From what I've read... Maximum Heart Rate is 220bpm minus your age. So for a 50 year old the max heart rate is 170bpm. Resting heart rate usually 60-100bpm. Vigorous exercise should be 85% of your max rate so 144bpm for 50year old. How easy is it to keep your heart rate at 85% during vigorous exercise like pushing up a steep hill or running? Interested in anyone experiences? Anyone a bit older who is not as fit as they should be? Does more exercise improve this value?