I don’t know you, but when I do something, I like to track my progress. When it comes to stress, you can definitely track how you feel, but in a world of high-tech, and one where we are exposed to daily stressors from every directions, I want to be able to check often where I stand so I can better take care of it.

You can read more on stress in this article

Welcome HRV, aka Heart Rate Variability. Tracking HRV for health is nothing new, it’s been used for decades, and more recently it’s been used for sport’s performance and recovery index. But today companies have been developing algorithm to use it as an indicator of chronic stress levels.

In a nutshell: High HRV is typically a sign of general health and fitness, while low HRV can be a sign of stress or overtraining. 

What is HRV?

A healthy heartbeat contains healthy irregularities. Even if your heart beats at 60 beats per second, it does not mean it beats every second. It can beat every 0.85 sec between 2 successive beats, and then 1.35 seconds between other two. Researchers and physiologists have been tracking and utilizing HRV for decades because it is a useful indicator of several health-related issues . Lately it has gained a lot of traction for its application in the Sport industry and also Stress measurement.

Sample HRV graph from Heartmath app quickcoherence

So it is no surprise that health tech providers start using it. Garmin use it to calculate recovery times between training sessions, OURA Ring use it as part of its algorithm to score your readiness, and evaluate your quality of sleep among other signals. Heartmath technology rely on HRV to calculate your coherence rate. Finally, companies like Codesna or Moodmetric have developed a reliable methodology and technology around HRV to measure Chronic Stress. 

Want to dig a bit deeper on HRV and its effect on the ANS

Heart rate variability is a way for our body to regulate optimal blood flow to the brain. The more variation there is between the beats, the bigger the activity of the parasympathetic system. This means that the recovery functions of the body work well.

When action is needed the rest-and-digest functions of the body are shut off. Heart rate variability gets smaller for instance during the fight or flight response that activates the sympathetic nervous system. The heart pounds with regular beats. This is because in a fight the purpose is to stay alive and not fine tune bodily functions.

Aren’t there any other way to measure stress levels?

Of course there are. Apart from advance laboratory environment where doctors would use a mix of hormones test, EEG, blood pressure monitoring etc … I listed 3 other that I know of and have used before.

MEDICAL – Saliva Test

Cortisol is an important part of the Stress reaction process. 

Saliva testing is used for measuring hormones like cortisol, estrogen and testosterone, and its non-invasive collection asks patients to spit into a plastic tube. This sampling method allows patients to collect saliva at home at specific times, which is important for accurately measuring hormone levels

IN this case we look at Cortisol and DHEA hormones. Cortisol is often associated with the Stress Hormone. But Cortisol and DHEA are chemically very similar and they have a profound effect on each other. Understanding how much Cortisol and DHEA a person produces helps to identify where they are at in the Stress cycle. Higher cortisol and low DHEA means that you are probably in an advanced stage. 

I did the test one and found it useful, For some reason my levels were good in the morning and evening, but slightly higher in the afternoon and I worked with my nutritionist to adjust it (something to do with regulating my blood sugar better during the day). This was keeping me a bit on the edge.

My own Saliva test

RESEARCH survey

Some published research are based on the analysis of existing Health related surveys. In this example, the ESRI (The Economic and Social Research Institute) used the data from The European Working Conditions Surveys (EWCS) of 2010 and 2015 to produce a research for Irish policy makers. This research is interesting because the look at both :

Subjective Job Stress: The respondent is asked to estimate the stressfulness of their job, by answering All the time/most of the time/sometime/rarely/never to the question “You experience stress in your work” … this is your own perception of your stress level.

Stress Reactions: The second component of our job stress measure draws on a set of physiological stress reactions captured in the data. These are sleep disturbance, fatigue and anxiety. 

Workers are identified as experiencing job stress if they report at least one of the three stress reactions(sleep disturbance, anxiety and fatigue) and report high subjective stress (always or most of the time). This highlight the fact that you might be perceiving stress, but might not be yet showing any signs of stress reactions.

Read full research here

QUESTIONNAIRE – the old kid on the block

There are many questionnaires out there (example below). Based on how many answers you score, it estimates whether you are suffering from stress or not. Look, it is not ideal, but the reality is if you score very high, it is likely something is not right, this is how I look at it. In the example below, you only need to score 5 to be “categorized” as suffering from some level of stress, which I score every time, no matter what … And every time I ask a group to take it, majority are also over 5, so to take with a “pinch of salt”

Score 1 for every question positive answer

In Conclusion

There is no doubt that HRV is a good indicator of stress. The fact that it is easily accessible through many wearable makes it very attractive. That said, like sleep tracker, it can’t give you the whole picture. So This is how I would look at it, a good indicator which I can track. But if in doubt, I would consider additional test too.

I haven’t tested the moodmetric or codesna who claim theey can accurately detect Chronic stress. I am still to test it and read some research to make my opinion.

I am a big fan of HRV.

I personally use 2 HRV monitors. The Heartmath quicksync monitor is accurate (fix to your ear), and along with the breathing exercise, it gives me direct feedback and can create instant relief. It’s unfortunate that the HeartMath yahoos are running around spreading nonsense, because its device is simple and works, and provide a good breathing exercise base. I will write more on the heartmath as there is more than that.

I also like the HRV on my Garmin Fenix, it is a good indicator for me in terms of recovery time needed and when. After some session, my stress levels are up the roof and it is usually a good sign that I need to allow more recovery time. I personally have found monitoring HRV to be more useful than just monitoring heart rate, as a way to make sure I’m not making aerobic exercise too strenuous.

Want to read more about Moodmetric?