In the last month or so I've noticed that when I get in to bed and settle down to sleep I become aware that my heart is thumping. I don't experience any anxiety, etc so it's not that. It is not a hyper awareness thing either my heart is literally thumping. It slowly settles down and I go to sleep. If I wake up I don't experience it unless I move around a lot because of overheating and then I feel it a bit but not the real thumping. I'm on 125mcg thyroxine ( have been on meds for 4 years) and tsh is under 1. Havnt had t4 or t3 measured for ages as my GP won't do it. I don't have any hyper symptoms. I'm 49.