Blog post by Marco Altini
Inspired by the different analysis that our users started putting together to investigate the effect of various stressors (training, travel, alcohol intake, etc.) on their HR and HRV we redesigned the Acute HRV Changes analysis Insight.
Instead of looking only at day to day variations following training (is your HRV reduced after more intense workouts?) we will let you pick different parameters and explore day to day (acute) variations not only with respect to training but also for alcohol intake, travel, sick days and menstrual cycle.
This way you'll be able to analyze more systematically over periods of 3 months how your body is responding to these different stressors, instead of only looking at them anecdotally from the history page.
The new acute HRV changes analysis will be available in about a week.
What's an acute change anyways?
We talked about acute HRV changes a couple of times already. Acute stressors are events that affect your physiology in the immediate future. Think about an intense aerobic workout, an intercontinental flight, a night out with too many drinks, high caffeine intake, etc. Acute stressors are typically the easiest phenomena to interpret and reproduce, and looking at data in the context of acute stressors can help understanding how your physiology works. Looking at acute changes can also help in gaining confidence in the tools we use, as these changes should be captured more easily. Check out this post for some examples from our users, or this tweet, the latest example I could find. In the past we focused much on acute changes in response to training, which we also published in our first paper, however we wanted to provide you with a better way to explore your data and annotations, hence the redesign of this feature.
It's important also to remember that physiology is complex, and while acute HRV changes are often repeatable and easy to understand, there might be other factors behind the relationships that we are seeing (or not seeing) in our data.
How does it work?
In the new Acute HRV Changes analysis you will be able to look at acute changes in two different ways. For certain stressors, which have an impact on the following day physiology (e.g. alcohol intake or a workout), we will show you the difference in HRV between "today" (stressor day) and "tomorrow" (day after the stressor), averaged over three months of data. Did your HRV decrease after a certain event? By how much? Is this decrease consistent? That's what you will be able to see for training (rest vs training as well as different annotated intensities) and alcohol intake. On the other hand, some stressors last for several days (for example getting sick, menstruation and travel). For these stressors we will not look at day to day changes but at the average HR or HRV values in the two conditions. What's your normal HR? Does it change when sick? Hopefully, this is clear, otherwise you just need to wait a couple more days to play around with the update. See some additional screenshots below.
The same feature is available also in HRV4Training Coach, where you will also be able to select different time frames, and analyze acute stressors for periods ranging between 30 to 90 days. For teams and coaches, you'll be able to run this analysis on all your athletes, as shown below for a few examples.
We hope you'll enjoy the feature :)
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1. Intro to HRV
2. How to use HRV, the basics
3. HRV guided training
4. The big picture
5. HRV and training load
6. HRV, strength & power
7. Overview in HRV4Training Pro
1. Context & Time of the Day
3. Paced breathing
4. Orthostatic Test
5. Slides HRV overview
6. rMSSD vs SDNN
7. Normal values and historical data
1a. Acute Changes in HRV
1b. Acute Changes in HRV (population level)
1c. Acute Changes in HRV & measurement consistency
1d. Acute Changes in HRV in endurance and power sports
2a. Interpreting HRV Trends
2b. HRV Baseline Trends & CV
3. Tags & Correlations
4. Ectopic beats & motion artifacts
5. HRV4Training Insights
6. HRV4Training & Sports Science
7. HRV & fitness / training load
8. HRV & performance
9. VO2max models
10. Repeated HRV measurements
11. VO2max and performance
12. HR, HRV and performance
13. Training intensity & performance
14. Publication: VO2max & running performance
15. Estimating running performance
16. Coefficient of Variation
17. More on CV and the big picture
18. Case study marathon training
Camera & Sensors
1. ECG vs Polar & Mio Alpha
2a. Camera vs Polar
2b. Camera vs Polar iOS10
2c. iPhone 7+ vs Polar
2d. Comparison of PPG sensors
3. Camera measurement guidelines
4. Validation paper
5. Android camera vs Chest strap
6. Zoom HRV vs Polar
7. Apple Watch and HRV
8. Scosche Rhythm24
9. Apple Watch
1. Features and Recovery Points
2. Daily advice
3. HRV4Training insights
4. Sleep tracking
5. Training load analysis
6a. Integration with Strava
6b. Integration with TrainingPeaks
6c. Integration with SportTracks
6d. Integration with Genetrainer
6e. Integration with Apple Health
6f. Integration with Todays Plan
7. HRV4T Coach advanced view
8. Acute HRV changes by sport
9. Remote tags in HRV4T Coach
10. VO2max Estimation
11. Acute stressors analysis
12. Training Polarization
13. Custom desirable range / SWC
14. Lactate Threshold Estimation
15. Functional Threshold Power(FTP) Estimation for cyclists
16. Aerobic Endurance analysis
17. Intervals Analysis
18. Training Planning
19. Integration with Oura
20. Aerobic efficiency and cardiac decoupling
1. HRV normal values
2. HRV by sport
3. HRV normalization by HR
4. HRV 101