Elizabeth M. Ferraro, ATC and Megan A. Barry, ATC
Hyponatremia is a low concentration of sodium in the blood. When it occurs during exercise, it is called exertional hyponatremia. It is mostly seen in athletes, although it can occur to anyone who either consumes more fluid than necessary in a short time or when too much sodium is lost through sweat and not replaced. Hyponatremia doesn’t always occur during exercise. It can occur hours later if sodium lost is not made up after.
- Have a hydration plan in place
- Record body weight before and after exercise to monitor fluid consumption
- Know the sweat rate to determine fluid consumption during exercise
- Know the signs and symptoms of hyponatremia
- Have an emergency plan in place for dealing with hyponatremia
- Monitor the duration and intensity of exercise for determining risk of hyponatremia
- Educate athletes of risks from fluid overload and encourage moderate hydration.
- Establish individualized hydration protocol based on personal sweat rate and sports dynamic.
- Consume adequate dietary sodium.
- Allow 8-14 days of training in the heat for acclimatization.
- Identify pre-exercise hyponatremia by recording body weight each day
- Altered mental status, disorientation, combative behavior
- Swelling in extremities, bloating
- Muscular disturbances
- Identify over-hydrated athletes or athletes who limit sodium intake.
- Onset of symptoms
- Assess blood Na+ using portable blood sodium analyzer (<130mmol/L)
- Inquiry fluid and food consumed and use of NSAIDs
- Record vitals
- Exertional Heat Stroke
- Heat Exhaustion
- Heat Cramps
- Cardiac Condition
- Consume oral hypertonic saline (e.g. bouillon) or hypertonic saline IV
- Consume salty foods such as potato chips, pickles, jerky, or bullion
- DO NOT provide normal saline solution or fluids
- Transport to hospital for blood work if symptoms worsen
Return to Play
- Require a physician clearance
- Measure sweat rate and Na+ concentrations
- Gradually increase exercise intensity and duration per environmental conditions
Recommended Equipment List
- Hypertonic saline
- IV equipment
- Portable blood Na+ analyzer kit
- Salty foods (e.g. bouillon cubes, pretzels, canned soup, and potato chips)
- Rectal thermometer
- Blood pressure cuff
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