eng Science and Education Publishing Journal of Physical Activity Research 2574-4437 2023-09-12 8 1 52 55 10.12691/jpar-8-1-9 JPAR2023819 article John Hart DC MHSc jhartec@yahoo.com 1 Hart Chiropractic, Greenville, South Carolina Exercise often improves health status as evidenced by improvements in physiological measures such as heart rate variability. With modern technology, such as heart rate apps for smartphones, an individual can track his or her own data on a daily basis. They may also go a step further and enter their data into a spreadsheet for further analysis. In this way they can study their own data, e.g., when a change in training occurs, to see if there is a benefit following the change. The present case study provides an example of how the approach can be used. http://pubs.sciepub.com/jpar/8/1/9/jpar-8-1-9.pdf Exercise heart rate variability self-measurement health