Fun & Fitness over 50

For my working out today, I went to the gym in the AM for a light workout. No problems there. AV HR: 94 over 50 minutes. But at lunch time, at work, I took my xc skis to the local bike path downtown which runs along the Hudson River. They plow the path but there is a nice long stretch alongside the path that I wanted to try making some practice tracks on. Actually, somebody got there ahead of me which made my job easier. Anyhow, I drove down to the path and by the time I got there my heart rate was up around 127! This is just driving the car, mind you. I expected to have an easy workout. A few days ago when I went out xc skiing for 1/2 hour, I didn't even break 100bpm. So I just shuffled around for a half hour trying to keep my rate below 120. I certainly wasn't even breathing hard. Got up to 140 at one point. My AV HR turned out to be 124 over 30 minutes. Very strange. I felt OK. Now, as I write these words at my desk, I'm down around 83bpm. Gotta keep an eye on that!