I have been doing quite moderate/intense cardio for the past 25+ years.  I am a 52 year old male.  When I go to the gym and hold onto the handle for a heart rate (without working out) it says 88 or 90.  When I run for say 20 minutes (10 minute mile) it goes upto 140.  Does this sound right?
Hello sires that's perfectly normal and physiological. Heart increases to meet the increased oxygen demand of the muscles during workout by supplying more amount of blood. You are going great just keep it up. Wish you Good Health. Do let me know if you are satisfied with my answer in the reviews in my profile. Thanks