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Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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August 13 2015

Introducing PrimalBeat HRV

By Mark Sisson
67 Comments

Regular Mark’s Daily Apple readers know of my enthusiasm for the cutting edge biofeedback technology known as heart rate variability (HRV). There is a detailed introductory post here, and a follow up post here. In short, HRV measures the variation in beat-to-beat intervals of your heart, providing a direct window into the functional state of your autonomic nervous system. A high HRV score (indicative of more variation in beat to beat intervals) suggests a synchronistic balance between your parasympathetic (“rest and digest”) nervous system and your sympathetic (“fight or flight”) nervous system. A lower than normal (for the individual) HRV score is indicative of sympathetic dominance—a state of overstress or poor cardiovascular function.

While resting heart rate has long been the gold standard to measure an athlete’s general state of stress and recovery, HRV takes biofeedback to the next level by delivering more nuanced readings that accurately reveal conditions like hyper-arousal or burnout. This is critical because when you are under the influence of fight or flight hormones (as in, most of the time in hectic modern life), it’s difficult to tell when you are overstressed and heading for burnout.

The more you study the intricacies of HRV, the more interesting it gets. Some experts claim that deliberate breathing practices can elevate HRV—meaning that you can be alerted to and learn to regain sympathetic/parasympathetic balance when things get hectic. Serious athletes use HRV to govern training decisions—ensuring they are fully recovered before attempting breakthrough workouts, or undergoing forced rest periods (even when they feel fine subjectively) when HRV readings are suppressed.

I’m so enthusiastic about promoting the concept of HRV that I partnered with the industry leaders at Sweetbeat Life LLC to create a customized iPhone app called PrimalBeat HRV. You can purchase PrimalBeat HRV for $10 at the App Store (sorry, no Android version yet, coming soon…) and get started with daily HRV monitoring on your iPhone, iPad, or iPod Touch. Of course, you will also need a Bluetooth (ideally Bluetooth Low Energy (BLE 4.0)) enabled chest strap to pair with your iPhone. If not, you can grab a Polar H7 strap for 50 bucks on Amazon. I mention Polar since they have been the leading heart rate monitor brand for decades, but other great products like the Wahoo chest strap (60 bucks on Amazon) and any other Bluetooth enabled chest strap will sync with your PrimalBeat HRV app.

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It’s important to take an HRV measurement at the same time, under the same conditions (e.g., first thing in the morning, relaxing in bed), every day for as long as two months to establish an accurate baseline range off of which you can base your training and lifestyle decisions. PrimalBeat HRV allows you to archive each day’s morning reading with the touch of a button, and view your HRV readings (including the important HF and LF frequency scores—details in this podcast with HRV expert Ronda Collier) over time in a convenient graphic layout. For example, if you proceed with measurements over two months of normal lifestyle circumstances and training patterns and see most every HRV score falling between 65 and 75, this becomes your baseline range. If, on the heels of stressful events like jet travel, challenging workouts, or insufficient sleep, you obtain an HRV score in the 50s, this is a strong sign to back off on training and other stressors until your HRV scores return to normal range.

I will cover the topic of HRV in great detail in the upcoming Primal Endurance book, slated for release in early January, 2016. Brad Kearns, my Primal Blueprint Publishing sidekick and writing partner on Primal Endurance, relates an interesting story in the book where he experienced a delayed HRV suppression 36 hours after a stressful workout, but no change in resting heart rate over the same time period. With his more detailed biofeedback, he stayed in rest mode despite feeling fine and have a “green light” resting heart rate. Over time, these are the kind of training decisions that enable uninterrupted improvement and prevent burnout. To put it more simply, HRV can often be smarter than you when it comes to regulating the stress patterns of your workouts and life.

If you are an iPhone user, check out this app and start getting into it. Android users can look for other HRV software such as iThlete. If you’ve been tracking HRV for a while, please comment on your experiences. I’d love to hear your thoughts.

Note: If you’re familiar with Sweetwater Health’s existing Sweetbeat Life HRV app, PrimalBeat HRV uses the identical top of the line mobile HRV technology. The Sweetwater folks agreed to customize their product and brand it Primal in pursuit of our mutual interest of promoting HRV to as many folks as possible. Furthermore, Sweetwater Health is providing the customer support for PrimalBeat HRV app, so either of the branded products you choose is great.

