I think it's a great idea. You might inspire me to try it. I exercise, but I've never tried something like this.

But, it's not a complete program. First, your yoga and 40 minutes of cardio are a great practice that should not be given up.

If you do this, and why not, try to add some exercises to balance the work. Your kayaking and canoeing is going to help balance some of the work, because they should both be working your trapezius and rhomboid muscles. Many of the exercises that work these muscles are called rows, because that is the motion they use, pulling the resistance into your body by using the muscles in your upper back. If you added some pull-ups you'd have the makings of a darn good routine. If you cannot do more than one or two pullups, you could try to do some on angles and do some pulldowns, with some rubber bands if not weight.