Category Archives: HRV Training

Using HRV for Improved Sports Performance

Most athletes know that getting enough rest after exercise is essential to high-level performance, but many still over train and feel guilty when they take a day off. The body repairs and strengthens itself in the time between workouts, and continuous training can actually weaken the strongest athletes. In competitive sports, improved performance is achieved by alternating periods of intensive training with periods of relative rest. Rest is physically necessary so that the muscles can repair, rebuild and strengthen. For recreational athletes, building in rest days can help maintain a better balance between home, work and fitness goals.

While standardized training programs produce well documented results, they do not take individual responses into account. Age, gender, race, baseline fitness level, and genetic factors are known determinants of individual differences in responses to endurance training. In addition the status of the nervous system plays an important role in training response.

Heart Rate Variability (HRV) is a view into the nervous system and can be used to guide an optimal training program. Never heard of the term? You are not alone. Measuring HRV, though long used in hospitals for treating heart patients, is a relatively new biofeedback concept for endurance athletes. Soviet Union sports scientists started keeping track of their elite athletes’ HRV in the ‘70s. In the past decade, college sports teams and world-class athletes have been increasingly using HRV to monitor fatigue and recovery from workouts. There are numerous clinical studies on HRV and training.

The introduction of athletic heart rate monitors that communicate with smart phones has enabled HRV monitoring capability to anyone who has a smart phone and wants to use it to guide training.

SweetBeat is an iPhone app by SweetWater Health that has custom capability for athletes to track their HRV. The athlete simply does a 3 minute HRV session each morning and is presented with a result that recommends “train as usual”, “low exertion day” or “rest day” based on the individual’s baseline trend. New SweetBeat updates include power frequency graphs and audio alerts.

The new SweetBeat power frequency graphs display the LF (low frequency) and HF (high frequency) components of HRV. LF and HF are bands of the HRV power spectrum.  The LF power level represents both branches of the nervous system, the sympathetic (fight or flight) and parasympathetic (rest and recovery).  The HF power level is a reflection of the parasympathetic branch of the nervous system, and responds quickly to rest and recovery.  Both LF and HF are expressions of overall fitness and resilience.  These power levels are relatively high when the nervous system is active and flexible.  Typically, these power levels range from 800 to 1000 for fitness enthusiasts and 6000-8000 for elite athletes as measured in the SweetBeat application. This feature provides important additional information about the nervous system and fitness levels. Tri-athletes and more advanced users have requested this feature. Along with a graph representing the power frequencies over time, a real time graph will show your power for each session.

Good luck with your training! If you have any questions you can email us at support@sweetwaterhrv.com and we will reply within 24 hours. Don’t have SweetBeat, yet? Download SweetBeat on iTunes now!

SweetBeat Tuned for Athletic HRV Training

Front crawl swimmer speeding through the pool

 

Many of you are athletes or fitness-focused individuals and currently use SweetBeat to monitor and track your HRV as it correlates to your training routine. In an effort to better meet your needs, we have added some features that are specifically designed for HRV recovery and training.

The latest release of SweetBeat can now be downloaded from the App Store.

When you press start, you can view a selection screen to monitor stress, run HRV For Training session or run a Heart Rate Recovery session. If you select the Help icon (question mark in a box) at the right of each session type, you will see the following screen.

Session Selection Screen

Select session

 

You can learn about the HRV For Training feature set by swiping to the left after you select the help ? button. The following six screens give you an overview of the new SweetBeat functionality.

 

Screen1

 

Screen2

 

Screen3

 

Screen4

 

Screen5

 

HRV for Training over time

 

To run an HRV For Training session, select the session option, and press the start button on the main monitor screen. SweetBeat will automatically filter your HRV readings from your heart rate monitor and begin counting down a three-minute session.

The SweetBeat learning algorithm will establish a reference line over a few days as shown in the HRV For Training Over Time graph.

We recommend that you initially do light training or no training for a couple of days.  If you do train during initial sessions, the algorithm will compensate and adjust over the first 10 days of use, improving accuracy over time.

The HRV For Training Over Time graph will provide recommendations after each daily reading for a regular training day (HRV is above reference line), a light exertion day (HRV is below reference line for one day), or a rest day (HRV is below the reference line for two days).

If you wish, SweetBeat will remind you to take a daily HRV reading, with a selectable time that you preset. This reminder will appear initially when you select your first HRV training session. If you want to change the daily reminder time, you can access the preset in the settings menu under application settings.

