I could tell as soon as I started running that my energy level was low. I kept on going, though, so I could see how I felt after I had warmed up. After I reached 1.3 miles, I turned around and headed back to my car. When I got to my car, I knew I had made the right decision about reducing the length of my run. I began the run using my 3 minute running and 40 seconds walking, but as I got tired I did more walking and less running. On the way back, I probably did about 1.5 minutes each.
The temperature was in the low 50s (F), a sunny sky with beautiful clouds, and quite a few people using the Parkway. During the first part of my run, while going South, I had a 3-5 mph head wind. The wind didn't slow me down much, but it did help to keep me cool, because when I turned around and headed back, I immediately became warm and took off my wind breaker. I still wore long pants even though the temperature was in the 50s.
My wakeup heart rate this morning and also yesterday morning was 56. I haven't been recording my HR for the past several weeks because it was above 60. I was glad yesterday and today to see the HR below 60. I've been sleeping well during the past several weeks, and that contributes a lot to a lower HR.