Weekly HRV vs. Daily HRV

As you seek to optimize your health or performance, it is a best practice to regularly check your progress and make adjustments to continue to get the best results.

This post explains why daily and weekly “optimization check-ins” generally produce the best results. I will also explain when to use daily and when to use weekly, and why daily and weekly HRV monitoring is so important.

Optimizing Your Plan

Even if you have a well designed health or performance plan, it is important to regularly check your progress and adjust/optimize your plan for the best results.

An important part of any program design is to define which objective and subjective data points will indicate positive or negative progress.

An important part of any program design is to define which objective and subjective data points will indicate positive or negative progress.

Example subjective measures for a health or performance plan might include:

• Perceived energy levels
• Perceived exercise exertion
• Mood
• Motivation
• Sleep quality

Example objective measures might include:

• Body weight
• Heart Rate Variability
• Blood markers
• Fitness benchmarks
• Performance markers

Heart Rate Variability is a powerful objective value that is the “glue” that binds other markers together. HRV can indicate systemic condition at any point in time during a program. In context with other metrics, it can help you accurately understand what is working and what is not working and guide optimization choices throughout your journey.

Heart Rate Variability is a powerful objective value that is the “glue” that binds other markers together.

So how often should you be tweaking your program?

In general, assuming you have meaningful information to review, the more frequent you check your progress and make optimizations to your lifestyle or training plan, the better results you can get over the long term.

This does not mean jumping from program to program frequently or overreacting to small setbacks or changes. It is also possible to adjust your program too frequently or to be too granular with your tweaks. Some adaptations and changes simply take time. In other cases, if the effort that it takes to optimize your health or training plan exceeds the amount of benefit you will get from changing it, then it is better to make changes a less frequently.

The ideal window for optimizing based on acute short-term changes in Heart Rate Variability falls somewhere between daily and weekly.

Daily Heart Rate Variability Values

The leading Heart Rate Variability platforms recommend taking a daily short (under 5 minute), rested HRV measurement. Obtaining the data is easy enough, and even analyzing it is done for you by HRV apps. But actually tweaking your training and lifestyle choices on a daily basis can be time consuming and unnecessary depending on your situation.  

So before we learn when to use daily HRV optimization and when not to use it, let’s review what we can learn from it.

Changes in Heart Rate Variability from day-to-day provide very granular and powerful information about how daily lifestyle stressors and recovery choices affect your acute systemic situation (namely your Autonomic Nervous System). Since HRV can show ANS effects before symptoms arise, these daily HRV insights afford you the opportunity to tweak your plan more frequently and effectively to maximize your potential.

Since HRV can show ANS effects before symptoms arise, these daily HRV insights afford you the opportunity to tweak your plan more frequently and effectively to maximize your potential.

With daily HRV measurements you can gain insight into:

1. How recent sleep quality/duration is affecting your body
2. How exercise from the past few days is affecting your body
3. If any accumulation of fatigue or systemic stress is suddenly taking effect
4. If your immune system may be elevated today
5. How your current stress load or recovery status for today compares to your recent history

These and so much more can easily be reviewed on a daily basis with appropriate additional contextual data.

Sometimes daily changes in HRV are dramatic, and other times they are negligible. So when does it make sense to make optimization tweaks to your plan based on daily HRV values?

How and When to Use Daily HRV Optimization

If small changes have a large impact on progress towards reaching your goals then daily HRV optimization is right for you.

What does this mean?

For exercise/training:

Small tweaks to one exercise session have barely any effect on an elite athlete’s long term performance. But for a general health and fitness seeker, a small change to your workout could be the difference between overdoing it, under doing it, or getting it just right.

Small tweaks to one exercise session have barely any effect on an elite athlete’s long term performance. But for a general health and fitness seeker, a small change to your workout could be the difference between overdoing it, under doing it, or getting it just right.

For health:

Small changes in acute health status can have a drastic effect on productivity, motivation, energy, or quality of life. In this case, it would be very helpful to know where on the spectrum you were starting out each day and how the past few days have impacted you. If HRV indicates a less favorable starting point on a given day, you know to take measures to avoid harmful situations or proactively emphasize choices that improve your acute health status.

Weekly Heart Rate Variability Values

Along with daily HRV monitoring, you can also gain a deeper understanding of how your lifestyle choices are affecting your progress by looking at your weekly averages and weekly HRV changes.

Some stressors can have a delayed response on your HRV and will not show an effect for a couple of days after the stressor occurs. The timing of your swing from Sympathetic to Parasympathetic could vary also depending on other lifestyle factors and your resilience to the specific type of stressor. This is where weekly HRV monitoring and tweaking can be more beneficial for some people than daily HRV adjustments.

The timing of your swing from Sympathetic to Parasympathetic could vary also depending on other lifestyle factors and your resilience to the specific type of stressor. This is where weekly HRV monitoring and tweaking can be more beneficial for some people than daily HRV adjustments.

Assuming adequate data, weekly HRV values can show you:

1. How were my daily decisions adding to my overall progress?
2. Did the stress I accumulated this week meet, exceed, or fall short of my recovery ability?
3. Based on #2, how can I tailor the coming week to maximize my results?

It is important to emphasize that in order to make effective weekly decisions, you still need to take daily HRV measurements.

How and When to Use Weekly HRV Optimization

Who should be making weekly optimizations based on Heart Rate Variability? Everyone. Athletes, health seekers, law enforcement officers, inpatients, outpatients, daily optimizers, everyone.

