Note that because Strava only recorded 42 km, it failed to register that I had run a marathon, how cruel! Also, 4 hr 23 min is the time with stops excluded, compared to 4 hr 34 min as our official finish time.
The heart rate graph on the left comes from chest strap and shows that heart rate stayed pretty constant throughout the marathon. There’s even a slight reduction when course starts to become easier at the 70% mark.
The graph on the right has the heart rate as measured by Fitbit Charge HR in addition in green. The average on fitbit is 10 bpm higher (151 instead of 141) and it’s interesting to see how it appears to over-estimate heart rate when we go strong downhill. We can probably expect more arm movement then and it may affect the measurement.