Daily Reminder Setting

Daily Reminder

 

Charts for each session are included in history tab as well as cumulative charts for all sessions. HRV training sessions are tagged as HRV in the history screen.  You can also still select your own tag.

Good luck with your training! If you have any questions you can email us at support@sweetwaterhrv.com and we will reply within 24 hours.

SweetBeat Gets the Blues

Bluetooth is a wonderful invention. It enhances the mobility of the athlete, who no longer has to mess with wires while working out. It’s also a boon to the person who likes to garden or do other chores while listening to music. (I know one gentleman who bought Bluetooth headphones because he liked to garden while listening to music and snipped his wires with the garden shears once too many times.)

But when it comes to heart rate variability, not all Bluetooth is created equal. When SweetWater Health came out with our Bluetooth-compatible version of SweetBeat™, we tested several BT sensors to assure accuracy. Heart rate requires a lower sampling rate, and all sensors performed well for heart rate detection. But HRV requires a more frequent sampling rate to be accurate, which is why the iPhone camera sensor, at 30 frames per second, cannot deliver accurate HRV data.

You can use any Bluetooth v4.0 low-energy heart rate monitor with SweetBeat, including 60Beat and newer Polar H7 models with the iPhone 4S, 5, iPad 3 and newer iPod Touch 5 devices—with one exception. You cannot use Wahoo Blue HR. It’s fine for heart rate, but is not suitable for heart rate variability. This is noted in the app store description of SweetBeat.

We’re sorry for any inconvenience this may cause our Wahoo Blue HR owners. We have worked closely with Wahoo on this issue, but as of this writing, the technical issues have not yet been resolved.

Questions? Please contact us at info@SweetWaterHRV.com.

Important Information for SweetBeat Users

SweetWater Health is a very young company. SweetBeat™, our iPhone app, has been on the market for just a little over a year. We started with no users at all (except for us SweetWaterites), and during the months that followed SweetBeat’s debut, we have watched with interest as our audience of users has grown.

And you, our users, have surprised us. We thought that most people would purchase SweetBeat to help reduce stress. There are certainly some users that fit that profile, but the dedicated users, the ones who really use SweetBeat all the time, are athletes—often elite athletes—who use SweetBeat for HRV training to help understand their bodies better and to optimize training schedules.

And you—our dedicated users—told us that the product needed tweaking so you could use it even more effectively. So tweak it we did, and we need to tell you about the changes we made. This is important to know even if you are not an athlete, as your HRV levels will appear lower than in previous versions. This does not mean your HRV has changed—only the scale.

SweetBeat version 1.2.2 (and beyond) includes a refinement of the HRV calculation algorithm to fine-tune it for athletes. Some of you ultra-fit individuals were “maxing out” the HRV reading at 100. The new algorithm fixes this with the result that the calculated HRV will appear lower than in previous versions of SweetBeat. We have included some charts to illustrate what you can expect with version 1.2.2.

For SweetBeat users who have been measuring HRV for athletic training, your HRV will appear to decrease with version 1.2.2. For this reason we recommend starting with a new baseline taken on a day that you know you are fully recovered. We believe this will provide more accurate results in the long run as your fitness levels improve.

Below are a couple of charts that illustrate how your new HRV scores may differ from your previous scores.

How is HRV calculated? SweetBeat measures the RR intervals (the time between heartbeats) then calculates the HRV parasympathetic parameter rMSSD. We then run a scaling algorithm on rMSSD to create an HRV value. Typical values will be in the range of 0-100. rMSSD is the square root of the mean squared difference of successive RRs. Elite athletes will experience very high rMSSD scores compared to others.

If you want to see the raw numbers, look at the “Geek Screen” on the flip side of the ECG heart beat screen. To see the Geek Screen, press the button in lower right corner of the window where the animated ECG appears. You will see the summary numbers from your last session. Below are the same charts from above that include rMSSD.

As a reminder on how to use HRV for training:

  1. Take your HRV every morning prior to any activity.
    1. This session can be measured sitting, standing or lying down, but be consistent in the position you select.
    2. Do a five-minute session.
      1. HRV is time dependent so be consistent in the length of the session
      2. If HRV drops significantly (more than 10 points) a low exertion or rest day is in order.
      3. If HRV drops significantly two or more days in a row, a rest day is in order.

Questions? Please send them to support@sweetwaterhrv.com. We’d love to hear from you.