Hyponatremia
Hyponatremia is a lower than normal amount of sodium (also known as Natrium, the source of the chemical symbol Na for sodium) causing the cells in the body to swell due to osmotic pressure. Sodium is also needed for the proper function of muscles and nerves, which is why headaches, muscle cramps, and fatigue is associated with heat injuries.
A modern form of college hazing involves forcing a pledge to drink several gallons of water in a short period of time leading to hyponatremia, which has symptoms similar to being drunk. The excess water dilutes the normal concentration of electrolytes and the constant urination removes them, causing further imbalance in the body. This is a life-threatening condition that needs medical treatment just as much as the alcohol poisoning that it replaced.
Drinking plain water while working in the heat can cause the same imbalance because the salt lost through sweating is not being replaced. Sodium, and to a lesser extent potassium, need to be replaced in order to treat or prevent the symptoms of heat exhaustion.
Fruits and vegetables are also a good way to replace water and electrolytes, since most of them are 75%+ water by weight, and the fructose (fruit sugar) helps by giving a little energy boost along with the water content. Watermelon is a favorite around here, but plums and apples work well; citrus fruits are more common further south and provide a Vitamin C boost as well. Canned vegetable juices like V8 are a also good choice, if you like the taste.
Replacing lost salt is almost as easy. Salt is a (too-)common preservative used in preparing food, and the normal American diet contains plenty. There are various sport drinks like Gatorade that will provide the electrolytes you need in a variety of forms. I buy mine when they go on sale, and keep a few cases (usually quart bottles) in the basement for use through the summer, but the powder form is handy for storage and comes in sizes from individual packets for mixing up a pint to industrial-sized bags that will make gallons. Working in a group, in the heat, I prefer a 3-gallon cooler full of iced Gatorade with a supply of paper cups.
A modern form of college hazing involves forcing a pledge to drink several gallons of water in a short period of time leading to hyponatremia, which has symptoms similar to being drunk. The excess water dilutes the normal concentration of electrolytes and the constant urination removes them, causing further imbalance in the body. This is a life-threatening condition that needs medical treatment just as much as the alcohol poisoning that it replaced.
Drinking plain water while working in the heat can cause the same imbalance because the salt lost through sweating is not being replaced. Sodium, and to a lesser extent potassium, need to be replaced in order to treat or prevent the symptoms of heat exhaustion.
Hypernatremia
Consuming too much salt, or not enough
water, leads to an increase in electrolytes, which causes the cells of
the body to shrink and leads to brain damage and irregular heart rate.* Losing water through sweating can reach the point
where blood volume is lowered and blood pressure will drop, leading
to the symptoms of heat stroke. This is known as hypernatremia.
Replacing water lost through sweating
is fairly easy: drink until you have to urinate, and keep drinking water
until your urine is light yellow in color.See the chart to the right for examples.
Fruits and vegetables are also a good way to replace water and electrolytes, since most of them are 75%+ water by weight, and the fructose (fruit sugar) helps by giving a little energy boost along with the water content. Watermelon is a favorite around here, but plums and apples work well; citrus fruits are more common further south and provide a Vitamin C boost as well. Canned vegetable juices like V8 are a also good choice, if you like the taste.
Replacing lost salt is almost as easy. Salt is a (too-)common preservative used in preparing food, and the normal American diet contains plenty. There are various sport drinks like Gatorade that will provide the electrolytes you need in a variety of forms. I buy mine when they go on sale, and keep a few cases (usually quart bottles) in the basement for use through the summer, but the powder form is handy for storage and comes in sizes from individual packets for mixing up a pint to industrial-sized bags that will make gallons. Working in a group, in the heat, I prefer a 3-gallon cooler full of iced Gatorade with a supply of paper cups.
For those of you who like to DIY, there
are lots of recipes out there:
- The military used to suggest a mix of ¼ teaspoon salt + ¼ teaspoon baking soda added to a quart of water, but has switched to prepackaged drink mixes.
- WebMD and several international websites suggests ½ teaspoon of table salt + 6 teaspoons sugar in a quart (or liter) of water for ages 12 and up, but don't have a specific recipe for children. Children need a more dilute mixture because their bodies are still developing the mechanisms for dealing with heat. Oneof the sites recommended adding ¼ teaspoon of salt substitute (potassium chloride) as a source of potassium, which makes sense.
Prevention is Part of Preparation
This summer seems to be start a bit
early around here and I've seen some record high temperatures in
other parts of the country as well. Stay hydrated and keep your salts
in balance; you're not going to be doing anything useful if you are
lying on the ground with cramps and nausea, or are being transported to
the hospital.
* This is acute (short-term) salt intake, not the commonly derided high sodium diet common in America that has ties to high blood pressure and heart disease.
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