Hi, The most common cause of palpitations on a young man at night is anxiety. They generally start suddenly, last a few minutes and settle within half an hour. The patient may develop some chest discomfort and shortness of breath with it. Sometimes this can be aggravated by certain energy drinks or coffee, coca cola, certain drugs or alcohol. It would be better though that if this episode repeats, to see a doctor and rule out other conditions with the heart which are very rare in his age but if present they are important so it is best to be on the safe side. To conclude: - very likely these are not dangerous and are due to anxiety - still if these repeat he needs to see his doctor to rule out other more rare but important causes of palpitations as explained above. Hope I have answered your query. Let me know if I can assist you further.