best way to measure burn when trail biking?

walleymama

I've just started riding my bike on some wooded trails and forestry roads. These are hilly routes - some stretches I'm working hard but not covering much distance, others I'm flying along downhill with little effort. Just using "time spent" doesn't seem a good way to determine calories burned, but using distance via GPS isn't either due to the hilly terrain. What's my best option?

QuietBloom

Heart rate monitor by far.

matsprt1984

Absolute best most accurate way is with a power meter. Everything else is a guess.

Mr_Knight

Absolute best most accurate way is with a power meter. Everything else is a guess.

Ditto.