> different picture for athletes Calories burned depend on many factors, so they are basically impossible to predict without knowing at least age/weight/height

> different picture for athletes Calories burned depend on many factors, so they are basically impossible to predict without knowing at least age/weight/height and more ideally the accurate heartrate during the workout of the person. But nonetheless I'd say that if you are able to perform a single session workout in which you burn >= 1000, I think you deserve the label "athlete" and do not count as a beginner.