As an electrolyte, sodium conducts electricity whenever it is dissolved in water. It participates in such important processes that every cell in your body needs it to function properly. Along with chloride, it is naturally more abundant in your blood and bodily fluids than inside your body's cells.. Sodium's importance for proper heart function is such that imbalances can raise or lower your heart rate.
Sodium's Roles inYour Body
In "Reversing Hypertension," California-based physician Julian Whitaker stresses the critical role sodium plays in the regulation of your blood volume, water balance and blood pressure. Sodium also aids digestion by helping your body to produce hydrocholoric acid, and facilitates the absorption of chloride, amino acids, glucose and water. More importantly, sodium is a key component of the energy system in all your cells because it provides them with the electrical charge they require to function optimally. This is particularly important for your nerve and muscle cells, including heart muscle cells.
Sodium Levels
Blood sodium levels normally range from 135 to 145 milli-equivalents per liter, or mEq/L. According to National Institutes of Health-affiliated physician Anthony Fauci, a value below 135 mEq/L reflects hyponatremia, or low blood sodium. Hyponatremia is considered severe when blood sodium falls below 125 mEq/L. In contrast, values above 145 mEq/L define hypernatremia, or excess blood sodium.
Heart Rate and Blood Volume Control
For an adult, a resting heart rate normally ranges from 60 to 100 beats per minute, or bpm. However, if you are a well-trained athlete, a resting heart rate of 40 to 60 bpm would be normal. Your heart continuously works like a double suction and pressure pump to maintain a steady flow of blood to all your organs. Adequate blood flow is so important that your cardiovascular system constantly tries to adjust to any electrolyte or fluid voume changes it detects, according to "Reversing Hypertension."
Effects of Excess Blood Sodium
Whenever sensors in your heart, blood vessels and kidneys detect high blood sodium levels, your body increases its rate of sodium excretion, and pulls water out of your cells an attempt to maintain adequate adequate sodium concentrations. According to the Merck Manual, hypernatremia usually results from dehydration. The effect is an accelerated heart rate, or tachycardia. However, severe hypernatremia can also raise your blood pressure, and cause breathing difficulties, convulsions, coma or even death.
Effects of Low Blood Sodium
The Merck Manual attributes hyponatremia to various causes, including: cirrhosis, heart failure, excessive vomiting or diarrhea. In such cases, whether the fluid volume is normal, elevated or low, the main problem is that sodium is too diluted. Low blood sodium causes your body to hold on to its remaining sodium, thereby increasing blood volume. Your heart rate initially increases as a result, but advanced hyponatremia causes bradycardia, or slower-than-normal heart rate. Low blood sodium can also impair your brain function and lead to hypotension, or low blood pressure.
Considerations
Your brain is particularly sensitive to changes in blood sodium levels, according to the Merck Manual. You are therefore likely to experience nervous symptoms, such as sluggishness and confusion, before muscle dysfunctions manifest. Your heart is a muscle, and sodium imbalances usually need to be severe to cause abnormal heart rates. The Merck Manual indicates that fast-changing sodium levels and advanced age usually increase both the rapidity and severity of your symptoms.
References
- "Reversing Hypertension;" Julian Whitaker, M.D.; 2000
- Linus Pauling Institute: Salt Physiology
- Merck Manual of Medical Information: Sodium
- "Harrison's Principles of Internal Medicine 17e”; Anthony Fauci, M.D. et al; 2008
Member Comments