A growing medical understanding shows that drinking too much water during exercise can cause life-threatening hyponatremia. This issue matters for Thailand’s athletes, outdoor workers, and festival participants in the country’s hot, tropical climate.
In Thailand’s heat, hydration matters but must be balanced. Hyponatremia occurs when blood sodium falls below 135 mmol/L. Excess water dilutes sodium, causing cells to swell and triggering dizziness, confusion, headaches, or, in severe cases, seizures or coma. The condition can mimic dehydration, making timely diagnosis challenging outside medical settings.
Real-world examples highlight the danger. A marathon trainer who drank four liters daily during training developed dangerous sodium depletion and required emergency care. An outdoor performer who consumed about four liters during a hot show suffered a seizure when sodium dropped to 117 mmol/L. These cases show that well-intentioned hydration strategies can backfire.
Public research underscores the scope of the issue. A 2024 survey found hyponatremia alongside heatstroke and heat exhaustion, signaling that sodium depletion is a meaningful risk in hot conditions. Experts warn that hyponatremia is often underdiagnosed, and its true frequency may be higher.
Certain groups face greater vulnerability. Women and individuals with smaller body frames may be more susceptible, possibly due to differences in blood volume and hormonal regulation. The hormone vasopressin rises with heat and exercise, promoting fluid retention and reducing urination, which can worsen overhydration when fluids are excessive.
Sports drinks are not a guaranteed solution. Many beverages provide modest sodium, leaving large volumes to dilute blood sodium during extended exertion. Relying on electrolyte drinks without mindful intake can still risk hyponatremia.
Diagnosis requires rapid blood testing, typically available in hospital or event medical facilities. Because symptoms overlap with heat exhaustion, field diagnosis is challenging without laboratory confirmation.
Treatment ranges from fluid restriction and dietary salt adjustments in mild cases to carefully controlled saline infusions in severe cases. In extreme situations, improper rapid correction can cause brain damage. Even home remedies require caution and professional guidance.
Thailand’s risk landscape is shaped by climate, culture, and public events. The country’s active outdoor culture, mass gatherings, and temple celebrations create conditions where heat exposure and hydration are constant. Hospitality practices and communal water sources can encourage higher-than-needed fluid intake, especially during festivals, where unlimited water is common.
Public health messaging around heat should evolve. Guidance must emphasize thirst-based drinking and appropriate sodium replacement, not simply “drink more water.” Education for healthcare workers, teachers, employers, and community volunteers is essential to recognize hyponatremia early and provide rapid care.
Practical steps for Thai audiences:
- Drink to thirst; avoid forcing large volumes of water.
- Include a small amount of salt or electrolyte solutions during prolonged activities in hot weather.
- Be alert for confusion, severe headache, seizures, or weakness during or after exertion and seek urgent medical help.
- Employers should provide access to oral rehydration solutions with electrolytes at worksites.
- Schools and sports clubs should train staff to distinguish dehydration from overhydration and ensure rapid sodium testing capability where feasible.
Thailand’s health authorities, emergency services, and community organizations can collaborate to reduce both dehydration and hyponatremia. By tailoring messaging to Thai cultural contexts and prioritizing balanced hydration, the country can protect its active population in a warming climate.