I m a healthy 50 year old male. I m thin,don t drink or smoke. Over the past year or so, I seem to have developed an exaggerated startle response. My limbs shake when my alarm goes off in the morning. I have these tremors in my sleep, sometimes waking me up. Is this just aging or could it be symptom of something more serious? I mentioned it to my doctor at my physical in June and he wasn t overly concerned.