Real-time monitoring of biometric responses during a 200-km ultra-endurance race across the desert

<p dir="ltr">Ultra-endurance sports challenge athlete health, with these risks exacerbated by environmental extremes and/or remoteness of competition. Therefore, this study aimed to use real-time monitoring technology to characterise and monitor physiological/biomechanical responses during SAMLA 2023, a 200-km multidiscipline (swim, run, bike, and kayak) ultra-endurance race, encompassing cool and warm desert environmental conditions (16°C–28°C). Within a cross-sectional observational study design, 18 males (total entrants: 318) were instrumented with wearable/ingestible sensors measuring physiological [heart rate and core (Tc)/skin (Tsk) temperature], biomechanical [gait] and location-based [Global Positioning System (GPS)] metrics. Sensors connected to a smartphone application via Bluetooth, which saved and transmitted data to a cloud-based dashboard in real-time. Participants were on-course for an accumulated ∼668 h. ∼662 h of GPS data were displayed in real-time with the longest individual data capture of ∼57 h. Physiological/biomechanical data were acquired for x̄: ∼42% (range: ∼38%–∼49%) of the participant on-course time. Hypo/hyperthermic Tc's were seen (x̄: 37.8°C range: 35.7°C–39.2°C). Tsk (28°C: 11.7°C–38.4°C) in response to the varied in-race environmental challenges (16°C–28°C ambient temperature) and heart rate (111 b·min−1: 37 b·min−1–179 b·min−1) varied markedly. One participant was hospitalised without presentation in physiological data. Biomechanical data had significant data loss and quality issues and are not presented. Developments in real-time monitoring technology, acknowledging limitations observed here (physiological/biomechanical data acquisition), may allow combined in-race GPS and physiological data (e.g., Tc/Tsk) to be used during ultra-endurance sport to prospectively protect athlete health. GPS/physiological data alone may not identify medical emergencies, and medical teams must remain alert to medical events<br><br><b>Highlights</b></p><p><br></p><ul><li>Athletes can experience significant physiological and thermoregulatory strain in ultra endurance events, even when exercise intensity is relatively low and environmental conditions seem favourable for a safe race from a thermoregulatory stress (heat and cold) perspective.</li><li>The use of real-time monitoring technology was largely successful providing evidence that in-race physiological data visualisation is possible across long duration races in remote locations. However, in its current form, it suffers limitations that restrict implementation on a wider scale.</li><li>On-course medical emergencies will not always present with physiological indicators becoming progressively alarming. Medical teams must remain prepared to respond to medical events even when athletes' biometric data are available in real-time and do not provide alerts.</li></ul><p></p>