Recently I’ve been looking at different ways of visualising physiological data, and have created a Poincare plot of a funfair ride at Southport PleasureLand I sampled last year. This form of visualisation plots current and successive heartbeats as x, y coordinates, so if a subject’s heartbeat was successively 70, 80 and 75 beats per minute (bpm) we would plot (70,80) and (80, 75) on an X-Y graph. In the instance below I’m plotting heartbeat activity as inter-beat interval which is the time between beats rather than the beats per minute. I’m particularly fond of Poincare plots as its easy to grasp a subject’s heart rate variability from casual inspection. At rest a subject’s heart rate variability should be high, and so individual beats should be spread out over the graph in somewhat of a noisily fashion. When stress is applied heart rate variability decreases and beats cluster.
The Poincare plot below is of a ride, whose name sadly escapes me at the moment (and the funfairs website is down so no luck there), which involves rotating the rider at 90 degrees on all three axes. This was probably the least heart pounding of the rides I went on but I needed to warm up before the others because they quite frankly terrified me. In the plot I’ve included 2 minutes of heart beat data for pre, post and during the ride activity. The ride only lasted 2 minutes so all the data plotted is continuous data. As you can see in the plots, heart rate variability decreased during the ride by comparison to pre and post ride activity. Though even pre ride I was still pretty stressed waiting for the ride to start with minor variability increase or recovery post ride.