Ivory Coast Football Club
Hydration status can fluctuate considerably during tournament football as players transition between training, recovery, travel and competition. However, hydration monitoring is often interpreted from isolated measurements, despite the possibility that an athlete’s hydration status may change substantially prior to competition. This case study examined longitudinal hydration patterns in elite international football players during the 2026 FIFA World Cup.
Twenty-six male international players from the Ivory Coast National Team were monitored across four World Cup matches. Hydration was assessed using salivary osmolarity (SOSM) on Match Day-1 (MD-1) and Match Day (MD). In total, 189 hydration readings were collected. SOSM values >65 mOsm were classified as dehydrated.
Findings:
Hydration status varied substantially both between and within individual players:
- On MD-1, mean mOsm was 66.8, with 49.5% of measurements classified as dehydrated
- On MD, mean mOsm was 70.4, with 63.6% of measurements classified as dehydrated
- Of 64 paired MD-1 and MD measurements, 63.3% of players who were dehydrated on MD-1 remained dehydrated on MD
- 61.8% of players classified as hydrated on MD-1 were dehydrated on MD
The principal finding is that hydration status was highly dynamic within individual players despite relatively stable squad-level averages. A single MD-1 measurement therefore should not be interpreted as confirmation that an athlete will remain adequately hydrated by MD. These findings support using SOSM as a serial, individualised monitoring tool, with greater emphasis placed on each player’s trajectory across repeated measurements rather than isolated values or squad averages.
Practical Interpretations:
Players who repeatedly demonstrate an increase in SOSM between MD-1 and MD may warrant targeted monitoring and individualised hydration strategies in the lead-up to competition.