The weekly time frame for optimizing health or performance is still granular and acute, but it is also very manageable. Once a week you can check-in with yourself, your doctor, or your coach, and determine what went well last week and what to focus on next week.

The weekly time frame for optimizing health or performance is still granular and acute, but it is also very manageable.

For daily optimizers: A daily change in HRV can be significant and important, but it is only one data point. If something happens once or twice, it isn’t necessarily a trend. With regards to HRV, health, and performance – a week’s worth of data can help spot a meaningful trend. The weekly trend also lets you know if the sum of your daily choices that week are helping your progress or hurting it.

For exercise/training: If you are a competitive or elite athlete, it takes a significant volume of stress to elicit deeper adaptations and affect your progress. This means that aside from avoiding injury, changing one single workout in your plan will likely be more work than it’s worth. But understanding the cumulative stress from a week’s training and then either tweaking the following week’s training (or even better – tweaking recovery) can have a huge impact on long term results.

For health: Most health seekers should be making some sort of daily optimizations. However, if daily changes are not moving the needle, or if you are a health optimizing veteran, then weekly monitoring should be sufficient to keep tabs on your health status without spending the extra time to optimize daily.

If small changes don’t have a large impact on your progress, but larger changes to cumulative stress do then weekly HRV optimization is better for you to focus on than daily. Hint: Larger changes to cumulative stress impact everyone’s progress.

If small tweaks to your program don’t have a large impact on your progress but larger changes to cumulative stress do then weekly HRV optimization is better for you to focus on than daily.

There are two specific values that make analyzing weekly HRV and deciding on plan optimizations much easier: Weekly Mean HRV and Weekly HRV Coefficient of Variation.

Weekly Mean HRV:  This is an average of your daily HRV values throughout the week.

• If your weekly average HRV is declining, your accumulated stress has likely exceeded your capacity to recover
• If your weekly average HRV is level, you are likely no better and no worse than the previous week (subjective/contextual information will tell)
• If your weekly average HRV is increasing, and contextual/subjective information is favorable, you are likely increasing health or capacity to perform

There are plenty of cases where a higher HRV isn’t always better, and a lower HRV is desirable or expected. For example, an experienced athlete may purposefully overreach and cause HRV to decline for a few weeks before deloading and recovering back to, or above, the original values. Also, certain mild illnesses cause a drastic increase in immune system function which can cause HRV to increase rapidly.

More examples are covered within the Foundations of Heart Rate Variability course.

Weekly HRV Coefficient of Variation (HRV CV): This subject will require an entire post of its own. In a nutshell, the weekly CV tells you how much your HRV has changed throughout the week (both up and down) relative to your average HRV.

If your Heart Rate Variability values have little fluctuation throughout the week, then the Coefficient of Variation of your HRV for that week would be low.

If your Heart Rate Variability values have high fluctuation day to day, then your weekly average might be the same, but your weekly HRV CV will likely be very high.

• A high weekly HRV CV generally indicates that your body experienced new stressors, acutely strong stressors, or accumulated stressors throughout the week. HRV researcher Andrew Flatt mentions that a weekly CV above 7% seems to be the threshold for “high CV” with the athletes he has worked with.
• A low weekly HRV CV generally indicates that not much changed throughout the week. Either you were well adapted to whatever stress you encountered throughout the week, or your system was unable to recover well.

A high weekly HRV Coefficient of Variation (CV) generally indicates that your body experienced new stressors, acutely strong stressors, or accumulated stressors throughout the week while a low weekly HRV CV generally indicates that you either were well adapted to whatever stress you encountered throughout the week or your system was unable to recover well.

Combining Weekly Mean HRV and Weekly HRV CV

Alone, these values does not give the complete picture. A low HRV CV could be really good or really bad depending on the situation, plan and goals.

Combining Weekly Mean HRV and Weekly HRV CV can give very accurate and objective insight into how your week progressed and what you can do differently next week to improve. To make more targeted adjustments to your program, it is important to include contextual information such as average sleep duration, perceived sleep quality, exercise performance stats, changes in body weight, blood pressure, or whatever is most relevant to your situation.

Beyond Daily and Weekly

Daily and weekly changes in HRV target acute changes in health and performance. Weekly HRV is the smallest meaningful trend that is available to most people.

Even though daily and weekly optimizations are very powerful and highly recommended, long term trend analysis is still very important and often overlooked. The details of long term trending of months, seasons, year, etc. is beyond the scope of this post. But if your daily, and especially your weekly, optimizations are on target, then your long term trends will show it.

If your daily, and especially your weekly, optimizations are on target, then your long term trends will show it.

Takeaways

Daily HRV monitoring and optimizations are best used in cases where small changes to a plan program make a larger impact. General health and recreational fitness seekers most often fall into this category. This group should also use weekly check-ins to determine if their daily decisions are helping or hurting.

Weekly HRV monitoring and optimizations are best used in cases where small daily changes won’t drastically affect the outcome for the week. A week’s worth of data with daily context can provide a deeper insight than daily changes alone can provide. Competitive athletes or those with a more rigid schedule often benefit most from weekly optimization instead of daily.

Longer term trends are useful for determining if daily and weekly optimizations are working.

Interested in learning more about the science behind HRV and how monitoring it can help improve your health and performance? Get access to the “Foundations of Heart Rate Variability” course here!