Hydration

Hydration refers to the body's balance of water and electrolytes — sodium, potassium, and related ions that allow cells to function. The term appears throughout drug references not as a general health reminder, but because several substance classes actively disrupt the mechanisms that govern this balance.

Stimulants and entactogens such as MDMA raise body temperature and increase physical activity, accelerating fluid loss through sweating. Some of the same drugs also trigger the release of antidiuretic hormone (ADH), signalling the kidneys to retain water — a mechanism that makes over-drinking as dangerous as under-drinking in certain contexts.

Alcohol acts as a diuretic, increasing urine output and reducing the body's capacity to retain fluid. Dissociatives and psychedelics can suppress the perception of thirst without meaningfully changing the body's actual need for water.

How it is done

Maintaining adequate hydration under these conditions is a matter of matching intake to output and environment, not hitting a fixed quantity. A person who is physically active and sweating heavily requires more fluid than one who is resting; electrolytes lost through sweat need to be replaced alongside water, not substituted by it.

Drinking to the sensation of thirst is generally the appropriate guide when the substance taken does not suppress thirst. When a drug raises body temperature or drives significant sweat loss, resting in a cool environment lowers the rate of fluid loss and reduces overall requirements.

Electrolyte-containing drinks or food restore the ionic balance that plain water cannot. In settings involving high ambient heat and sustained physical activity — festival environments being the common context — this distinction carries practical weight.

When it matters

Severe hyponatremia — marked by seizure, loss of consciousness, or rapidly worsening confusion — is a medical emergency. Emergency services should be contacted immediately. Fluid should not be given to someone who is unconscious or seizing.

The condition has caused fatalities in MDMA-associated contexts, almost exclusively from excessive plain water intake in hot, physically active environments. The risk is not general to all substances or all settings; it concentrates at the intersection of ADH-releasing drugs, high sweat output, and aggressive fluid replacement with water alone.

What it cannot tell you

Thirst, urine colour, and general sense of wellbeing are the informal signals most people use to gauge hydration. All three are unreliable when substance effects are active. MDMA in particular suppresses thirst while simultaneously promoting ADH release; a person may feel neither thirsty nor unwell while their blood sodium is falling.

The critical failure mode is hyponatremia — abnormally low blood sodium — which develops when large quantities of plain water are consumed without electrolyte replacement. Its early symptoms (headache, nausea, disorientation) overlap substantially with dehydration, intoxication, and heat stress. Applying the heuristic drink more water to someone already showing confusion risks worsening the underlying condition.

The reassuring result to distrust here is feeling adequately hydrated. It does not rule out electrolyte imbalance — and in substances that suppress thirst while promoting water retention, the two conditions can coexist without either making itself obvious.