As smartwatches, also known as wearables, are becoming more popular, the amount of users can also access their health.
Statistics such as resting heart rate, V02 maximum (maximum oxygen consumption), and heart rate variability (HRV) provide valuable insight into your fitness level.
However, not all measurements are created equally.
HRVs have long been used by elite athletes to determine training schedules, but have become a “buzzword” among the wider community.
Matthew Ahmadi, assistant director of the University of Sydney Mackenzie Wearable Hub, says HRV has been around for over 20 years in a competitive sports environment.
“Over the past decade or so, it’s been really picked up among the general population, mainly due to the increased use of wearables,” says Dr. Ahmadi.
HRVs have been used for a long time in competitive sports environments. (Getty Images: SportsFile/Sam Barnes))
WHOOP, a leading wearable brand and official partner of the Women’s Tennis Association, collects data on the most consistent factors that boost or harm HRV.
According to global statistics for 2024, you’re most likely to improve your HRV by getting quality sleep, consuming caffeine and having consistent wake times, but consuming alcohol, getting sick and increasing stress will cause the numbers to crash.
So what can HRV measure and how can you use it to maximize your workout?
HRV shows how “balanced” the autonomic nervous system is
Dr. Ahmadi explains that HRV measures “inter-heart variability.”
The heart does not bump into one another (like a metronome or a clock).
Dr. Ahmadi explains that high HRV indicates that the autonomic nervous system is in “balance.” (Supplied by: Matthew Ahmadi))
So, while your heart may be beating at 80 beats per minute, there is a longer or shorter gap between each heartbeat.
How these gaps fluctuate determine HRV and indicate that more numbers are greater.
Many are ideal and indicate that the body is homeostasis (or balanced), says Dr. Ahmadi.
This is because HRV is a window into the autonomic nervous system.
The autonomic nervous system consists of two major divisions: the parasympathetic and sympathetic nervous system.
In simple terms, the parasympathetic nervous system is responsible for the “rest and digestion” process, while the sympathetic nervous system is involved in the “combat or flight” response.
Ideally, Dr. Ahmadi says the two are well balanced. In other words, the body responds equally to both inputs.
“The more someone fits, the more their bodies can adapt to a variety of stressors and thus recover better,” he says.
Your HRV score is best understood as a window into the automatic nervous system. (Supply: whoop))
However, when HRV is low, it indicates that one branch of the autonomic nervous system is dominated.
“It generally means your sympathetic system is dominant, so your body is on a high alert state.”
HRV shows how you are “ready”
When HRV is measured, it is also important for interpretation.
Measuring it before you go to bed will tell you how well your body has recovered from the activities and stressors of the current day, says Dr. Ahmadi.
“[Measuring HRV] Immediately after you wake up, you will be very clear about what your body is ready to handle on the day that comes,” he adds.
When your HRV is read will determine how it should be interpreted. (Supply: whoop))
This is the main reason why HRV offers an advantage over other measures of fitness.
A higher HRV not only shows a higher level of fitness, but can also be used to determine what level of intensity to take on in your current athletic regime.
“In the world of sports science, HRV is considered a proxy for “preparation.” [to train]”Something says Kristen Holmes, a leading scientist at Hoops.
Kristen Holmes is the global head of Hoop’s global performance. (Supplied: Christen Holmes))
“Higher HRVs give you a higher ability to train, while lower HRVs give you a lower ability to train.“
WHOOP uses HRV to determine a user’s daily “recovery” score and rated it as green, yellow, or red.
On green days, users are encouraged to “all out,” while on red days, “active recovery” activities such as meditation, light walking and yoga are recommended.
There are studies showing that many elite athletes likewise use HRV to adapt their athletic regimes, and that those who do so achieve better performance outcomes.
WHOOP uses HRV to determine the “recovery score.” (Supply: whoop))
Factors that improve or reduce HRV
WHOOP also collects data on the most common positive and negative impacts on HRV.
Positive factors include following healthy diets, being well hydrated, quality sleep, and maintaining consistent sleep and wake times.
“That’s a big measure of it and it’s really frustrating,” says Dr. Holmes.
“It’s difficult to accurately identify what can’t be dealt with in a functional way and adapt to external stressors.”
However, there is a consistent factor that lowers HRV, with alcohol consumption at the top.
In fact, Dr. Holmes says that alcohol is a very “HRV crusher” and that 89% of people using platform reports reduce alcohol consumption in the long term.
Overall, alcohol consumption has been found to reduce HRV. (Getty Images: Gregory Lee))
“That’s because people can see the performance costs directly from actions,” says Holmes.
“Your coach can tell you, ‘Hey, alcohol is really bad for your performance’, but until you see firsthand how it affects your HRV, you… wow, I’m a lesser version of myself today. It’s calming down. ”
| “Boost” HRV | “Harmony” HRV | |
|---|---|---|
| 1. | Sleep quality and duration | alcohol |
| 2. | Caffeine | heat |
| 3. | Consistent wake-up times | Sleep at altitude |
| 4. | Consistent bedtime | High stress zone |
| 5. | Daytime meal | disease |
| Source: WHOOP 2024 review user data | ||
However, do not compare your HRV score with others.
Generally, the older you get, the lower your HRV, but women tend to have a lower HRV on average.
If you want to improve your HRV, it is recommended that both Dr. Ahmadi and Dr. Holmes get baseline levels and determine changes related to their score.
In general, comparing your HRV score with others is useless. (Getty Images: Thomas Berwick))
Don’t panic if your HRV is low
It is also important to note that low HRV is not always bad.
As an example, Dr. Ahmadi states that if you are previously sedentary, you should expect a drop-off of your HRV, especially if you are starting a new exercise program.
“In the first few weeks, you are likely to be significantly reduced to your HRV every day,” he says.
“However, ideally, if the program works the way it should be, then seeing HRV increase over the coming weeks and months will make your body adapt to the current program load.”
Once your HRV starts to stabilize, it’s a good indication that you’re ready to “progress” the program.
However, if your HRV doesn’t show any improvement, you may need to remove your foot from the pedal.
“If you see a big drop-off, it’s a good idea not to push too hard, as it gives your body a sign that you need time to heal the next day,” he says.
“When you settle into a new training regime, your body will be able to adapt and handle higher stress and workout loads closer.”
