Heart palpitations can be triggered by stress, exercise, medication or, rarely, a medical condition. Although heart palpitations can be worrisome, they're usually harmless. In rare cases, heart palpitations can be a symptom of a more serious heart condition, such as an irregular heartbeat (arrhythmia), that may require treatment. Symptoms.
Long-term exposure to radon can lead to lung cancer, the only cancer proven to be associated with inhaling radon. There has been a suggestion of increased risk of leukemia associated with radon exposure in adults and children; however, the evidence is not conclusive.
1 Radon is the second leading cause of lung cancer (diagram to the right) and a serious public health concern.  The primary adverse health effect associated with chronic exposure to radon is lung cancer (typically bronchogenic): -squamous cell carcinoma. -small cell carcinoma.