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HIIT Defined - What is (or isn't) HIIT?

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  • MikePfirrman
    MikePfirrman Posts: 3,307 Member
    edited July 2019
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    CSARdiver wrote: »
    Phirrgus wrote: »
    CSARdiver wrote: »
    Phirrgus wrote: »
    CSARdiver wrote: »
    Phirrgus wrote: »
    heybales wrote: »
    Phirrgus wrote: »
    For what it's worth, I'm 55 and my best guess is my max HR is around 194 right now.

    I'm 51, and my "predicted" max heart rate (220 minus my age) is 169, which seems about right to me. The highest HR I've ever observed in a workout is about 165.

    If you're 55 and your max HR is about 194, you're obviously in much better shape than me, or you've been an endurance athlete for much of your life!

    Whatever the case, that's awesome. :)

    That formula seems to work for me as well. 59 (for a few more weeks lol) and hitting the bike as hard as I can gets me about 160 for a HR. That's a watch though, not a chest strap.

    And yeah, he's being modest about but @MikePfirrman got some serious CV health going on. Making me want to invest in a C2.

    I've found very few that find accuracy with wrist-HR when it starts going higher - I'll bet your maxHR reached on those workouts is higher.
    It sure feels higher lol. Piqued my curiosity, and I've been leaning more towards cardio so I may invest in a strap. Thanks for the FYI :)

    I highly recommend the Polar H7. I've been tracking data since the 90s and most chest recorders are close to medical accuracy. While it may feel like a nuisance initially you hardly know it is there after a few workouts.

    @CSARdiver thanks for the recommendation. Just browsing for a few minutes I see the Polar getting high marks, so I think I may roll with that. No straps seems to sync with fitbit, but they both sync with mfp, so I ought to be able to get some good data off that. Thank you sir

    The only drawback with the H7 is that it requires a smartphone, so you can't simply look at your wrist and check data. The premium app package is ~20 USD I think and enables you to a whole suite of algorithms and calculations. You can upload this data to Polar Flow https://flow.polar.com/ and monitor you data over time.

    The other nice thing is that is a relatively small investment in comparison to the other devices.

    I was just reading up on the H10, which will store one workout in memory. The extra ~$30 might be worth being able to leave my phablet (note 8) at home. My doc is also a stickler for HR data, so that premium package may well be worth it too.

    Really appreciate the tips. :) New toys, especially useful ones are always nice.

    Nice! Was not even aware of the H10. Looks like a solid unit.

    Note - My H7 is almost 5 years old and I use this swimming, biking, and running primarily and have had no issues.

    I had the opposite experience with the H7. Very sporadic and only lasted around 2 months. When the battery died, it died. I had high hopes for it too, loved my old Polar wrist monitor (F4??) with HR strap. Those were the best.

    I have heard good things, though, about the H10. Also the Wahoo Tickr.

    I just bought a Coospo HRM. It's the cheap, made in China version of the H10. It was $32 (edited, it's $38) and allegedly, it's waterproof too. I'm a terrible swimmer, so I'd never test in water! Now, I had to get a phone app to work with it but it integrates seemlessly with my C2, so at least so far, I like it. But I've only had it three weeks or so. Very responsive. It's a cheaper version of the H10 or the Wahoo Tickr X, which run much higher.
  • heybales
    heybales Posts: 18,842 Member
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    Funny, logged into my ancient Polar account finally, and got this notice from June:
    "Team Polar Calling all crossfitters and plyo fans! We have recently renamed two of our sport options available in Flow: - Crossfit is now High-intensity interval training (HIIT)"
  • robertw486
    robertw486 Posts: 2,390 Member
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    heybales wrote: »
    Ditto to HRmax genetics, but being fit as you age sure seems to prevent the normal rate of lowering that occurs.
    191 (from 194) last I tested at age 49.
    But some people just have a low diesel heart with lower HRmax.

    I think the HR graphs being shown are good too for showing that when you do max for briefer amounts of time, you can sometimes keep it up, but the total "set" time is still not that long. If either starts lengthening, the ability to keep it high drops.

