I figured out that I had just gone past the site of yesterday's near miss, and the elevated heart rate had nothing to do with exercise and everything to do with nerves, terror or just plain fear. Even though the brain felt no fear, the body did. Quite a wierd sensation.
Riding in the early hours is usually the safest time for me - the traffic has not built up to a state where half the motorists on the road are going mental in gridlock, and the distracted mums doing the school run are still at home wiping egg off the chins of their sprogs. The streets are generally free of rat runners as well, as there is no need to rat run as all the roads are empty of cars. Close calls like yesterday are good motivation to drag myself out of bed early, and to avoid getting bogged down in reading too many blogs before hitting the road.