Apple Watch Outdoor Cycling

I have been using the fitness app to track my outdoor cycling exercises for the past month fairly regularly. I’ve recorded work outs as long as 2 hours with an average heart rate of 165, and my burned calories will be less than 500. Any other calculator online I go to shows twice as many burned for the same heart rate vs time. Apple can you address this in some way. I’m getting killed in competitions against my friends who work out half the time with less strenuous exercise because they chose a different “workout” on their watch.