Fluid Intake and Hydration Responses to Mass Participation Gravel Cycling

Gravel cycling is a relatively new cycling discipline, with the Union Cycliste Internationale (UCI) hosting their first World Championships in 2022. Gravel races combine features of road racing, cyclocross, and mountain biking, including terrain of varying technical difficulty, long distances, substantial elevation gain, obstacles, and limited opportunities to stop for in-race nutrition. This study assessed hydration responses to gravel races of three different distances. Data were collected on saliva osmolarity (SOsm), body mass (BM), fluid intake, and nutrition knowledge at a gravel cycling race in April 2023. A total of 121 participants completed pre-race surveys, 53 provided pre-race measures of BM and SOsm, and 38 participants completed post-race testing. Only 22.6% (n = 12) of participants were hydrated before the race, with 56.6% mildly dehydrated (n = 30), 18.9% moderately dehydrated (n = 10), and 1.9% severely dehydrated (n = 1). Post-race, 15% (n=6) were still hydrated, 20% (n = 8) were mildly dehydrated, 47.5% (n = 19) were moderately dehydrated, and 17.5% (n = 7) were severely dehydrated. Analyses revealed significant decreases in BM and increases in SOsm from pre- to post-exercise in the two longer race distances (p < 0.05). There was a significant effect of race distance on energy, fluid, carbohydrate, and sodium intake (p < 0.05). Sweat rates were not different (p > 0.05). Our results revealed an effect of race distance on BM losses, SOsm, and energy, fluid, carbohydrate, and sodium intakes. Future studies could inform optimal feeding and hydration strategies.