The effect of sweat sample storage condition on sweat content

Area of Science:

• Sports Science
• Biochemistry
• Analytical Chemistry

Background:

• Immediate analysis of sweat samples is often limited by time and logistics.
• Understanding the impact of storage conditions on sweat composition is crucial for accurate research.

Purpose of the Study:

• To investigate how storage temperature and duration affect sweat electrolyte and metabolite concentrations.
• To determine optimal storage protocols for sweat sample analysis.

Main Methods:

• Twelve participants underwent a 60-minute cycling protocol in a controlled environment (33°C, 65% RH).
• Sweat samples were collected using the absorbent patch technique and stored at room temperature (~25°C) or frozen (-20°C) for varying durations (1h to 28 days).
• Concentrations of sodium, chloride, potassium, ammonia, lactate, and urea were measured.

Main Results:

• Sodium, chloride, potassium, and urea concentrations remained stable across all storage conditions.
• Lactate concentrations significantly decreased, and ammonia concentrations significantly increased after 28 days of storage at room temperature (25°C).
• Frozen storage (-20°C) for up to 28 days did not affect lactate and ammonia levels.

Conclusions:

• Storage temperature and duration significantly impact sweat lactate and ammonia concentrations.
• For reliable analysis of lactate and ammonia, sweat samples should not be stored at room temperature for more than 7 days.
• Freezing sweat samples at -20°C is recommended for extended storage up to 28 days to maintain the integrity of lactate and ammonia measurements.