During my run last night, I was having a lot of trouble keeping my HR in the proper zone. In fact, by halfway through the workout, I gave up on the HR monitor and turned off the warning beep. After the workout I noticed that since my BD was yesterday, it automatically updated my MHR to 187, which is what is predicted by my age. That got me thinking, what is my actualy MHR? I had previously set my watch to 194 as my max, since it has actually been that high during a workout when I did an all out sprint at the end. I've been doing checking around to try to figure a way to calculate it but everything I've found has me somewhere between 184-189. I really want to get this right, but am not sure what to do. I do know that my resting rate is between 40-43 and my sitting is between 57-60. Any suggestions for what to do about my max?