Prefer listening to reading? Get an audio recording of this blog post, and subscribe to the Primal Blueprint Podcast on iTunes for instant access to all past, present and future episodes here.

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67 thoughts on “Introducing PrimalBeat HRV”

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  1. I’m notoriously bad at knowing if I’m ready for a workout or not — my brain ALWAYS wants to hit the gym or the trail. Far too often, my desire to workout has drowned out signals from my body that I needed to rest.

    I’ve been using HRV monitoring for about 18 months, and it’s been tremendously helpful. It’s helped me begin to associate how I FEEL with what the data says — and since I started using this information to shape my training week/month, I’ve gained muscle and lost body fat.

    I’m so excited to see PrimalBeat! Just downloaded the app and will check it out first thing tomorrow morning before I (maybe) hit the gym.

  2. Does this work with any iPhone? I have an iPhone 4 is that too ancient a technology?

    Thanks!

    1. Hi Laura, PrimalBeat HRV works with iPhone. I don’t imagine a problem with an iPhone 4. Maybe you will get some glitches if your ios is old but it should work…

  3. Will this work with a Fitbit charge HR?

    Also, what’s the timeframe on the adroid version?

    thanks!

  4. I’m also wondering if it will work with a fitbit charge HR….seems like a good idea!

  5. …and if you have Windows Phone, well, you’re just plumb out of luck.

      1. Funny! … but in the case of HRV you can still play ball, just look for the other HRV apps that work on windows/android like iThlete.

  6. As a wellness Chiropractor of almost 20 years, I am excited that this technology is being utilized in the fitness world. I have been using this in my practice and in my opinion is one of the best measures of overall health available. It’s much more practical and useable than blood work. Especially when you consider that your nerve system controls and coordinates the function of every other system in the body and if you are in sympathetic dominance there is no way you can achieve health.

  7. im also in the fitbit HR department, from my understanding fitbit already gives you this info. just look at your HR when you wake up (assuming you wear it to sleep). This sure beats wearing a strap when I wake up everyday, and checking checking in with a app other than a band I’m already wearing. unless i’m horribly mistaken 🙂

    1. Does FitBit offer HRV technology? I was not aware of that. You wrote “just look at your HR when you wake up”?? did you mean , “just look at your HRV when you wake up”?? Other sentences got jumbled by siri or some other force so I don’t understand your message completely. Maybe you should walk down the hall and ask the tech guys if FitBit offers HRV, which is distinct from HR as detailed in the post. I would love to know the answer you discover.

      1. they don’t “offer” it as a selling point, but to me it’s the same thing (i think). band is always tracking your heart rate, your daily heart rate is graphed everyday (and logged) in a chart showing the spikes etc through out the day. from what i understand of hrv you “check in” at the same time etc. so when I see a spike in HR when waking up that is out of the usual I go easy or not train at all.

        1. Marlon, HRV =/= HR.
          Heart rate variability seems to be an incredible measure of health. Mark has a number of blog posts on it (linked on this page if you’re curious).

        2. That is to say: variation in daily HR is not the same as Heart Rate Variability.

      2. You are right. I have a Fitbit Surge that I wear most of the time and it does some things but truthfully, it doesn’t do much very well I’m afraid. I’m confident that it cannot offer HRV though. Its HR tracking is erratic in any event and will often show HR 30 – 50 beats per minute away from either chest strap HR tracking or manual count. It’s relatively okay, but still not consistent, when HR increases and decreases slowly and steadily, but it can’t track my heart during a sprint, when I’m skipping or anything that creates fairly dynamic HR responses. Sad but true. And it’s not cheap, either 🙁

