The present inventions, in one aspect, are directed to a portable monitoring device to calculate calorie burn of a user, comprising a motion sensor to detect motion of the user and, in response, to generate data which is representative of motion of the user, and an altitude sensor to detect a change in altitude of the user and, in response, to generate data which is representative of the change in altitude of the user. The portable monitoring device may include processing circuitry to: calculate data which is representative of a change in elevation of the user using (i) the data which is representative of motion of the user and (ii) the data which is representative of a change in altitude of the user, calculate first calorie burn using the data which is representative of motion of the user, and calculate second calorie burn by adjusting the first calorie burn based on data which is representative of a change in elevation of the user. The portable monitoring device may include a housing having a physical size and shape that is adapted to couple to the body of the user.
