You want to lower your RHR and get fitter? This is what works for me:

• Weight loss. Lowers my RHR. My RHR won't get down near 40 or less until I'm fairly lean.

• 'Bullets'. Those are short intervals. 1 minute intervals at 300-400 watts (you try to keep the PM @ 400 but that's tough) with 1 minute rest periods, go again immediately, repeat 5x, do 2-3 sets of those. Then I do 3-4 minute hard intervals all the way home. It's the short, HARD intervals that most closely approach what you need in racing. If you can't respond to a 1-4 minute surge, you're gone. Longer intervals are necessary of course, but it's the shorter ones that give you the basic ability to hang on.

I've been doing the shorter intervals the past couple of weeks. It works. Always has in the past too. I can go from out-the-back-door to hang with the pack fitness in a couple of weeks with those workouts.

My HR is recovering from 170 to <130 in about 30 seconds much of the time, that's another sign my fitness is coming around.