  8. I have been checking my HRV since the start of 2015 and it’s been both interesting and helpful. With my HIIT routine, I can see a direct link between a good reading in the morning and the speed of my heart rate recovery between sprints – leading to being able to work harder. I have been using ithlete for Android, but it’s cumbersome because it uses a sensor plugged into the phone jack plus chest strap. More recently I’ve been using Elite HRV for Android with Bluetooth Smart chest strap. I prefer the app plus the strap also works with my workout app, Sportstracker Pro. I still use both HRV apps because I don’t have much historic data from Elite HRV, whereas I have ithlete data going back 8 months.
    I have (once or twice) worked out when my HRV said no – and each time I have finished up with some injuries. So now I take note of what it tells me.
    I can see a general (and slight) fall in HRV for me since June/July this year but can’t be sure of the cause yet. Warmer weather?, added midweek workout from May? Blood donation study that I’m on that takes a donation every 2, instead of the usual (UK) 3 months? Whatever the answer, the information is useful and can be integrated into my planning and the other workout data I get from my other devices – heart rate for workouts, activity tracker for daily stuff like steps, stairs, walks and so on, blood pressure monitor (because I’m not as young as I used to be), and so on.
    But the other thing I have been intrigued by is that the reading doesn’t always match my feeling. I can often feel done it when the HRV reading says ‘go for it’, and it can happen the other way around too. Maybe that will improve with more experience.

    1. well said Steve, keep up the good tracking and training! I believe even with loads of experience, you sometimes have to honor your sub-optimal numbers and back off as it could be a sign of impending trouble, even if you “feel fine” at the present time.

      Now, on the flip side, there is nothing that should override subjective sensations of “diminished desire to train.” If you have diminished desire to train, you don’t train. I love the contribution that Simon Wegerif, founder of iThlete and one of the pioneers of bringing HRV to the mass market, but I strongly object to a statement he offered once to the tune of – if you have a good HRV reading you can go out there and push yourself and hammer, even if you don’t feel like it. That is not just not a sensible strategy. This is a rare occurrence but indeed it can happen. When recovering from a major surgery earlier this summer I delivered some favorable morning RHR and HRV readings despite being too exhausted to walk around the block. Fair warning!

      1. Good response Brad, thanks! I am a psychotherapist and one thing I know for sure is that it is difficult for all of us to separate the instinctive, authentic, voice of our body from our learned/conditional responses. A question I ask is, my body seems to be saying ‘don’t push it today’, but is that my body or my self sabotage talking? Alternatively, my body says ‘go all out today’, but is that my body or my conditioned response to override my inner voice and push past my limits? HRV helps me unpick it 🙂

        1. Thats an awesome couple of questions! Important conundrums to ponder , with no simple answer. I suppose you have to take the first steps and really notice how your are feeling and performing. I can tell by the first sprint of the workout whether I am near 100% or whether I am drag ass. But its often hard to tell before you get out there, get warmed up and start the effort. Especially w high intensity stuff.

          and when HRV is suppressed of course you dont even try so that helps alot

    2. Adding to the above picture a little, Ihave recently taken three weeks away from work and spent two of those in France with my young family and three other friends and their young families. Through the first week away from work, I was at home and expecting to be fairly active and maybe get in some genrous workouts that I don’t usually have the time for. My HRV though, fell daily and said “rest and recover” most of the time. That started about three days into my break. Once I got away to France, I spent most of the time bare foot, had lots of outdoors, sunshine, playing with children, staying up much later than I usually do, eating not as well as I usually do and drinking really more than a little alcohol. HRV throughout, mostly, high and “go get ’em”. Overall activity and movement rates were good, but not crazy high. I was up with children despite having gone to bed at well past midnight, and HRV was generally good.
      All the other adults hadn’t had the benefit of my first week away from work and four out of the other five went down with an unidentified virus or similar for about three days in the first week, so I’m guessing their HRV would have been low.
      Since coming back and trying to return to my usual exercise and activity schedule, I have found that the first week back I seemed to be able to exercise at a high rate every day. I didn’t, but the way my week fell did mean I exercised at pretty high intensity on two consecutive mornings without difficulty and HRV stayed high. Today is half way through the second week since our return and, for the first time, HRV this morning said “rest and recover”. A pitty really, because I was looking forward to my usual early morning mid-week workout.

  9. This would be something I’d normally be interested in. I’ve been taking my resting heart rate daily as a sign of rest. Just need to put my finger to the iPhone camera to measure it – and I think it does fine in determining signs of burn out / stress as I notice jumps in Resting Heart Rate from drinking the night before, etc..

    This app would require a $50-80 overall investment and putting on a strap to measure Resting Heart rate which would already not be fulling resting after all that effort! I’m not into that.

