Originally Posted by

**CdCf**
The cheaper method is to find a long and fairly steep hill. It has to be steep enough to bring down speeds far enough to simplify aerodynamic considerations, but long enough to allow your HR and speed to stabilise early on during the climb.

Get on your lowest geared bike, strap on your HRM and ride up the hill at different speeds and record your average HR for each ride. Repeat several times for each speed.

Then measure the distance of the climb, and use a spirit level and a ruler to measure the grade of the hill. The total weight of yourself and the bike (including clothes, shoes, water bottle(s) and so on) and a certain amount of air resistance determines the power exerted during the climb at any given speed. The calculations aren't very complicated, but I won't go into it in this post.

Anyway, once the power has been determined for each climbing speed, it's possible to correlate each power level to an average HR. With enough data points, a HR vs power curve can be created.

If this has been done once, the relevant stuff can be entered into an Excel spreadsheet. If a new power/HR curve needs to be created, you'd only have to repeat the climbs and enter the new data into the sheet.

It all sounds tedious and like it's a lot of work, but it doesn't have to take more than a couple of hours the first time, and maybe half an hour for each subsequent test.

The whole point is to find how power relates to HR for an individual. This will change over time, and from day to day to some extent, but it provides a good indication of power levels during any ride.