Hi Phil, don't stress too much 
which heart rate monitor are you using?
I would really like to tap into your zones. One good thing and which should be good news for you, is that your running level is actually quite high for the lower vo2max max of 47 - 49. This definitely coincides with my thoughts on the runner and the aerobic capacity dropping as we get older.
It is going to be great to see how performances improve once the vo2max goes over 50
please let me know how you recover from today's run and then we can look to put something out on Wednesday
TheEd
which heart rate monitor are you using?
I would really like to tap into your zones. One good thing and which should be good news for you, is that your running level is actually quite high for the lower vo2max max of 47 - 49. This definitely coincides with my thoughts on the runner and the aerobic capacity dropping as we get older.
It is going to be great to see how performances improve once the vo2max goes over 50
please let me know how you recover from today's run and then we can look to put something out on Wednesday
TheEd