Exercise-associated hyponatraemia on the Kokoda Trail

Area of Science:

• Exercise Physiology
• Sports Medicine
• Environmental Health

Background:

• Exercise-associated hyponatraemia (EAH) is a potentially dangerous condition characterized by low serum sodium levels.
• While EAH is recognized in endurance athletes, its prevalence in trekkers undertaking challenging, multi-day hikes is less understood.
• The Kokoda Trail presents unique environmental stressors, including heat and humidity, which may influence hydration status and electrolyte balance.

Purpose of the Study:

• To investigate the prevalence of exercise-associated hyponatraemia among individuals hiking the Kokoda Trail.
• To identify potential risk factors associated with hyponatraemia in this trekking population.

Main Methods:

• A cross-sectional study was conducted involving 191 trekkers on the Kokoda Trail, Papua New Guinea.
• Blood samples were collected and analyzed immediately using point-of-care technology.
• Samples were taken approximately two days' walk from each terminus of the trail.

Main Results:

• A prevalence of 1.6% (95% CI 0.5-4.5%) for mild hyponatraemia (serum sodium < 135 mmol/L) was observed.
• Participants diagnosed with hyponatraemia reported significantly higher fluid intake (median 6 L) compared to those with normal sodium levels (median 3.3 L).
• This suggests a potential link between excessive fluid consumption and the development of hyponatraemia during trekking.

Conclusions:

• Exercise-associated hyponatraemia is a relevant clinical finding in trekkers on the Kokoda Trail.
• Preventative strategies should be implemented, emphasizing drinking based on thirst rather than arbitrary fluid intake.
• Educational initiatives delivered through trekking companies can mitigate the risk of EAH in this population.