I've been riding with the heart monitor lately, almost every day. Very educational, and I feel completely certain it's improved my cycling.
I strap it on, fire it up, go for the ride, then upload the data from the session into my PC microphone (of all things). It makes pretty graphs and charts.
During the ride itself, I check my heart rate (hr) regularly, some times tweaking my riding behavior based on the readings.
I've been getting in some very vigorous workouts. I continue the healthier diet, as well.
And I've managed to continue my weight loss. I'm down a total of over 20 lbs. now!
I've put my new Trek bike over the 300-mile mark and made my first 0ver-15-mile ride of the season already going out for a 2nd ride a few hours later (only to discover I'd somehow picked up a wobble in my wheels bad enough to encourage an abort).
The pollen counts here are killing me, though, and I'm missing a few days due to allergies. Bleh.
Got the bike into the shop to fix that wobble while I was ill. I look forward to putting it to the test, but not today. I've lost too much sleep due to the allergy problems and the meds I took to get 'em under control.