When I finally got serious about 'getting fit', I bought my first Oura ring. At the time, I primarily wanted to fix my sleep issues. A happy side effect of this purchase was that it made me more aware of my Heart Rate Variability (HRV). I always considered my HRV on the lower side, but quickly realized that I felt my best when it was at the higher end of the range. Pretty much since this realization, I've been experimenting with various ways of raising my HRV. Many ways of raising HRV involve...