Based on FDA | Does taking sertraline increase the risk of hyponatremia during prolonged or intense exercise?

Taking sertraline can increase the risk of hyponatremia (low blood sodium), and prolonged or intense exercise can add additional stress that may further lower sodium in certain situations. ^[1] During exercise, especially endurance events, drinking excessive plain water without enough electrolytes can dilute blood sodium, and this risk may be higher if a medicine like sertraline is already predisposing you to sodium loss through a mechanism called SIADH (syndrome of inappropriate antidiuretic hormone secretion). ^{[1] [2]}

What we know about sertraline and hyponatremia

• Sertraline and other SSRIs have been associated with clinically significant hyponatremia, often due to SIADH; this has been reported across the SSRI/SNRI class. ^[1] Hyponatremia can be severe and is reported more often in older adults and in people who are volume depleted or taking diuretics. ^[1]
• Common warning signs include headache, confusion, difficulty concentrating, weakness, nausea, and unsteadiness; severe cases can cause seizures. ^[1]

Why exercise can add risk

• Endurance or high-intensity exercise can lead to significant sweat losses of both water and salt; replacing the loss with large amounts of plain water can dilute blood sodium (exercise‑associated hyponatremia). ^[2] Athletes are advised to drink to thirst and aim to replace fluid roughly in line with sweat loss, not more. ^[2]
• When an SSRI like sertraline is on board, the body may be more prone to retaining water via SIADH, which can combine with high fluid intake during prolonged exercise to lower sodium further. ^{[1] [2]}

Who is more vulnerable

• Individuals older than 60–65 years appear to have a higher baseline risk of SSRI‑related hyponatremia. ^[1]
• People with low body weight, a prior history of hyponatremia, use of diuretics, or medical conditions that affect fluid/salt balance may also have increased susceptibility. ^[1]

Practical precautions for training and events

• Drink to thirst rather than on a fixed schedule, and avoid overdrinking plain water during long workouts or races. ^[2]
• For endurance sessions, consider using fluids that contain electrolytes (sodium) to help replace what is lost in sweat, especially in hot conditions or if you are a “salty sweater.” ^[2]
• Be alert for early symptoms of low sodium (headache, nausea, confusion, unusual fatigue, muscle cramps), and stop activity and seek medical evaluation if these occur. ^[1]
• Talk with your clinician about checking blood sodium (serum sodium) after starting or increasing sertraline, particularly in the first weeks and if you do endurance training; older adults and those with risk factors may benefit from periodic monitoring. ^[1]

When to seek urgent care

• If you experience severe confusion, vomiting, seizures, or profound weakness during or after prolonged exercise, seek emergency care, as these can be signs of acute hyponatremia. ^[1]

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Quick reference table

Factor	How it affects sodium	What to do
Sertraline (SSRI)	May increase ADH effect (SIADH), promoting water retention and dilution of sodium	Monitor sodium when starting or adjusting dose; watch for symptoms; discuss risks with your clinician
Prolonged/intense exercise	Sweat loses water and salt; overdrinking plain water can dilute sodium	Drink to thirst; aim to match fluid to sweat loss; avoid overdrinking
Hot environments, long durations	Higher sweat losses increase dilution risk if fluids are hypotonic (plain water)	Include electrolytes (sodium) during endurance efforts
Older age/diuretics/low body weight/history of hyponatremia	Increases hyponatremia vulnerability with SSRIs	Consider baseline and follow-up sodium checks; individualize hydration plan

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Bottom line

Sertraline can raise the risk of hyponatremia, and prolonged or intense exercise especially with high water intake and low electrolyte replacement can add to that risk. ^{[1] [2]} With sensible hydration (drink to thirst, include electrolytes for long efforts), awareness of symptoms, and, when appropriate, periodic sodium monitoring, most people can exercise safely while taking sertraline. ^{[1] [2]}