Will exercising on a gazelle have the same effect as jogging /running?

To a certain extent: The Gazelle will be easier on your joints but will burn less calories for a similar speed compared to running. You can increase the calories you burn on the gazelle by either increasing your "stride" rate and/or increasing resistance. In the end, using a Gazelle or jogging/running both serve to improve cardiopulmonary health. You can get similar results doing either by making small adjustments.