. Exercise in the heat is associated with a thermoregulatory burden which mediates cardiovascular challenges and influence the cerebral function, increase the pulmonary ventilation, and alter muscle metabolism; which all potentially may contribute to fatigue and impair the ability to sustain power output during aerobic exercise. For maximal intensity exercise, the performance impairment is clearly influenced by cardiovascular limitations to simultaneously support thermoregulation and oxygen delivery to the active skeletal muscle. In contrast, during submaximal intensity exercise at a fixed intensity, muscle blood flow and oxygen consumption remain unchanged and the potential influence from cardiovascular stressing and/or high skin temperature is not related to decreased oxygen delivery to the skeletal muscles. Regardless, performance is markedly deteriorated and exercise-induced hyperthermia is associated with central fatigue as indicated by impaired ability to sustain maximal muscle activation during sustained contractions. The central fatigue appears to be influenced by neurotransmitter activity of the dopaminergic system, but inhibitory signals from thermoreceptors arising secondary to the elevated core, muscle and skin temperatures and augmented afferent feedback from the increased ventilation and the cardiovascular stressing (perhaps baroreceptor sensing of blood pressure stability) and metabolic alterations within the skeletal muscles are likely all factors of importance for afferent feedback to mediate hyperthermia-induced fatigue during submaximal intensity exercise. Taking all the potential factors into account, we propose an integrative model that may help understanding the interplay among factors, but also acknowledging that the influence from a given factor depends on the exercise hyperthermia situation.

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“…The authors concluded that heat stress was associated with a reduced power output during self-paced exercise in highly trained men. Another cycling study examined the influence of environmental heat stress (35°C) on 4-km cycling time trial performance (Altareki, Drust, Atkinson, Cable, & Gregson, 2009). Mean performance time was reduced in 35°C compared to 13°C (95% CI of difference = 4.0 to 10.6 s; P < 0.01).…”

Section: Introductionmentioning

confidence: 99%

Validation of the SenseWear Armband in different ambient temperatures

Hoye

Boen

Lefevre

2014

Journal of Sports Sciences

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This study examines the validity of the SenseWear Armband in different temperatures using the old (SenseWear v2.2) and newest version of the algorithm (SenseWear v5.2) against indirect calorimetry (IC). Thirty-nine male and female students (21.1 ± 1.41 years) completed an exercise trial in 19°C, 26°C and 33°C consisting of 5 min standing followed by alternating walking/running at 35% and 65% of their maximal oxygen uptake. The accuracy of the algorithms was evaluated by comparing estimated energy expenditure (EE) to IC using a mixed-model design. No difference was reported in EE between the different temperatures for IC. Both algorithms estimated EE significantly higher when exercising at high intensity in 33°C compared to 19°C. Compared to IC, SenseWear v2.2 accurately estimated EE during standing and light intensity exercise but underestimated EE when exercising in a hot environment and at high intensity. SenseWear v5.2 showed a difference when exercising at high intensity in thermoneutral and warm conditions. The new algorithm improved EE estimation in hot environments and at high intensity compared to the old version. However, given the inherent inaccuracy of the EE estimates of SenseWear, greater weight should be given to direct monitor outputs rather than the ability of a monitor to estimate EE precisely.

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Effects of Environmental Heat Stress (35 °C) with Simulated Air Movement on the Thermoregulatory Responses during a 4‐km Cycling Time Trial

Cited by 39 publications

References 37 publications

Effect of Environmental and Feedback Interventions on Pacing Profiles in Cycling: A Meta-Analysis

Effect of Environmental and Feedback Interventions on Pacing Profiles in Cycling: A Meta-Analysis

Performance in the Heat—Physiological Factors of Importance for Hyperthermia‐Induced Fatigue

Validation of the SenseWear Armband in different ambient temperatures

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