Heart Rate Update

My heart rate was 63 at 11:20 AM this morning, but was 54 a few minutes ago. Two days ago, in the morning before doing much besides getting up and having some coffee, my heart rate was 52. I do not do “traditional cardio:” no long distance runs, no long distance bike rides, no treadmill, etc. I am getting this heart rate by doing “interval cardio” and hitting weights hard. It is interesting that I have not done much in the past six weeks or so — I’ve been taking it light and easy since I’ve been busy; I’ve gone four or five weeks without doing any sprints (“interval cardio”) or gym workouts. I’ve just messed around outside for about half hour a few times each week. I wouldn’t say the heart rate is “genetic” because it used to be in the 70s or upper 60s, from what I recall of doctor’s visits, when I was in high school. I played soccer in high school, so I was not lazy and I was not failing to get proper exercise. My siblings have a higher heart rate, I think. I’ll have to check. Maybe the carbs I ate in high school had an effect? (But then what about all the athletes who eat carbs and don’t have a heart rate in the 70s? There’s a failure to explain something by saying my rate of 70s in high school was due to carbs, I think.) Update (8-20-09, 8:15 AM CST): Yes, family members have a heart rate of 70.