A resting heart beat of 20 is absolute nonesense. I was a professional cyclist a long time ago and represented my country (GB) several times.i took my heart rate every morning prior to getting up and if was 35 - 40 beats per minute.(aged 19 at the time)My heart rate never exceeded 185. Seeing how high you can raise your heart rate is not a measure of fitness. Fitness is measured ( by competitive results in the first place)by your recovery rate. This can be completed by interval training. i recall during my training that from 180 BPM down to less than 120BPM would take approximately 25 secs.