Sodium is an essential mineral in the body that is an important component of many processes in the body. Without it, the normal water levels in the body cannot be maintained and nerve and muscle function would be severely compromised. However, it is often portrayed in a negative light as being a major health risk and rightfully so – high sodium levels are a major contributing factor in conditions such as high blood pressure (hypertension). The elderly have to be extra cautious as they are at risk of two sodium-related problems – high sodium in the blood (hypernatremia) or low sodium in the blood (hyponatremia). Both these abnormal sodium states in the body can be harmful and seniors and their caregivers have to be prudent with regards to dietary sodium intake – not too much but not too little either. However, high sodium is not unique to the elderly whereas low sodium levels (hyponatremia) are more likely to arise with age as well as in some diseases and the use of certain medication.
Water and sodium levels are closely related regulated together. Sodium is dissolved in the body’s fluids like the blood and tissue fluid. This is controlled along with the water levels in the body fluids by increasing water intake with stimulation of thirst and regulating the water excretion through the urine. Hyponatremia may be a consequence of too much water in the body which then dilutes the sodium levels (solute dilution) but can also be due to too little sodium in the body (solute depletion). Sometimes low sodium levels may be a combination of both solute dilution and solute depletion.
With age this regulation is affected. A senior may find that their thirst mechanism is impaired and so is the kidney’s response to an important hormone known as ADH (anti diuretic hormone) which regulates the water output in the urine. These are two crucial mechanisms that regulate the sodium levels. Apart from these physiological changes with age, it may also be further exacerbated by various diseases and medication that can cause dehydration like :
The signs and symptoms of low sodium levels are non-specific meaning it is not unique to the this condition. It therefore does not clearly indicate a problem with sodium. In fact, many other diseases which are common in the elderly may have one or more of these symptoms.
In severe hyponatremia, a person can slip into a coma and respiratory arrest may even occur.
Most cases of prolonged hyponatremia in the elderly are related to medication. Therefore the medication should be changed to drugs that do not have this adverse effect on salt and water levels. It is important that the elderly or caregivers do NOT stop medication. The change in medication has to be done very carefully under the supervision of a medical doctor. Dietary intake of water and salt intake may also be modified accordingly. This should be done carefully in conjunction with a dietitian as excessive intake of salt and decreased water consumption can then lead to hypernatremia (high blood sodium) which has its own health consequences.