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Echocardiographic changes following active heat acclimation.
Parsons, Iain T; Snape, Daniel; O'Hara, John; Holdsworth, David A; Stacey, Michael J; Gall, Nick; Chowienczyk, Phil; Wainwright, Barney; Woods, David R.
  • Parsons IT; Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK; School of Cardiovascular Medicine and Sciences, King's College London, UK. Electronic address: iain.parsons@kcl.ac.uk.
  • Snape D; Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, UK. Electronic address: d.snape@leedsbeckett.ac.uk.
  • O'Hara J; Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, UK. Electronic address: j.ohara@leedsbeckett.ac.uk.
  • Holdsworth DA; Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK. Electronic address: david.holdsworth@nhs.net.
  • Stacey MJ; Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK. Electronic address: michael.stacey@nhs.net.
  • Gall N; School of Cardiovascular Medicine and Sciences, King's College London, UK. Electronic address: nicholasgall@nhs.net.
  • Chowienczyk P; School of Cardiovascular Medicine and Sciences, King's College London, UK. Electronic address: phil.chowienczyk@kcl.ac.uk.
  • Wainwright B; Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, UK. Electronic address: barney.wainwright@leedsbeckett.ac.uk.
  • Woods DR; Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK; Research Institute for Sport, Physical Activity and Leisure, Carnegie School of Sport, Leeds Beckett University, UK. Electronic address: DoctorDRWoods@aol.com.
J Therm Biol ; 93: 102705, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-739933
ABSTRACT
Heat adaption through acclimatisation or acclimation improves cardiovascular stability by maintaining cardiac output due to compensatory increases in stroke volume. The main aim of this study was to assess whether 2D transthoracic echocardiography (TTE) could be used to confirm differences in resting echocardiographic parameters, before and after active heat acclimation (HA). Thirteen male endurance trained cyclists underwent a resting blinded TTE before and after randomisation to either 5 consecutive daily exertional heat exposures of controlled hyperthermia at 32°C with 70% relative humidity (RH) (HOT) or 5-days of exercise in temperate (21°C with 36% RH) environmental conditions (TEMP). Measures of HA included heart rate, gastrointestinal temperature, skin temperature, sweat loss, total non-urinary fluid loss (TNUFL), plasma volume and participant's ratings of perceived exertion (RPE). Following HA, the HOT group demonstrated increased sweat loss (p = 0.01) and TNUFL (p = 0.01) in comparison to the TEMP group with a significantly decreased RPE (p = 0.01). On TTE, post exposure, there was a significant comparative increase in the HOT group in left ventricular end diastolic volume (p = 0.029), SV (p = 0.009), left atrial volume (p = 0.005), inferior vena cava diameter (p = 0.041), and a significant difference in mean peak diastolic mitral annular velocity (e') (p = 0.044). Cardiovascular adaptations to HA appear to be predominantly mediated by improvements in increased preload and ventricular compliance. TTE is a useful tool to demonstrate and quantify cardiac HA.
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Full text: Available Collection: International databases Database: MEDLINE Main subject: Sweating / Exercise / Thermotolerance / Heart Type of study: Controlled clinical trial / Randomized controlled trials Limits: Adult / Humans / Male Language: English Journal: J Therm Biol Year: 2020 Document Type: Article

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Full text: Available Collection: International databases Database: MEDLINE Main subject: Sweating / Exercise / Thermotolerance / Heart Type of study: Controlled clinical trial / Randomized controlled trials Limits: Adult / Humans / Male Language: English Journal: J Therm Biol Year: 2020 Document Type: Article