Journal Opens Access to Heat and Humidity Research Ahead of the Tokyo Olympics

Bay horse exercising in the heat

To help vets protect elite horses from the extreme conditions expected at the Tokyo Olympics, the Equine Veterinary Journal is providing free access to a Special Collection of eleven landmark papers covering the health and welfare of horses competing in hot and humid conditions.

The COVID-19-delayed Tokyo Olympics will take place during the Japanese Summer, in temperatures likely to reach more than 41°C (105°F). The factor of concern, however, is that Tokyo’s heat is usually accompanied by very high humidity. While horses are cope well with extreme heat in dry conditions, the reliance on sweating to cool the body down through evaporation is not effective when the hot air is saturated with moisture.

And with extreme heatwaves becoming more frequent around the world, all veterinarians, sports leaders and event officials, horse trainers and owners, have the opportunity to understand the major advances made in the last two decades on the prevention of dehydration, heat stress and heat exhaustion.

This upgrade is crucial because the new recommendations on cooling horses effectively and exercising safely in hot conditions are proven to protect horses but unfortunately, there is still plenty of misinformation circulating around that is still recommending outdated and dangerous practices, putting horses at risk of fatal heat stroke and compromising horse sports’ social licence to operate.

Everyone in the horse can use this opportunity to update their knowledge on working and competing horses in the heat, understand the importance of acclimatisation, protect horses who are travelling on hot days, maintaining hydration, confirm the best strategies for warming-up and cooling down, and learn to use of electrolytes correctly.

Event organisers and sports governing bodies in all disciplines, at any level, will find the research that explains  why the event conditions should be evaluated using the Wet Bulb Globe Thermometer (WBGT) in the sun index rather than on heat and/or humidity measures alone.

In addition, horse owners are encouraged to learn to recognise signs of heat stress and recognise that the most effective way to cool a hot horse is by pouring cold water (15 degrees C or less and ideally 5 degrees C) all over the body’s surface continuously (without stopping to scrape or walk) until the horse’s temperature restores to safe levels.

The EVJ’s Special Collection Preparing for Tokyo Olympics contains 11 highly relevant papers and provides the evidence-base to the latest recommended best practices. It is accompanied by a comprehensive editorial forward from Dr Christopher Elliott.

“This is not the first time that extreme heat and humidity has challenged the viability of Equestrian events at the Olympic Games,” said Christopher Elliott. “It is vital that we learn from the past to ensure the welfare of equine athletes in the future.”

The Special Collection highlights the ground-breaking research which followed the 1992 Barcelona Olympics.

“This work revolutionised our understanding of managing equine athletes in hot and humid conditions,” said Christopher. “It optimised identification and management of heat stress and allowed practical solutions to cooling methods to be established, enabling the successful running of the 1996 Atlanta Olympics.”

In the lead up to the 2008 Beijing Olympics another concerted effort by veterinary researchers further advanced understanding and it is on the back of this work that recent literature of equine heat stress and optimisation of cooling methods has been established.

The special collection explores:

  1. Physiological, metabolic and biochemical responses of horses competing in the speed and endurance phase of a CCI**** 3‐day‐event
  2. Physiological responses to the endurance test of a 3‐day‐event during hot and cool weather
  3. Physiological responses of horses competing at a modified 1 Star 3‐day‐event
  4. Adaptations to daily exercise in hot and humid ambient conditions in trained Thoroughbred horses
  5. Sweating rate and sweat composition during exercise and recovery in ambient heat and humidity
  6. Physiological responses of horses to a treadmill simulated speed and endurance test in high heat and humidity before and after humid heat acclimation
  7. Comparison between two post exercise cooling methods
  8. Contributions of equine exercise physiology research to the success of the 1996 Equestrian Olympic Games: a review
  9. An index of the environmental thermal load imposed on exercising horses and riders by hot weather conditions
  10. Use of the Wet Bulb Globe Temperature (WBGT) Index to quantify environmental heat loads during Three‐day‐event competitions
  11. Risk factors for exertional heat illness in Thoroughbred racehorses in flat races in Japan (2005–2016)

Professor Celia Marr, Editor of the EVJ said: “Prevention is always better than cure: this special collection provides much excellent research and knowledge gained from previous events. We must ensure that we use it to best effect to keep the equine athletes competing in extreme climates in Tokyo this summer safe, cool, healthy and performing at their best.”

The Special Collection is ‘Free to Read’ which will enable readers without institutional access to read the article but downloading will still be behind a paywall.

It can be viewed and downloaded here .


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