Last March (2022) my mom bought me a Fitbit so I could monitor my exercise. The following data is from my Fitbit stats during the first year I had the Fitbit (14 Mar 2022 - 13 Mar 2023). When I requested the data from Fitbit, they exported a huge zip file that included all kinds of metrics like exercise, daily readiness (Fitbit's measure of how my body is prepared for exercise based on recent activity, stress levels, and sleep), and sleep data. Surprisingly, I couldn't find any data for just the number of steps I took each day, so I decided to just plot the exercise against different factors.
The "Exercise" section of this page is just my daily exercise over the year. The "Resting heartrate" section shows my resting heart rate each day, and how it stands against the amount of exercise I had. The "Sleep score" section displays my sleep score for each night, according to Fitbit, and how it measures against my exercise.
The first bit of data I wanted to plot was just the exercise itself. I try to go to the gym and use the treadmill for 30 minutes, five times a week, but that definitely wasn't a strict rule.
The tick marks on the monthly plots correspond to the days of the week, using the standard U = Sunday, M = Monday, T = Tuesday, W = Wednesday, R = Thursday, F = Friday, and S = Saturday. The month of August is particularly sparse because I was going through a lot of stress at that time and didn't feel motivated to exercise. Some of the bars throughout are really high because Fitbit took into account the times I was walking to and from campus (20 minute walk). In spring of 2022 and spring of 2023, I was teaching Tuesdays and Thursdays, while in fall of 2022, I was teaching Mondays, Wednesdays, and Fridays, so naturally those days have higher amounts of exercise.
Month:
Resting heartrate is measured in beats per minute. Some of the data is missing, I think from days when I wasn't wearing the Fitbit (I probably had it charging), and from days when Fitbit just couldn't gather the data.
When you select the data based on the month, a second y-axis appears, showing the total amount of exercise for that day, indicated by a green dot.
Month:
There seems to be a general trend that on days when I exercise more, my resting heartrate is lower. The next plot directly measures my resting heartrate as a function of exercise. You can sort of see the trend, but I think it's not as obvious because my resting heartrate for the day probably depends on exercise over the past several days. Unfortunately, I don't think I was exercising consistently enough for this trend to be more pronounced.
Each night Fitbit assigns a sleep score out of 100, based on three subcomponents: time asleep (out of 50), time in deep and REM sleep (out of 25), and restoration (out of 25, percent of heartrate below resting heartrate and percent of restlessness). Fitbit actually produces a sleep score for any session of sleep that's more than 3 hours, so on days when I took naps the average is taken between the nap and that night's sleep.
Month:
It seems like my sleep score is higher on days when I exercise, as long as it's not too much exercise. In the following plot, you can see that my sleep score varies a lot when I have a moderate amount of exercise (20-40 minutes per day). But when I have a lot of exercise it's on the higher side.
I think this data only gives a snapshot of how my overall health is affected by daily exercise. The scatterplots in particular might show a more pronounced trend if given more data. However, it seems like even just a moderate amount of exercise, when done consistently, has a positive impact on my overall health.
There are many directions in which to go with just this data. For one thing, I would like to have a snapshot of each day's data when you click on the bar in the graph. Also, if I remember correctly, I'm less likely to exercise on Mondays, after the weekend, so it could be useful to see my average amount of exercise for a given day of the week. I would also like to see the breakdown of my sleep scores based on the subcomponents. It seems like more exercise would lead to a longer period of the restorative deep and REM sleep, and I would like to see that verified in a plot. Finally, Fitbit keeps track of exercise according to heartrate zones: fat burn, cardio, and peak. Exercise from running on the treadmill is more intense than exercise from walking to work, and those minutes in the cardio and peak zones must also play a role in determining my resting heartrate and sleep score.