Hydration isn’t glamorous, and it can be a hard sell to players focused on the ball, but it matters: the body is over 60% water, and poor fluid balance undermines performance, recovery and sleep.
The Gatorade Sports Science Institute (GSSI) has spent years working with elite squads — past partners include Manchester City, Brazil and Barcelona — helping clubs quantify individual hydration and fueling needs. The message is simple: inadequate fluid intake eventually hurts performance. That personalised data is what persuaded Wrexham’s head of medical performance and sports science, Kevin Mulholland, to bring the programme in. Testing before and after matches highlights which players are most likely to dehydrate late in games and helps the staff plan to keep players effective through the 96–97 minutes when many matches are decided.
I visited Wrexham’s SToK Cae Ras on a day both the men’s and women’s first teams were having a ‘‘sweat test,’’ part of the club’s routine checks a few times each season. GSSI schedules these assessments around intense training sessions designed to replicate match demands and the resulting sweat loss. Testing starts with a weigh-in and a urine sample to establish body-mass change and baseline hydration.
Dr Ian Rollo, principal scientist at GSSI, points out that even players who say they have drunk before testing can show mild dehydration on analysis. The players then complete 15 minutes on an exercise bike followed by pitch drills that mimic football’s stop-start demands, raising heart rate and sweat production. GSSI applies Gx sweat patches to the arm and back; each patch collects sweat and a tiny tube in the patch visibly fills during the session. Those samples are analysed for sweat volume and electrolyte content to produce individualised recommendations.
For high-intensity work GSSI usually suggests a standard Gatorade sports drink that provides fluid, carbohydrates and electrolytes. On lighter days, when extra carbs aren’t needed, a Gatorade Hydration Booster supplies fluid and electrolytes without the additional carbohydrates.
After training there’s another weigh-in and a record of how much the player drank. The calculation is straightforward: weight change minus fluid consumed equals fluid loss. An app analyses the sweat-patch results and immediately gives a per-hour drinking target to maintain hydration. Results often surprise players — sweat rates vary widely.
Rollo explains why: bigger, more muscular players and those working harder produce more metabolic heat and sweat more. American footballers often show very high rates because of muscle mass, heavy kit and hot conditions, but footballers can also end matches with soaked shirts. High sweat rate isn’t inherently good or bad — it’s an individual trait that needs managing.
For Wrexham the benefit is practical: tailored hydration plans aim to prevent late-game drop-off, reduce fatigue and lower injury risk. It rarely makes headlines, but when margins are fine over a season, personalised fluid strategies can be a subtle factor in where a team finishes.