I was delighted to get an invite to speak at the Bay Area Quantified Self Meetup tonight. It was a great meeting and a very welcoming crowd. Here is what it looked like from an outside view as I was on stage giving the talk (Photo courtesy of Mariana Quiroga
The words and slides that I shared will come in another post. Lets instead go from the outside view to the very inside view – what was happening with my heart rate variability as I spoke. While I gave the speech I was wearing my Polar H7 which was connected to the SweetBeat Life app. After I took the readings I uploaded the data to Kubios. And to be fair to all participants, before the speech I did a session on Breathe Sync to top up my calmness.
In this graphic I show a baseline of what my RR interval, AR Spectrum and Low Frequency(LF)/High Frequency(HF) ratio looks like when I am completely relaxed. Beneath that I show progressive parts of the speech from the start point to the one-third mark:
You can see at the top on the data labelled “Smooth Sailing – baseline” the nice three peak wave in the left graphic, one clear peak in the AR Spectrum in the graphic outlined in blue and an LF of 4382 versus an HF of 454 and a ratio of LF/HF of 9.6. That is a picture of a relaxed and coherent state. Notice the difference at the beginning of giving my speech. Two peaks for RR Interval and a very pronounced HF spike (the yellow bit) and values of LF (22.4K) and HF (30.7K) that are off the charts. A huge surge of energy as I begin the speech.
As I progress into the speech my power (LF &HF) drops dramatically. I have no variability at the 17% but some variability by the 30% point. But by that point my frequency levels are as low as they are when running a 10K race. So it looks like from a frequency level that 30% into the speech I am expending as much energy as running a foot race.
Here is the graphic of the speech from the halfway point to the end:
At the 50% mark I have returned to a normal level of energy (HF is 2304, LF is 141) though my variability is low (RR interval on left). My subjective experience was that while giving the speech I felt on top of the material. At the 75% mark I have another drop in HF and LF. I recall thinking these slides where complicated so I was on my guard. As the speech reached the end point I see some return to LF levels at 1897 with one peak in the RR interval. And when I have gone through an interesting Q&A there is a huge surge of LF energy. A “rush” of completion perhaps?
I have always considered myself a capable public speaker and enjoyed giving my talks. Whenever faced with a speech I dig into it knowing I can do it. Looking at the data it could be that I have a regular cycle of stress in the beginning that ends with a huge surge of “completion” energy. When I remember the speech I remember the surge, not the stress. So I seek to do it again, ignoring the multiple less enjoyable steps that led to the surge.
Its only a hypothesis. Now you have a snapshot of a public speech at the heart rate variability level.