Unfortunately, if you are looking for a sport that will give you the best chance of getting into shape, it isn’t scuba diving.
We aim to move slowly and be as relaxed as possible with minimal stress on our bodies. This gives us the best chance of having a longer dive as we use less air this way. We also increase the amount of nitrogen we absorb into our blood when we swim quickly and aren’t neutrally buoyant. This nitrogen is the cause of the dreaded decompression sickness.
Basically, the more experienced you are and the more you improve as a diver, the less you need to exert yourself when diving. This means you will usually burn fewer calories as you progress as a scuba diver.
It’s important to note that the number of calories burned during a scuba dive will vary depending on these factors and individual circumstances.
If you want to get in shape, then it’s a good idea to add strength training and start combining cardio to your routine, but I’d recommend not doing it close to any scuba diving you have scheduled, it’s key to leave hours between activities.