The 2024 summer of sports has been dominated by one central theme: extreme heat and humidity caused by climate change. In and amongst the amazing athletic achievements, it has been impossible to ignore the suffocating heat. The Paris Olympics saw temperatures of 36℃ (96.8℉), which research group World Weather Attribution said would not have been possible without human-induced climate change. The UEFA Euros and the Copa America also suffered from extreme temperatures. In the U.S., the heat wave was so extreme that assistant referee Humberto Panjoj collapsed during the match between Canada and Peru, and FC Barcelona and Uruguay star defender Ronald Araujo asked to be substituted due to dehydration.
Climate change is our unfortunate (manmade) reality. While there is a host of solutions that can help play a role in mitigating the increase in global temperature — from the immediate cessation of fossil fuel production to the implementation of circular economy models — for elite athletes, these solutions do not change the excessive heat they face every day. This is why the conversation about athlete health and the ability to host major sporting events in a warming world is increasingly prevalent. To consistently perform at the highest level, athletes must find ways to rapidly adapt to rising temperatures (and even this will not be enough if temperatures continue to increase). Enter, CORE.
Founded in 2019, by engineer Wulf Glatz, CORE is a wearables company that has developed the only non-invasive technology capable of measuring a human’s core body temperature. According to Ross McGraw, Global VP and Head of CORE, Glatz founded the company after watching a triathlete at the 2019 Frankfurt Ironman collapse within sight of the finish line due to heat stress. He was determined to use his scientific background to “help athletes better regulate their core body temperatures.”
Through a simple clip-on monitor connected to a mobile app (no pills or probes required), CORE technology “detects heat moving from or into the body.” The sensor provides real-time data to athletes and coaches that goes beyond skin temperature and looks at heat strain index, heat zones, and heat training load. These data points allow athletes to understand the specific amount of strain their body is under as it tries to cool itself, and facilitates heat training protocols that enable them to adapt their body to higher temperatures and increase their thermal fitness. CORE can be used before workouts, or during a full workout and can even be worn 24/7 if an athlete wants continuous data on their core temperature and heat adaptation.
CORE’s heat strain index (HSI) quantifies the strain the body is under as it tries to cool itself. The HSI combines skin and core temperatures to give the most accurate reading possible in real-time. As explained by Puck Alkemade, physiologist and study coordinator at CORE, each athlete’s HSI will differ depending on mass, height, and innate heat tolerance, an element still not fully understood by researchers. An athlete’s HSI is placed into one of four heat zones. Roughly speaking, training in heat zone one there is no noticeable strain. Heat zone two is still comfortable and safe for athletes, although there may be some decline in performance. Training in heat zone three is demanding and through an efficient protocol (60 minutes a day) will create physiological adaptations that improve performance in extreme heat, while training in zone four is dangerous and should be avoided. These zones are designed as a guide that help athletes (professional and amateur) to tailor their training accordingly.
On July 8th, 2024, CORE updated its uses adding the Heat Adaptation Score. According to CORE, “the new metric…compiles the results of the Heat Strain Index and Heat Zones to make tracking progress easier, offer guidance to refine training methods for better heat adaptation, and inform pacing in hot events.” Essentially, it shows athletes how adapted they are to performing in each heat zone and serves to adjust training times and loads.
The app update was released ahead of the Paris Olympics in line with the recommendation from the British Association for Sustainable Sport’s (BASIS) Rings of Fire II report which stated that enhanced technology should be used to monitor heat and body temperature to mitigate the dangerous effects of extreme heat in sporting competitions.
Before the Paris Olympics, CORE was already used by 65% of the UCI World Tour, as well as Lisa Brenauer, the gold medalist in cycling at the Tokyo Olympics, Kristian Blummenfelt, the defending Olympic gold medalist in triathlon, and Remco Evenepoel, the Belgian who went on to win two gold medals at this summer’s games in Men’s Road Race. However, McGraw says the “goal is for it to be useful for everyone,” not just top-tier athletes. He added that “the world is getting warmer for all of us,” so the company is trying to make its product more accessible, noting “We can’t have a huge impact on the world if we only work with a subset of people.”
As heat and humidity continue to increase, it is important that athletes understand how to train properly in such conditions. While some Olympians and other high-earning athletes may have access to the technology needed to train safely, most amateur athletes do not, and the consequences can be life-threatening. CORE’s technology helps level the playing field so all athletes can track their training and understand when they can push themselves in the heat, and when they are approaching a dangerous heat strain threshold.
As Alkemade says, “Most athletes do not have a team of sports scientists on staff. So we want to make it easier for athletes to learn and use thermal data like the pros and for coaches to give more specific direction.” The technology is affordable too, the standard core sensor which clips onto shorts, shirts or any athletic apparel costs $284.95.
In the short-term, CORE will help athletes adapt their bodies to the new reality and limit potential health risks. Luckily adaptability is one of humans’ best traits. Unfortunately, without serious reductions in fossil fuel production and consumption, human adaptation will not be enough and the very ability to play sports consistently in the natural environment will be under threat.
