Something strange happened today. When I first started riding again nine months ago from a 25 year layoff, I used the HR monitor and recorded a max of 177 consistently. (I'm an old fart, 63) Since then, I haven't used the HR monitor until today.
Same hill, same effort but no matter how hard I tried today, could not get the max HR past 166.
I've been riding regularly since nine months ago and do one weekly ride around 80-100 miles with shorter rides about 3 times a week.
What do you make of the change in the max HR?