    1. That’s funny Andrey! Your HRV score is low due to the stress of coughing up all that money. Indeed, I’d emphasize that HRV is taking biofeedback to the next level, something that appeals to the most serious and enthusiastic fitness enthusiasts, or others who might be having trouble moderating workplace and life stress. Listen to the PB Podcast with Ronda Collier (search at blog.primalblueprint.com) where she discusses people using deliberate breathing practice to elevate HRV, and how Ronda’s HRV spikes when the phone rings at work and other stress influences happen. It’s definitely superior to just resting HR, because resting HR can be low when you are in a state of adrenal burnout. However, your devotion to monitoring morning resting HR and also using deft intuitive skills to govern exercise decisions and moderate stress in general should be extremely effective.

      1. Hey Brad. I don’t measure HRV – but I don’t think the money is a stress at all, since it’s not a priority. I’m pretty good with intuitively knowing where it makes sense to spend my earnings, and things I can’t really justify buying simply fall off the radar. I’m fairly “enthusiastic” when it comes to fitness – I feel as though I may have come across otherwise. I’m a NASM certified Personal Trainer (although I currently don’t work in the field). I just feel that unless someone is into measuring biofeedback as a hobby OR is a pro-athlete, it’s most likely overkill. I know resting heart rate wont tell the whole story, but for most people it’s enough, along with a bit of that intuitive common sense that Mark often talks about 😉

        I’ll check out the podcast, since I’ve been meditating for a while now. I’ve always been a low-stress person even in high stress situations, but those breathing techniques might be interesting.

        1. oh sorry i misunderstood your comment. You meant that putting on the strap would make you not rested! I thought you meant spending the $ would make you not rested/stressed! You can return to resting heart rate pretty fast after strapping up for sure. thanks for the details.

          For anyone who has struggled with overtraining, burnout, lack of fitness progress, I would argue that getting HRV technology going is not overkill. Its essential. Note the pgh in the post where I was “fooled” by low resting HR in the days after a sprint workout. details in the book Primal Endurance. thanks for your comments

  10. I have been using the Azumio Instant Heart Rate app on Android. No chest strap. You put your finger on the lens. Doctor Ronesh Sinha uses this technology. Maybe not as precise as using a strap but still useful. Dr. Sinha has some videos on heart rate variability too.

    1. Readers, the Azumio app is great but lets be clear and distinguish between measuring heart rate and measuring HRV – heart rate variability. Read the three posts on the topic of HRV to be sure you grasp the nuances

        1. Azumio’s instant heart rate app measures HR, not HRV. Azumio has a different app called “Stress Doctor” which measures HRV using the smartphone flash which is not as accurate as chest strap systems like Sweetbeat, but is better than just checking HR. If you’re using this technology as a way to monitor stress, I would say HR is a very blunt tool which I do use every now and then since it’s quick and easy, HRV using a chest strap is the most accurate (Sweetbeat/Primalbeat) and something like Stress Doctor falls in between. Yes, I do have a couple of posts and videos on my site that provide an elementary explanation of HRV. Just type “HRV” into the search at southasianhealthsolution.org. Look forward to trying out Primalbeat!

  11. Please make a windows phone 10 app as well.
    Especially as they can be easily ported from ios/android, if you don’t want to make a specific windows phone app,

  12. Sometimes when I take a deep breath my heart just stops beating, which is a huge variation.

    I know what you’re thinking and yes, it does start beating again.
    ; )

  13. I measured hrv for a few weeks, and it was always really high, like high 90s to 110ish…didn’t seem to correspond to heavy training days like I thought it would either. At the time I couldn’t find much info about what that might mean, anybody have any similar experiences?

  14. I tried to find the “breathing practices that can elevate HRV”. There only seemed to be one very simple one: inhale/exhale in a 1:2 ratio.

    Really? Is there anything more than that?

  15. Been using Joel Jamieson’s Bioforce HRV for almost 2 years. I’ve also played with iThlete to compare the two.

    I had never been able to consciously relax before, even going through the whole egg chair thing back in college. After two months or so, I think my brain registered that it could affect HRV and my resting heart rate since that happened dropped from around 70 to mid-50s, and HRV came up about 10 points, and stable.

    Some of that is probably sample error, as I can finally listen to what my body is telling me, and days when I wake up and feel like crap, I don’t bother doing the measurement, sleep in a little and change my plan for the day to ensure I’m putting more in the proverbial bucket than I’m taking out.

    Another big learning point was how much more impact sleep and stress had on my HRV than anything I did in the gym. Bar none.

