Push to your limit, then keep going. The anxiety you are feeling is growth.

I was fighting with the treadmill with this morning. An hour straight up a hill. Forced speed and incline will push my heart rate over 160-180. Then I ease off until it comes back to 150 beats per minute.

Tough stuff. When I felt like quitting, I pushed a little further. 1 min, 2 min, 5 min.
In the desert, it may be an hour or more. What you do in practice come out in life.

When you hit that resistance today, keep going.

Colin