Heart Rate Variability (HRV): What It Is and How to Improve It

Researchers at Harvard University have gone as far as to say that measuring your Heart Rate Variability is “a visual insight into the most primitive part of your brain” which sounds great but how can us fit folks use it to our advantage?

Brock Armstrong
9-minute read
Episode #411

HRV Frequencies

I hope you are with me so far because we are about to dive deeper. HRV can get even more complex than simply assigning a high or low score.

When you are using a robust HRV tracking tool (like the one from SweetWater Health), you can also track your nervous system’s LF (low frequency) and HF (high frequency) power levels. This is important to keep an eye on for a couple of reasons:

  • Having higher power readings from LF and HF can represent a greater flexibility and a robustness in your nervous system.

  • More sedentary people have numbers in the low 100’s while fit and active people are often around 900 or higher. The numbers usually grow as fitness and nervous system health improves.

Tracking LF and HF together can truly illustrate the balance in your nervous system. Generally, you want the two scores to be relatively similar. At times when they are not, it may indicate that the body is in a rested state with too much parasympathetic nervous system activity (high HF) or in a stressed state with too much sympathetic nervous system activity (high LF).

What Impacts Heart Rate Variability?

It is commonly agreed upon that as we age, our HRV scores decrease, but there are other factors that can increase or decrease HRV in both the short & long term.

Things that decrease HRV (short-term)

  • Stress
  • Poor sleep
  • Poor diet
  • Alcohol consumption
  • Illness
  • Acute overtraining
  • Some medications

Things that decrease HRV (long-term)

  • Chronic disease or inflammation
  • Chronic stressors or burnout
  • Chronic lack of sleep
  • Lack of fitness
  • Chronic Overtraining
  • Unhealthy home or work environment

As you can probably imagine, doing the opposite of that list should result in an increase in your HRV.


All content here is for informational purposes only. This content does not replace the professional judgment of your own health provider. Please consult a licensed health professional for all individual questions and issues.

About the Author

Brock Armstrong Get-Fit Guy

Brock Armstrong was the host of the Get-Fit Guy podcast between 2017 and 2021. He is a certified AFLCA Group Fitness Leader with a designation in Portable Equipment, NCCP and CAC Triathlon Coach, and a TnT certified run coach. He is also on the board of advisors for the Primal Health Coach Institute and a guest faculty member of the Human Potential Institute.