I am worried so much about my heart rate. While I wake up it is around 75 to 80. After taking food and after getting ready to office it will be around 85. But while I am in office it will be varying from 95 to 105. I can not reduce it even trying to cool down (i have stressful job. I have sedentary lifestyle. Now I want want to do running in morning. But I fear because my heart rate will easily go over 150. I if start new habit of running then my heart will remain over hundred (110) whole day. I am so anxious that I keep checking heart beat every minute during office. I am so worried that I can not concentrate. I have taken 3 4 ecg. I consulted cardiologist and found no block or clot. He told my heart has no problem. After my office hours it will again reduce to 85 and before sleep it will be 75 to 80. It will reduce to 65 while sleeping. How can I stop thinking about it and develop exercise routine to lower my heart rate.