Report

High Thermoregulatory Strain During Competitive Paratriathlon Racing in the Heat.

Strategies need to be implemented to reduce the thermal strain experienced by Para Triathletes during competition in the heat.

Lead academic:
Dr Ben Stephenson
Additional academics:
Dr Sven Hoekstra, Professor Vicky Tolfrey
Funder:
International Triathlon Union

Introduction:

Athletes with a spinal cord injury (SCI) have a high propensity for thermal strain caused by impaired autonomic function. However, other impairment groups are also at risk of thermal strain.

Competitive events in paratriathlon are commonly held in environments with high ambient temperatures; however, prolonged exercise in hot environments limits the capacity of the body to dissipate heat.

As no study has researched Paralympic athletes, it is not possible to discern any relationship between physical impairment and thermal strain imposed.

Study aim: To characterise the core temperature (Tc) and skin temperature (Tsk) responses to paratriathlon competition in the heat.

Methods:

The race consisted of a single lap, 750-m open-water lake swim, 21-km non-drafting cycle, and a 4.8-km run. Core temperature (Tc) was recorded at 30-second intervals in 28 mixed-impairment para triathletes during the competition in a hot environment, via an ingestible temperature sensor (Telemetric pill taken 6 hours pre-race).

In a subset of 9 athletes, Tsk was measured via temperature loggers placed on the pectoralis major and rectus femoris muscle belly.

Main findings:

  • Para triathletes face significant thermoregulatory strain.
  • A high proportion of athletes (57%) experienced self-reported symptoms of heat illness during competition.
  • During competition, Tc was significantly elevated from pre-race with marked increases during the run segment.
  • Depending upon their impairment, para triathletes may display a diminished capacity for evaporative heat loss, augmented metabolic heat production, or impaired pace awareness, thus elevating their risk of thermal strain and heat illness symptomatology.
  • In the subset of athletes in whom Tsk was measured, there was no significant change over time.
  • There was a significant difference in the Tsk changes across the race segments; specifically, the change was greater during cycling than running.
  • Wetsuit use resulted in a significantly elevated SWIMend and SWIMav Tc and may be linked to the incidence of heat illness.

Reference:

Stephenson BT, Hoekstra SP, Tolfrey K, Goosey-Tolfrey VL. High Thermoregulatory Strain During Competitive Paratriathlon Racing in the Heat. Int J Sports Physiol Perform. 2020 Feb 1;15(2):231-237. DOI: 10.1123/ijspp.2019-0116.

 

Image credit: © Paralympics GB