- Pre-cooling is the process of reducing the body’s temperature before beginning exercise
- In this study, pre-cooling was found to reduce heart rate as well as surface and rectal temperatures during exercise
- Each horse responds differently to pre-cooling and an individual approach to managing heat stress in your horse is needed
- The FEI recommends pre-cooling eventing horses before cross-country in hot environmental conditions
Hot environmental conditions are known to affect the performance and health of athletes, especially in endurance-focused sports.
Additionally, we know that horses are at risk for heat strain when exercising in warm temperatures due to rapidly rising core temperatures that cannot be counteracted due to the horse’s limited ability to remove heat.
Cooling a horse after a workout or competition with chilled water is a widely accepted strategy to reduce the body’s temperature. However, are there opportunities to lower a horse’s body temperature before exercising to both enhance performance while also reducing the risk of heat-related injury?
Pre-cooling (lowering the body’s temperature before exercise) in human endurance athletes has been shown to lower the body’s starting core temperature, thus increasing the margin between the initial body temperature and the temperature at which health and/or performance becomes affected. In human athletes, the time to fatigue during exercise in hot conditions can be increased by lowering the body’s temperature prior to exercise.
Researchers from Utrecht University sought to study the effects of pre-cooling in a group of elite eventing horses. A total of 10 horses completed the study (6 horses at the CCI 1*–2* level and 4 horses at the CCI 4*–5* level).
The horses performed a warm-up (26 minutes in length) followed by moderate intensity canter sessions (two 4.5 minute canter sessions) on two days. Pre-cooling was given after the warm up but before the canter sessions and involved cold water rinsing for approximately eight minutes.
Five of the horses received pre-cooling on Day 1 followed by no pre-cooling on Day 2, while the other 5 horses received pre-cooling on Day 2 and no pre-cooling on Day 1. The temperature was 15.9 oC on Day 1 and 21.1 oC on Day 2.
Pre-cooling was found to reduce the heart rate by approximately 4 beats per minute during exercise. Interestingly, the researchers demonstrated that pre-cooling decreased the rectal temperature of horses, but only after 6 minutes of training—and the effect was greatest after 20 minutes of exercise. Pre-cooling also decreased the horse’s surface temperature (skin temperature) at the shoulders and hindquarters.
While there were interesting effects in these horses, the authors note that each horse responds to pre-cooling differently. Some horses may not react well to pre-cooling and it may not be a suitable option in some situations (due to time limitations or resource availability).
Findings from this study indicate a potential role for pre-cooling a horse’s body prior to performing exercise in moderate environmental conditions. Future research is needed i) to examine the effect of pre-cooling in hot conditions, ii) to assess the efficacy in other disciplines, and iii) to determine if certain horses respond better to pre-cooling than other horses
Research like this is critical for supporting the welfare and performance of horses around the world. The Sport Horse Research Foundation (SHRF) seeks to advance and direct scientific research and education to enhance the health, athletic potential, and career longevity of sport horses. Contributions donated to the SHRF are fully tax-deductible and funds are used to support cutting-edge and impactful scientific studies.
Klous L, Siegers E, van den Broek J, Folkerts M, Gerrett N, van Oldruitenborgh-Oosterbaan MS, Munsters C. Effects of pre-cooling on thermophysiological responses in elite eventing horses. Animals. 2020: 10(9): 1664. [TW1]