Athletes aren't the only people susceptible to this condition. The elderly can also be affected because of the physiological changes that come with aging. Renal function, for example, can dramatically change the metabolization of water in the body and upset the sodium balance [Source: Merck]. According to the American Academy of Family Physicians, as many as 18 percent of elderly people living in long-term care facilities are hyponatremic [source: Kugler]. Women entering menopause are also at risk of hyponatremia because of hormone fluctuation and its effect on the body's ability to regulate sodium levels.
But for the purposes of this article, we're going to concentrate on how hyponatremia occurs in otherwise healthy adults.
The milder symptoms include nausea, vomiting, and muscle cramps and spasms. The danger is that these are similar to the symptoms of dehydration, and if you misdiagnose yourself and start drinking more fluids, you'll make the problem more serious. It's very common during races for medical personnel to mistake hyponatremia for dehydration and prescribe intravenous fluids to introduce fluids into the body very quickly.
Athletes participating in high-intensity or endurance events are vulnerable to the confusion because dehydration is usually a top concern for participants. Athletes are trained to know how dehydration can not only be dangerous, but also negatively impact their performance. They're quick to pound some water or a sports drink even though they may not feel thirsty.
The symptoms can also be accompanied by headaches, lethargy and fatigue as the body fights to correct the sodium imbalance. In more serious instances, the brain swells, and confusion and dementia can set it as it presses against the skull. Brain swelling is the dangerous risk factor associated with hyponatremia because it can happen so quickly -- and escalates just as rapidly. Symptoms such as irritability and radical personality changes set in, and immediate attention is required to arrest or reverse potential brain damage. Finally, in the gravest cases of hyponatremia, the person can slip into a coma and even die as a result of pressure on the brain.
In the next section, we'll discuss exactly how hyponatremia occurs, who is at risk and how it can be identified.