Have a stress echo coming up. will working out beforehand to prepare improve test results ?

Not recommended: Depends on your cardiovascular fitness and your overall health profile. Usually you want to be tested as close to your baseline as possible because you are exercising your heart to exhaustion. It's usually not easy and you are asked to push your heart and body to the limit to see if your heart is experiencing oxygen hunger at that level. It may also give the examiner a false resting EKG and BP.