HEART RATE VARIABILITY

What is it, how does it represent health, good HRV number, how to instantly improve HRV & how to track HRV - Explained in detail

HRV is THE buzzword in health these days and rightly so, as it may quite possibly be the most important Health metric.

While we may track health metrics like Calories, Steps, weight and whatnot, the simple matter of fact is that HRV trumps them all when it comes to representing actual health as HRV actually tells you how your body is feeling.

Say you’ve been following a certain workout and a diet regime, how would you know its immediate and long term impact on the body?

Did it just increase/decrease your muscle mass or did it actually make your health better?

Such lifestyle/habit changes questions can be answered with HRV.

WHAT IS HRV

Not to be confused with heart rate, HRV is the interval between successive heart beats.

A heart does not beat at the same speed constantly, it keeps on varying, and those variations are known as HRV. By analyzing those variations, a lot of information about health can be uncovered and is the essence of HRV analysis.

NERVOUS SYSTEM & HRV

When we are stressed, the heart tends to beat faster and vice versa, when we are relaxed, it tends to beat slower. An increase in HRV is also observed with relaxation.

When stressed, the nervous system prepares the entire body system to focus on a narrow region of interest (flight or fight response) which immediately reduces HRV as most resources are no longer available for other body/mind processes.

Similarly, when relaxed, more resources are freed up which register an increase in HRV.

In fact, HRV is very sensitive to even the minutest change in physical, emotional or mental state/activities.

The idea is to build up your overall HRV in the long run, as we’ll discuss later.

HOW IS HRV A SIGN OF HEALTH & FITNESS?

HRV generally signifies Body’s load taking capacity.

High HRV generally means optimum working of the nervous system and that the body is able to adapt to varied situations.

If you’re fatigued, HRV will invariably be low. It means your Heart is receiving the signal to work even harder to repair and regenerate your body.

Quite naturally, hard tasks will be harder to do, a good example would be a foggy mind unwilling to work on anything, chances are your HRV would be lower than your usual baseline.

There are times when low HRV is not a bad thing like when working out, as the body will allocate more resources to the workout. However, how quickly your HRV bounces back to its usual range shows how fast your recovery was.

During sustained days of strenuous effort like say a Cycling tournament, HRV may stay low, but should be able to bounce back later.

Now, if you’re not being active or not recovering from something, but still your HRV is low, it means you’re fatigued for some reason and need to focus on recovery.

GOOD HRV NUMBER

Our data shown below shows the Median HRV (SDNN) with respect to user count, these are the median average SDNN.

A good HRV number can easily exceed the median HRV ranges shown below, while HRV below the median can be a signal that you need to work on your health.

Generalized HRV number interpretation:-

• Below 20 ms: Very low

• 20-35 ms: Acceptable but low

• 35-45 ms: Average health

• 45-50 ms: Good

• Above 50ms: Great

While HRV decreases as one gets older, there are cases where people have actually increased their HRV range with age owing to their health dedication.

Please bear in mind that HRV average values are also correlated to Ethnicity as well.

Europe & Northern European people, in particular, have higher HRV, while in the subcontinent it tends to be lower.

What really matters are personal HRV trends. While it is easy to look at others' HRV data and be disappointed if yours was low, it really does not matter.

The idea is to track your HRV regularly and keep on making lifestyle, workout, habit behavioral changes etc that contribute to an overall improvement in your baseline HRV.

Tracking HRV over weeks and months, and correlating HRV trends with your LIFESTYLE CHANGES is the name of the game.

Mindbreath app

BENEFITS OF HIGH HRV

General benefits:-

- More productivity

- Better performance

- High immunity and resilience

- Multitasking easily

- Feeling of well-being

- Less fatigue

- Happier mental state

For Athletes:-

- High athletic output

- Performance under pressure

- Lesser risk of illness and injury

- Higher focus levels, more mental resources even under high physical exertion

HOW TO DEVELOP HIGH HRV

There is no single magic pill, it requires a holistic approach towards health and fitness in general.

SLEEP

Among the most important piece of the puzzle when it comes to health in general is sleeping and waking up on time and it has tremendous benefits for HRV.

Sleeping on time sets the circadian rhythm responsible for a healthy sleep and a healthy body clock.

Being consistent with sleep times is a key to set the body’s clock

Taking in the Morning Sun, watching the Sun set, avoiding screen time after sunset also benefit.

