Heart rate variability is now a common smart watch fitness stat. What does it mean for your exercise load?

As the popularity of smart watches, they are also called wearables, it also increases, so does the amount of data that users can access about their health.

Statistics such as resting heart rate, V02 Max (maximum oxygen consumption) and heart rate variability (HRV) provide a valuable vision of their aptitude levels.

But not all measurements are the same.

While elite athletes have used HRV for a long time to issue their training schedule, it has become a “fashion word” among the broader community.

Matthew Ahmadi, deputy director of the Mackenzie Wearable Devices Center of Sydney University, says that HRV has existed for more than 20 years in the competitive sports environment.

“In the last 10 years or so, it has really recovered among the general population, mainly due to the increases in the use of portable devices,” says Dr. Ahmadi.

Whoop, a leading portable brand and official partner of the Women’s Tennis Association, has been collecting data on the most consistent factors that increase or damage their VRV.

The 2024 global statistics show that sleeping quality, consuming caffeine and having a constant vigil time is more likely to improve your HRV, while consuming alcohol, being sick and highly stressed will see that your numbers crash.

So what does HRV measure and how could I use it to maximize your training?

HRV indicates how ‘balanced’ is your autonomic nervous system

Dr. Ahmadi explains that HRV measures “variation between heartbeat.”

The heart does not hit constantly (like a metronome or clock).

So, while your heart can beat 80 beats per minute, there will be longer or shorter gaps between each beat.

How are these gaps variable determines your HRV, with a higher number that indicates greater variability.

A high number is ideal and an indication that the body is in homeostasis (or balanced), says Dr. Ahmadi.

This is because HRV is a window to the autonomic nervous system.

The autonomic nervous system consists of two main divisions: parasympathetic and sympathetic nerve systems.

In simplistic terms, the parasympathetic nervous system is responsible for “rest and digested” processes, while the sympathetic nervous system is responsible for “struggle or flight” responses.

Ideally, says Dr. Ahmadi, the two are in equilibrium, which means that the body also responds to both entries.

“The more someone is, the more your body can adapt to different stressors and, therefore, recover better,” he says.

But if your HRV is low, it indicates that a branch of the autonomic nervous system is dominating:

“It usually means that your sympathetic system is dominant, so your body is on maximum alert.”

HRV indicates how ‘ready’ is to exercise

When your HRV is measured, it is also critical for your interpretation.

Measure it before bedtime will tell you how well the body has recovered from the stressful activities or factors of the current day, says Dr. Ahmadi.

“[Measuring HRV] Just after he wakes up he will give him a good indication of what his body is prepared to handle during the next day, ”he adds.

This is the key reason why HRV offers an advantage over other physical condition measures.

A higher HRV not only indicates a higher level of physical condition, but can also be used to dictate what level of intensity you should assume in the exercise regime of your current day.

“In the world of sports sciences, we think of HRV as a ‘preparation’ proxy [to train]”Kristen Holmes, the main whoop scientist, says.

WHOOP USA HRV to determine the daily “recovery” scores of their users, qualifying them as in green, yellow or red.

On green days, Whoop encourages users to “everything outside”, while on a red day, recommends activities of “active recovery” such as meditation, light walking or yoga.

Many elite athletes similarly use HRV to adapt their exercise regimes, and the research that shows those who do achieve better performance results.

Factors that improve or decrease HRV

Whoop also collects data on the most common positive and negative influences in HRV.

Positive factors include being well hydrated, following a healthy diet, sleeping quality and maintaining consistent sleep times and vigil.

“That is what makes it a great measure and really frustrating,” says Dr. Holmes.

“Sometimes it is difficult to identify exactly what does not allow me to respond and adapt to external stressors functionally.”

However, there are consistent factors that reduce the HRV, the upper part being alcohol consumption.

In fact, Dr. Holmes says that alcohol is a “HRV crusher” that 89 percent of people who use the platform report that decreases long -term alcohol consumption.

“This is because people can directly see the cost of performance of their behaviors,” says Holmes.

“Your coach can tell you: ‘Hey, alcohol is really bad for your performance’, but until you see how it affects your HRV, you are like … Wow, I am a minor version of myself today. It’s alencing.”

But you should avoid comparing your HRV scores with those of others.

In general, as it ages, less will be their HRV, while women also tend to have a lower HRV on average.

If you want to improve your HRV, both Dr. Ahmadi and Dr. Holmes advise to take a reference level and judge any change in relation to their own scores.

Don’t be scared if your HRV is low

It is also important to keep in mind that a low HRV is not always bad.

As an example, Dr. Ahmadi says that he must expect to see a fall in his HRV if he is starting a new exercise program, especially if he was previously sedentary.

“In the first weeks, you are likely to see a great decrease in your HRV daily,” he says.

“But ideally, if the program works as it should be, you should begin to see that your HRV increases in the coming weeks and months, and then decreases as your body adapts to the load of the current program.”

Once your HRV begins to stabilize, it is a good indication that you are ready to “progress” your program.

But if you do not see an improvement in your HRV, you are likely to take your foot from the pedal.

“If you see a great fall, then it is a good idea not to press so much the next day, because your body is giving you signs that you need time to recover,” he says.

“As you accommodate in a new training regime, your body will adapt and you can handle greater stress and training loads closer.”