Stress Tip: Can we use heart rate variability (HRV) as a tool to measure stress levels? The oscillations of our heart are complex and are constantly changing in response to our environment. This allows for the cardiovascular system to rapidly adjust to sudden physical and psychological challenges and maintain homeostasis. Think about a time when you were really stressed— did your heart rate increase or decrease during that time? Once the perceived threat went away, did your heart rate return to normal? This is HRV, the minor subtle fluctuations in the time intervals between our heart beats that allow us to constantly remain in balance. – – In general, HRV time-domain measurements decline with decreased health. HRV has been shown to be useful in predicting morbidities from common mental disorders (such as stress, depression, PTSD and anxiety) and physical disorders (such as inflammation, chronic pain, diabetes, concussion and fatigue)— all disorders that increase sympathetic output and create a self-perpetuating cycle that produces autonomic imbalance and greater allostatic load.