FOOD

Maintaining a certain balance in your diet is important, too less food with low calories and too much food with high calories should be avoided. Of course, unhealthy food will have a negative impact.

Also, eating on regular time is very important. Eating within the body’s circadian rhythm and other digestive and bodily processes greatly helps maintain optimum HRV.

It is worth experimenting with different fasting techniques and syncing overall perceived energy levels with HRV, certain fasting regimes can help boost HRV. As different people may need different regimes, this is something that needs to be done with certain levels of awareness on the user’s part.

STRESS MANAGEMENT

Stress definitely has a negative impact on HRV. It suppresses HRV as the nervous system remains focused on recovery and is unable to focus on optimum functioning.

Continuous exposure to long term stress over weeks and months leads to a much suppressed HRV and might result in long term health degradation.

WORKOUT

Definitely, a must do, physical workouts should boost your average HRV and result in long term gains for the body. While HRV decreases during and immediately after the workout as body is focused on recovery, it shall bounce back and boost baseline HRV.

Having said that, over-exertion can result in reduced HRV so it is important to manage training loads, monitor HRV and make adjustments accordingly to the current training type/loads. Lifestyle factors like diet, emotions etc also need to be considered when making adjustments.

ALCOHOL LIMIT

Alcohol severely and immediately affects HRVresulting in a drop. Even a few days after consumption, it may stay low and take 3-4 days to bounce back to its usual baseline. Alcohol should be reserved for special moments.

MEDITATION

As with all things meditation, it shall in theory boost HRV as it stands to reduce stress and improve clarity bringing the nervous system into a more sympathetic state.

DEEP BREATHING | BIO-HACKING

Resonant frequency breathing or simply put deep harmonious breathing instantly boosts HRV.

Deep harmonious breathing stimulates the Vagus nerve and results in RSA- respiratory sinus arrhythmia, meaning an increase in HR with inhales and a decrease with exhales.

Maintaining a certain harmonious breathing pattern boosts HRV significantly upto even 100% for the time period being practiced.

Most users using the MIndbreath app's 'compare Breathing HRV' feature which compares HRV during normal and deep breathing register an increase in 36% HRV, while some users report even 100% + change in HRV (arguably suppressed HRV opening up dramatically)

Harmonious breathing is very popular and preferred by many over Meditation as this gives instant results without the need to go into any meditative state, in-fact, users report that even 2-4 minutes of deep harmonious breathing results in a more calm and composed mind.

Practical applications of HRV-

• Diet management

• Workout regime tracking

• Sleep cycle management

• Maintaining stress levels

• Mental health

• Early signs of sickness

In-fact HRV tracking has potentially proved to help in early Covid detection as seen in this academic study. The study concludes-

Dramatic drops in HRV correlated with subsequent spikes in CRP in COVID-19 patients. Daily short-segment HRV readings may aid clinicians in the triage, disease progress monitoring, and treatment.

The commonly accepted hypothesis is that Heart rate registers an increase much later after any illness has set in while HRV drops well ahead of the first symptoms of illness giving a window to act in advance.

How to measure HRV

Mobile app | No extra sensors-

Mindbreath app - The simplest way is through your mobile phone with the Mindbreath app, advancements in signal processing have enabled PPG HRV measurements via most smart phones.

It uses the camera sensor as a HRV sensor without the need for any extra sensor via a validated method with accuracy levels comparable to dedicated monitors.

It measures your Heart rate and Heart rate variability and presents the data in an easy to understand graphical way with metrics like Stress, Energy and Health levels.

For advanced users, it also measures your Heart rate and all Heart rate variability components including Time domain and Frequency domain components.

Values calculated- bpm, sdnn, rmssdn, pnn50, pnn100, HF, LF, HF/LF ratio.

On-demand monitors-

Polar has been at the forefront of on-demand HRV monitoring with its chest strap range- Polar H10, it is widely considered a benchmark in the industry. Pairing the monitor with an app like EliteHrv is an easy way to monitor HRV even if you are in motion like a workout, but it requires a dedicated chest strap.

24x7 smart wearable-

Whoop band is among the best when it comes to 24x7 monitoring, though it uses its own algorithms and as of writing does not share raw HRV values via it’s app meaning on-demand reading is not possible. Though recently, Whoop did make it compatible with 3rd party apps to extract raw R-R intervals for measuring HRV with other apps.

Oura ring is another strong product providing strong bio-analysis, but it only measures HRV during sleep time and not during the day. Also, recording an on-demand reading with raw HRV data is not possible.