I wonder if an AR device that only renders stationary floating text could be produced with much lower GPU (and thus power) requirements than the current crop of

I wonder if an AR device that only renders stationary floating text could be produced with much lower GPU (and thus power) requirements than the current crop of headsets. What I want is a computer + headset that can be fully powered by moderate exercise. From what I've read, manual labor averages about 75 watts of mechanical power throughout the work day, so with conversion losses, maybe 20 watts produced by pedaling or rowing action. Then I could "sit at the desk" all day without wasting away, and do it from the middle of a forest or the top of a mountain if I wanted to.