    I prefer the Bioforce, due to the 2:30 sample time. You simply can’t cheat when you have a sample time that long. I could spike my HRV on iThlete, which had a :45 sample time. How long is the sample time for Primalbeat? Also, how long does Primalbeat keep HRV data, and is it backed up to a server so that if you get a new device it keeps the old data? The only issue I have with Bioforce is that if you get a new device you lose the old data. You can get the data from them if you ask, but it won’t update your new device with the information, so you have a loss in trend data.

    I like the guy complaining about cost. At $10, you’re practically giving this away, Mark. I paid $200+ for Bioforce. Joel’s book is the best word-for-word book on training I’ve ever read, though.

    Finally, Azumio did briefly have an HRV app using the iPad/Phone camera. It was complete garbage, but it was cheap. I recommended it to my mom, mostly because it was like $2 and it’d get her to focus on relaxing for a minute a day. Data was worthless though.

    I really like the HRV is gaining momentum. There’s an epidemic of too little sleep and too much stress (well, perception of stress. Bear maulings are stressful, that work deadline is not). HRV won’t lie to you.

    1. Hey Jake the sample time is as long as you want. Sweetwater folks recommend 3 min minimum i think, and 5 min for HF and LF readings to level off. yes you can make an account and back up all your data online. nice comments, keep it up!

  16. Brad, Mark,
    does it work for non-endurance athletes? I am a middle aged office worker, who tries to lift twice a week, and engage in some Martial Arts (usually high intensity) twice a week. Do you think it will still be an effective guide for someone like me as to my training/rest decisions, as it would for the younger triathlete I once was?

    1. Hi PJW, I’d say that you are an example of the kinds of people it works well for. I’ve done a few years without any technology supporting my efforts but have returned to using it and get useful information. Having used HRV since the start of 2015, and me ‘sitting down for a living’ (I’m a psychotherapist) working long days, it helps me plan my workouts and activity, reminds me that there is a more or less immediate physiological outcome from high stress, bad sleep, poor diet and so on. I’m reasonably fit, within my goals (which are long term fit for life rather than athletic performance) and I can track changes over weeks and months. I’m still finding there are days when I feel great but my 2 HRV packages say rest and other days when they say I’m in good shape to workout hard and I ‘feel’ wrong. But that’s part of the benefit of the technology because I have to push past my perceived limits to stress my body for progress and seeing the difference between the various feedback loops is helpful – to me.

    2. HRV monitoring works for anyone with a heart who is interested in tracking stress, recovery, and health. HRV shows if your cardiovascular system is stressed or healthy, and shows the relative balance of your sympathetic to parasympathetic function. listen to the Primal Blueprint podcast with Ronda collier where she talks about using the technology during her office workday, making sure she regulates her breathing to stabilize HRV when annoying people call on the phone or whatever. Good stuff for anyone interested in health and minimizing disease risk factors, and of course essential stuff for serious athletes of any kind.

  17. I started tracking HRV for a little while, but it became just another tech gadget to keep up with that kept me on my phone instead of being out in the woods.

    So I just assume everyday that I need more time in the woods and that I will never match up to the time our ancestors spent out there!

  18. Can the primalbeat HRV measure the HRV from Fitbit HR input? Does measuring HRV require the special straps like Polar H7 mentioned here?

    1. No. You need a chest strap in order to have the accuracy needed to measure the microseconds between heartbeats accurately enough to have acceptable data.

  19. I’m so excited about the HRV app! When my significant other landed in the ER after a Crohn’s flare up we finally found a doctor that supported us managing his symptoms through diet and lifestyle and using HRV to monitor progress, (Duke Integrative Health for those of you in the Durham, NC area). Affordable biofeedback devices are heralding a new stage of individual empowerment that I hope will encourage people to self-experiment rather than blindly accept information fed to them. Can’t wait for some wristbands that are accurate enough to track HRV for continuous monitoring. The chest straps would be a bit awkward under a dress 🙂

  20. Mark, why did you mention the Polar FT4 in your article since it’s not compatible with the PrimalBeat HRV app? I have the FT4 and was so excited about getting the app, which I purchased first thing this morning. But after doing so, I found out the Polar FT4 is not Bluetooth enabled and, therefore, not compatible. I had to purchase the Polar H7 in order to use the app. A little bummed about the additional expense but still really excited about the PrimalBeat HRV app.

