Can lack of exercise cause higher heart rate ? I am 21, eat healthy ( no fast food, lots of fruit an vegetables, usually drink just water ), am stil a student, but i m very lazy and don t move at all, but i m stil very skinny. I don t smoke nor drink exces amounts of alcohol and i don t drink a lot of coffe ( 1 cup a day ). Someties i experience my heart rate to rise, especially in the evening. When i don t sleep enough, my heart rate goes through the roof.