The main objectives are to determine sweat sodium concentration [Na+], whole body sweat rate (WBSR) and rate of sweat sodium loss (RSSL) in female athletes aged 13 and above during their normal planned training session across various sports (basketball, soccer, volleyball, cheer, flag football and softball).

The testing procedures will follow the standardized Gatorade Sports Sciences GSSI sweat testing protocol using the absorbent sweat patch technique, to measure local sweat [Na+], which will be normalized to whole-body sweat [Na+]. Whole-body sweat rate (WBSR) will be calculated based on changes in exercise body mass, pre to post training, and adjusted for food and fluid intake, as well as urine and stool loss. The rate of sweat sodium loss (RSSL) will be determined as the product of sweat [Na+] and WBSR.

Secondary outcomes are pre-exercise hydration status measured by urine specific gravity (USG) and estimation of menstrual cycle phase collected by self-report date of last menstrual cycle.

Athletes will complete a single day of testing, unless a repeat test is requested by the team's performance staff. In this case, athletes will undergo the exact same protocol as described above.

Inclusion Criteria:

Subject is female

• Subject is 13yrs+
• Subject has been cleared for sport participation by their personal or team physician and/or coach-led practice/training.
• Subject is participating in sport on the youth/ amateur/ collegiate/professional/elite level
• If under 18, a parental/guardian consent form will be completed.

Exclusion Criteria:

• As this study is undertaken at the athletes training facility, the medical staff at the team/club will advise on who should/ should not take part.
• Subject has an allergy to adhesives (e.g., experiences rash reactions to typical adhesive bandages

Reason female only is lack of sports science sweat research data specific to female athletes

Healthy female athletes in coach-led team sports