    1. I just purchased the Polar FT4 that Mark recommended for the PrimalBeat HRV app. Your right, it is not Bluetooth Smart and will not sync with the app. Guess I’ll return it and try the Polar H7. Rats….

      1. sorry guys, that was my careless research that suggested all Polar’s would work. Im sure you can return something you just bought right?

        1. yes, this same thing happened to me. PLEASE update the article because it has incorrect information still. I now have to return an item (Polar FT4), and reorder costing me time and money. I would recommend that you strongly highlight the BLUETOOTH requirement for the sensor. Polar FT4 is definitely NOT bluetooth compatible.

  21. Any plans to add support for the Apple Watch, if the sensor is adequate?

  22. I have the Zephyr H&M Smart for iPhone I bought almost a year ago that has been working great with PrimalBeat HRV–three days so far. I gave up using it with iThlete when I bought it due to connection issues. I have an iPhone 6.

    1. I think the heart rate was often off with iThlete, too. PrimalBeat looks to be accurate. For example, my resting heart rate with PrimalBeat is always right around 65 but with iThlete I’d get 45, 65, 110, etc. so I could not trust it. I have not tried iThlete in 9 months so perhaps it works better now with app updates.

  23. The article announcing this made it sound like the Polar FT1 would work with this app, which after purchasing the app, I discovered this is not so. You may want to clarify the article.

  24. I agree with Scott above that it would be awesome to have this work with the Apple watch.

  25. An interesting website is http://www.heartattacknew.com which discusses the role of HRV in determining heart attack risk. Basically a weak nervous system increases heart attack risk. I found this website very interesting compared to conventional wisdom’s view of the causes of heart attacks.

  26. Does the PrimalBeat app not have the correlation data like SweetBeatLife? I assumed that it would since they are both made by SweetWater and both cost $9.99, but I do not see the Correlation button in the app. It did have the option to link with MapMyFitness which makes me think that it does have the correlation feature, but I don’t see it. Do I have to turn it on as an option somewhere?

  27. Just got my chest strap and downloaded primalbeat. Is there a tutorial video I can see? Thanks

    Jack

  28. What are the implications on measuring HRV and the efficacy of this app for those with minor heart murmurs?

  29. Any info on whether this will be supported on the Apple Watch now that native apps can tap directly into the sensors?

  30. Mark

    Does your hrv app work with the apple I watch?

    Thanks!

  31. I am so glad Mark has brought HRV to light on his website. I’ve been practicing for over six months now with a product called HeartMath. I absolutely love making a conscious habit each day of becoming still and listening to the “language” of my heart. I am a long distance endurance athlete and, in my transition to leave my burn out and chronic cardio way of life, I have been focusing more on my heart rate variability, rather than heart rate itself. I obtain my HRV using an attachment placed on my earlobe that’s fed to my iPhone. There are different setups available. This company’s mission is to help bring peoples’ physical, mental and emotional systems into coherent alignment with their heart’s intelligent guidance system. A book titled, “Heart Intelligence – Connecting with the Intuitive Guidance of the Heart” by Doc Children and Deborah Rozman, has been enlightening and affirming to read. I would encourage anyone looking to increase their well-being to investigate the benefits of tuning in to their hearts to improve HRV patterns and hence quality of life.

  32. Hey Mark,

    Do you have a specific workout program while monitoring your hrv? I know the types of workouts for parasympathetic and sympathetic practice, but a specific workout plan would be helpful.

    Love your curriculum and website.

    Thanks!
    -Alex

  33. My TomTom chest HR monitor syncs with the app but disconnects before it can get an HRV rating.

    Is there a trick to preventing this from happening? Or does the TomTom HR strap not work well for this style of app?

    Thanks.

  34. I am now using the HRV monitor and I guess I have tons of stress!!! Although I am only a couple days in to regular readings and I am doing it just before lunch… so I guess it isn’t resting HRV – I am also going to record sessions as I work out to see if I can learn a bit more – I am only going to be regular about doing this during the week when I have a steady schedule and have to be inside anyways (Day job) – I am looking to track Heart rate BPM, HRV, speed, time, GPS, Elevation gain, how much I am eating, how much I am sleeping (fit bit app) how much I am lifting for a couple months and see if I can learn more