Thanks for adding me to the group, Alan. For a while now I've been skeptical of the general consensus that max HR, VO2max decline linearly with age and of chosing outliers as examples ("Look at Fred. Fred is 94 and still cycling 200miles/ week"). Surely they've filtered the data before performing their analysis. I.e. they study a group of masters athletes, omitting those that no longer training/compete because they lost interest/ fell ill/ picked up an injury. So I was very interested to see Simon Willis, in the video I've linked below, refer to studies that show aging takes place in steps (at the ages* Alan mentions above). This channel actually has a lot of good topics for the "aging athlete". (Of particular interest to me are the interviews with a cardiologist from the hospital in Inverness. I feel the advice from a cardiologist who has atrial fibrillation himself is probably going to be reliable.) * There are other studies that present step changes at different ages. My learning is work in progress. https://youtu.be/GFJXavNOOeM?is=Nd6HwqVusn15kkuN

@Duncan Martin I think you can feel it at the time but it's more obvious in retrospect.