Resting Pulse

I have been tracking my resting pulse/heart rate since I have started my weight loss journey. I have now lost 168 pounds in the past 13 months. When I started, I had a resting pulse of 85-95. Now, I have a resting heart rate of 50. I have been lifting weights, swimming, and walking for exercise. I have read that swimmers and endurance athletes often have low resting heart rates. I swim every weekday for 30-60 minutes and I exercise now about 2-3 hours a day six days a week. I'm 38 years old. To me, this is another good indicator of my health and fitness level. Any thoughts on resting heart rates?