Cardio (Tacx/Strada) 55:56 27.63 km (2:01 / km) ahr:129 max:141 shoes: D2 2D action blue road
140 watt spin, varying resistance every 10 minutes.
This seems to be the power level that keeps my heart rate in its endurance space. Cadence much below 70 is very hard to keep the power down. Cadence over 85 tends to ramp up the heart rate. That might be all I need to know for a 12 hour.