Hello. Welcome to HCM, thank you for your question. I understand your concern. These episodes occur when you are asleep and they wake you up, as you described. Then, I assume, the fear of is something wrong with me? takes over. Sleep has two phases, on of which is the phase with highest brain activity during sleep and the particular phase when we experience dreams or nightmares. It is called the REM (rapid eye movement) phase. It is characterized by rapid heart rate, shortness of breath and, sometimes, high blood pressure. All these are attributed to high secretion of adrenalin and noradrenalin, a characteristic of this phase of sleep. My opinion is that no further investigation or treatment is needed, and that you should not worry about it. I hope I was helpful with my answer. Kind regards. Dr. Meriton