does it meen you are fitter if you have a low heart rate and- is the limit on how much you can lower it genetic (which would explain you there are a few world level athletes) can you improve it by exercise, specifically boxing
What Virus said, there are so many factors and different types of 'fitness'. Low heart rate can also be an indicator of heart problems.
In general it reflects a higher level of cardiovascular fitness/endurance. But if you've got a low heartrate and don't train hard or at all, might want to get that checked out. It's one of those things that you develop through training hard for a long time, or just have naturally because you have heart problems.
Last I checked it was 55, but I haven't been training at all. When I was in full swing (but sick) it would be 42ish. Even that low worried a few doctors until they found out I played soccer. Had a Navy doc tell me after he took it twice that "there's no way that's right or you'd be dead." Your tax dollars at work, ladies and gentlemen.
Place your index fingers (2 first fingers) just underneath your jaw to the left or right, wait for the first few beats then find the clock and when the 1 minute starts you start counting