Hello. Thank you for your question and welcome to HCM. I understand your concern. I can see this has come as a concerning and worrisome phenomenon to you. I will start by saying that we have a formula for the heart rate achieved during exercise or psychological stress, which is considered normal. It is 220-age, which means, during physical activity, heart rate up to 178 beats per minute (in your case) is considered normal. In fact, heart rate not going up during exercise (not necessary up to 178 beats per minute) is considered abnormal. If I were your doctor, just to be in the clear , I would also recommend you to perform EKG, echocardiogram and 24-hour rhythm monitoring. But, I can see they all came back normal, as expected. Therefore, my opinion is that you have nothing to worry about, even encourage you to continue with the physical activity (walking, brisk walking, jogging, gym, swimming, biking etc.) and recognize it as a beneficial lifestyle habit, with great benefits on physical and mental health. I hope I have been of help. Take care. Best regards, Dr. Meriton