Using METS to compare workout intensity

To compare one workout to another, try using the METS feature on your elliptical machine or stationary bike.   METS refer to the Metabolic Units associated with your current energy expenditure level.  As you become more fit, your attainable MET level will increase.  You may be in the same program in terms of resistance, but you are striding faster or increasing your RPM on a bike.  The MET level will show this increase in your exercise intensity.  It will also let you know which types of workout are most intense.