I started tracking my fever with an ear thermometer, comparing that to the feeling of fever and heart rate.
Taking the temperature
I haven't measured my temperature for a long time. My fever started on the night to Wednesday, but I didn't start measuring until Wednesday afternoon. I don't know what my normal temperture is, I will continue to measure after the flu to get a baseline.
When I started measuring, I felt slightly feverish with sensitive skin, but the temperature was only 37.1 °C. Perhaps the feeling I associate with fever comes before the actual rise in temperature, or perhaps my baseline is low, but an hour later I lie freezing in bed under double covers with the fever rising up to 39.7.
Resting heart rate and fever
When my fever started, on the night to Wednesday, my heart rate went up from around 60 beats per minute to around 80. It doesn't follow the temperature, the hightened rate was about the same for 37.1 °C as for 39.7.
(Numbers on Y-axis are temperature; the heart rate would be 53 in bottom and 110 in top.)
On Thursday I had fever all day. I took ibuprofen pill for the pain, but it only lowered the fever slightly.
On Friday I again took ibuprofen, at 9:07. The chart shows the fever rapidly declining from there, but it isn't until it goes below about 37.3 that the heart rate goes down to it's normal resting rate at 54-60 by 13:30, and stays there until 15:00. The heart rate then goes up before the fever rises again!
Jumping one day ahead to Sunday, I believe I have nearer my normal body temperature of 36.6-37.3, but I'm still not sure 37.5 in the evening is fully normal yet. This chart was captured before Sunday was finished…
These charts are made with a screen dump from Fitbit's android app. I'm still waiting on the intra-day heart rate API that they should launch any week now. Then I'll be able to make real charts with heart rate data compared to other things.