My HR Zones reset upwards overnight, and now require me to exceed (220-age) while still in Zone 4. Older activity still shows normal zones so no longer comparable. I didn't change any settings. What's happened? Is this correct?
My HR Zones reset upwards overnight, and now require me to exceed (220-age) while still in Zone 4. Older activity still shows normal zones so no longer comparable. I didn't change any settings. What's happened? Is this correct?