GSSI research finds widespread dehydration, sodium replacement and carbohydrate intake shortfalls, strengthening calls for more personalised guidance for active women.
Nearly half of the women assessed in Gatorade’s first “Body of Science” study began exercising already dehydrated, while many failed to replace enough sodium or consume recommended amounts of carbohydrate during activity.
The Gatorade Sports Science Institute (GSSI) will present the findings at the American Society for Nutrition Annual Meeting on 26 July. Gatorade’s research arm launched the multi-year “Body of Science” programme to address gaps in women’s hydration and sports nutrition research.
Hundreds of women participating in sports and activities including basketball, football and ice hockey took part. Researchers examined their hydration before exercise, sweat rates, sodium losses and carbohydrate intake.
The data from our first ‘Body of Science’ study is clear – these aren’t small gaps between what women’s bodies need and how they’re fueling. They’re the difference between feeling your best and unknowingly falling short.
Being armed with this data will help us conduct deeper, more targeted research in future ‘Body of Science’ work.”
Dr Kimberly Stein, Senior Principal Scientist at GSSI
Women begin exercise at a deficit
The study found that 43 percent of participants arrived at workouts dehydrated, suggesting many began exercising with an existing fluid deficit.
Although participants consumed what GSSI considered adequate amounts of fluid, they replaced an average of only around 20 percent of the sodium they lost during exercise. The institute recommends replacing close to 50 percent.
Basketball players recorded the highest sodium losses among the sports measured. GSSI said insufficient sodium replacement could contribute to muscle cramps, fatigue and impaired performance.
Researchers also found that 57 percent of participants consumed less carbohydrate than GSSI recommends during exercise, while half consumed none. The institute advises consuming between 30g and 60g of carbohydrates per hour during activity.
Although women recorded lower average sweat rates than men, results varied considerably between individuals. GSSI said this challenged broad assumptions about women’s hydration needs and strengthened the case for more personalised guidance.
The findings point to a wider information gap. Research commissioned by Lidl GB in June 2025 found that almost 80 percent of women surveyed had never received guidance on fuelling for exercise. Among regular exercisers, 67 percent had received no tailored training or recovery advice, while 71 percent wanted more education on female sports nutrition.
“The data from our first ‘Body of Science’ study is clear – these aren’t small gaps between what women’s bodies need and how they’re fueling. They’re the difference between feeling your best and unknowingly falling short,” said Dr Kimberly Stein, Senior Principal Scientist at GSSI. “Being armed with this data will help us conduct deeper, more targeted research in future ‘Body of Science’ work.”
Research expands across life stages
GSSI has created more detailed categories for female sweat rates, which it plans to use as a benchmark for future research and individualised hydration recommendations.
The institute is now extending the programme to examine women during premenopause, perimenopause and menopause, with more than 500 participants already involved. The next phase will explore whether hydration and fuelling needs change across these life stages, addressing another area where female-specific evidence remains limited.
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