Brief Answer: In most of the times tachycardia (high heart rate) is a response to physiological situations, and there is nothing to be worried about. Yes, sinus infection may be related to tachycardia. Detailed Answer: Hello, Thank you for using HCM. I understand your concern. In most of the times tachycardia (high heart rate) is a response to physical activity, chemical interactions (like coffee or nicotine), emotional episodes, stressful situation. It can happen after eating due to lowered blood pressure or when you change immediately your position from lied down to upright position, too. In your case, the heart rate may be increased due to high physical demand during the exercises. During these situations, your body releases a series of hormones that make you hyper-alert, focused, and energized, and this chemical cascade causes increased heart rate, respiratory rate, and perspiration.The blood from the heart is pumped to aorta and subclavian arteries , and from them to the carotid arteries, which run up either side of your neck, and to your brain. This is the reason you feel your heart biting in your neck and head. Sinus infection may cause tachycardia too, due to pain or high fever, that s why it is important it to get treated. You should see the ENT doctor first, eventhough you had the tachycardia episodes prior to sinus infection. High heart rate may be either due to over function of the thyroid gland, and in this case it is accompanied with other symptoms such as sweating, tremor, anxiety, high blood pressure, weight loss etc. The symptoms, in case of hyperthyroidism are not related to physical activity , and they are present at rest too. To be quiet, you can test your thyroid hormone levels in blood (as you have a family predisposition for thyriodopathies), and after receiving the results of the laboratory exams, you should see a GP or an Internal medicine doctor. They will judge if you need to do a ECG or ECG Holter (48 hours ECG) or not. Meanwhile try not to be stressed, and avoid coffein , nicotin, etc. During this situations, you can make the carotid massage as a way to “trick” your brain into thinking your blood pressure is high, and lower your heart rate. You should make deep controlled breathing by, slow 10-second inhalation through the nose, followed by a slow and complete exhalation for 10 seconds. Hope this is helpful. Let me know if you need more clarifications. Otherwise please close and rate the answer. Kind Regards, Dr. Juarda