While a slight drop in an individual's potassium level does not usually result in visible signs or symptoms, a significant drop can slow down an individual's heartbeat and lead to feeling lightheaded or fainting, according to MedlinePlus. When a person's potassium level drops too low, it can eventually stop his heart from functioning. Other effects of a low potassium level include numbness and palpitations.
People who have low potassium levels sometimes experience fatigue, muscle cramps, constipation and weakness, explains Mayo Clinic. Low potassium levels are often due to an illness or the intake of diuretics. While diuretics primarily treat hypertension, some forms of the drug can cause an excessive excretion of potassium through urine. When an individual suffers from extremely low potassium levels, the most serious complication is arrythmia, or an abnormal heart rhythm, especially when it occurs in people with existing heart disease.
When the potassium levels in a person's blood are too low, it can result in a condition called hypokalemia, according to Healthline. Potassium is a vital electrolyte that keeps the body's muscle and nerve cells functioning properly. This disorder is usually a result of losing too much potassium through excessive sweating, bowel movements or urine. Side effects and complications of hypokalemia include vomiting, nausea, extreme thirst, low blood pressure and loss of muscle control.