Author(s): PIRAZZI, A., FERRARO, O.E., ASSALONI, R., CUM, S., BRUNATO, B., CARNEVALE PELLINO, V., GIURIATO, M., ALBERICO, A., CAVALLO, C., GATTI, A., MINARDI, E., DEL BIANCO, M., VANDONI, M., Institution: UNIVERSITY OF PAVIA, Country: ITALY, Abstract-ID: 2710

INTRODUCTION:
HYROX is an indoor high-intensity fitness competition that combines running intervals and resistance exercise stations. Prolonged near-maximal exertion and limited recovery are associated with significant metabolic stress. In people with type 1 diabetes (T1D), these demands challenge insulin therapy and glycemic stability. In particular, in paired competition formats such as the HYROX Double, workload alternation between teammates involves repeated high-intensity efforts with with substantial anaerobic contribution. This study aimed to analyze cardiovascular and mechanical load and to describe intra- and post-competition glycemic responses during an official HYROX Double competition in two athletes with T1D.
METHODS:
Two trained female athletes with T1D (Athlete 1: 30 years, T1D duration 20 years; Athlete 2: 36 years, T1D duration 32 years) competed in an official HYROX Double competition after a 24-week structured training program. Training was performed four times per week and included aerobic exercise, resistance training and combined sessions designed to simulate race-specific demands. Both athletes were managed with continuous subcutaneous insulin infusion (CSII; Tandem) integrated with a Dexcom G7 continuous glucose monitoring (CGM) system. IInterstitial glucose was continuously monitored pre-, intra-, and post-race, while physiological load was assessed by heart rate (HR) recorded with a Garmin Sportwatch.
RESULTS:
The athletes completed the race in 01:14:54, achieving a 40th place in their category. Mean and peak HR were 140 and 185 bpm in athlete 1, while Athlete 2 reached 175 and 188 bpm. High-intensity workload predominated in both athletes, with an average of 48% of total race time accumulated in power zone 5 (>229 W). Pre-race glycemia concentrations were 185 mg/dL in athlete 1 and 146 mg/dL in athlete 2. CGM showed a progressive intra-race increase in interstitial glucose in both athletes, with a larger glycemic excursion in athlete 1. At race completion, glucose concentrations reached approximately 260–270 mg/dL in athlete 1 and 220–230 mg/dL in athlete 2. In the first hour post-exercise, glucose peaked at 334 mg/dL in athlete 1 and stabilized at 210 mg/dL in athlete 2. Two hours post-race, the glycemic trend remained elevated in athlete 1 at 260–280 mg/dL, whereas it declined toward 180–190 mg/dL in athlete 2. No carbohydrate intake was reported during the race.
CONCLUSION:
Participation in a HYROX Double competition appears feasible in athletes with T1D but it is associated with marked hyperglycemic responses due to the anaerobic exercise demands. These findings underline the necessity of structured training program to optimize glycemic control in high-intensity fitness competitions. Moreover, an individualized balance between training load, insulin therapy and nutritional strategies is crucial. This case series provides novel practical insights into glycemic management during HYROX competition in people with T1D.