Rowing with a fitbit and a polar HRM

Rowed 8 sets of 500m intervals on my Concept 2 ERG with 5 min rest between sets. All out and I was THAT close to throwing up on my last set and had to back off for the last 80m.

Fit bit = basically resting calorie equivalent
Polar HRM = 469 calories.

So I'm calling rowing a low impact sport.

The fitbit adjustment to MFP takes away all but 6 calories of the rowing workout.

But I know I did it!