Standard Bruce protocol for treadmill exercise test has 7 three minute stages. First stage starts at a speed of 1.7 miles per hour (mph) and a gradient of 10%. Each subsequent stage has an increment of 0.7 to 0.8 mph in speed and 2% in gradient. Modified Bruce protocol starts with a speed of 1.7 mph and a gradient of 0%. Second and third stages have the same speed, but the gradient increase by 5%. Third stage of modified Bruce protocol is thus equivalent to stage 3 of standard Bruce protocol. Further stages are just like that of subsequent stages of standard Bruce protocol. Earlier the first two stages of modified Bruce protocol were called stage 0 and stage 1/2 because the gradient was zero in the first stage and half of that of stage one in second stage