Do you use HRV (heart rate variability) to monitor client/athlete stress, fatigue and even burnout?

Heart rate variability (usually known as HRV) is a relatively new method for assessing the effects of stress on your body. It is measured as the time gap between your heart beats that varies as you breathe in and out. Research evidence increasingly links high HRV to good health and a high level of fitness, whilst decreased HRV is linked to stress, fatigue and even burnout.