Math

I want to creat a easy-to-use formula to measure the intensity of a exercise workout. The input factors are: 1. Minutes exercise. 2. Miles run. 3. Calories burned. 4. Level of treadmill. So, if: Minutes = 50 Miles = 4 Calories = 423 Level = 10 Therefore, what is the overall intensity of the workout using these four numbers? Thank you for your help. Stuart