For most adults, a normal resting heart rate is 60-100. Your heart rate increases and decreases based on multiple signals. When your muscles and other organs require additional oxygen, such as during exercise, your heart will pump faster in order to provide more oxygen-rich blood. Other triggers for this include fever
, pain, and anxiety
. Most individuals will experience a range of their heart rate over any given day. However, without knowing your full medical history and whether you are experiencing any symptoms with variation in your heart rate, I cannot determine whether there is potentially an abnormal trigger for your heart rate variation, and you should seek consultation with your physician.
Given that you continue to smoke and are overweight, relatively minor activities may place increased stress on your body, and your lungs may have difficulty extracting oxygen from the air due to their smoke damage. This can cause an abnormal increase in your heart rate. Your heart can also flip into an abnormal rhythm, such as atrial fibrillation or atrial flutter, which can also cause variations in your heart rate. Finally, a blood clot in your lung (pulmonary embolism) can cause an abnormally high heart rate at rest. Although you have not listed any clear signs or symptoms that suggest an arrhythmia or pulmonary embolism, I cannot fully exonerate this without a full evaluation. Therefore, I recommend you discuss your observations regarding your heart rate with your physician. A typical evaluation consists of a full history and physical exam as well as an EKG