    This is from HIIT and SIT workout I enjoy doing from time to time, though it's been awhile at this point.

    The HIIT is 15 sec sprint, 45 walk. The SIT is 1 min sprint (which is attempted at level pace but all I got), 1 min walk.
    20 min gentle jog in the middle for recovery.

    5pbmbsyypdof.png

    25824xh5ikja.png

    As was mentioned about trying to think during this - I have the Garmin kicking off the buzzers so I only have to hear that. Math would be interesting.
    I think the reason why I can't get the HR up towards max better is running wasn't my main thing, though the 194 was based on running test.
    But that's the other nice thing about HIIT - all out is level of effort, pretty easy to hit. Get it, hiit, never mind.

    It would be interesting to see you (and others) actually use one of the activities and do some HIIT set to IE1 protocol. I would think the easiest activities would be power meter equipped bikes, meter equipped rowers, and the use of a treadmill.... though I think the latter would be rather risky similar to my use of the elliptical.

    I think people would be surprised myself, as I know I was. The 170% max is not as crazy hard as I was expecting. With the super short break it gets really hard going into the last intervals for sure. But with a longer rest I think most people could do more than the 7-8 they use in the Tabata IE1 method.


    As for math... fuggetaboutit. When I decided to try the IE1 on my elliptical, I failed to think about the delay feature. The machine will log data for 6 seconds after you stop. I ended up finding a beep timer app, and all I had to do was listen to the instructions of the beeps.

    I usually love having all that data in front of me. Doing Tabata... nope, nope, nope. It was bad enough that I had to use the lesser desired stride rate output to gauge my 170%. For some reason the calories per minute output stops at 25 and then wraps around bad to 0.
  • heybales
    heybales Posts: 18,842 Member
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    I really do want to attempt the correct protocol, after getting an updating VO2max estimate to hit the right level.

    Wish I had access to these gym treadmills one of the trainers gave me the trainer password to - you could set up your own interval session with change of pace, incline, for time or HR, very cool. It still had a lag time to increase the pace or incline, but a whole lot easier than trying to bunch up/down buttons when sprinting.

    I hate using my bike on a trainer wheel I have, can't really stand to crank it up fast. I wonder how they adjusted so fast in the study? Probably had trainer bikes like the treadmills I liked using, programming ability.
  • NorthCascades
    NorthCascades Posts: 10,968 Member
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    robertw486 wrote: »
    Since this seems to be an item often debated in other areas, I thought we should open it up for debate. Hopefully it will help others define what they believe is or isn't HIIT, and the possible benefits or lack thereof of using HIIT as part of a workout program.


    Firstly, I'm going to quote what the ACSM literature defines as HIIT

    "This type of training involves repeated bouts of high intensity effort followed by varied recovery times. The intense work periods may range from 5 seconds to 8 minutes long, and are performed at 80% to 95% of a person’s estimated maximal heart rate, the maximum number of times your heart will beat in a minute without overexerting yourself. The recovery periods may last equally as long as the work periods and are usually performed at 40% to 50% of a person’s estimated maximal heart rate. The workout continues with the alternating work and relief periods totaling 20 to 60 minutes."

    The above taken from This link https://acsm.org/docs/brochures/high-intensity-interval-training.pdf

    I've used the ACSM definition for one primary reason. It's the only clearly defined view given by any professional organization that I have come across. Feel free to add any other definitions that are linked to health or fitness organizations, credible fitness professionals, or institutions. Let's just try to avoid what Billy Jim Bob thinks is HIIT, as we could all come up with something if we wanted. Limiting the definitions to professional levels rather than a fitness blog might help sort out fact based vs trendy buzzword sales pitches.

    Per the ASCM literature, HIIT training can be up to an hour. The major basis they seem to use is a percentage of a max heart rate. Since this ties in to VO2max and oxygen uptake, it seems a valid gauge of effort to me. As for duration, I would consider an hour of anything to be taxing if an all out effort, and the interval and rest periods lessen the work time, so once again I would consider it a high intensity. As a note, I would suspect that many people could sustain an effort above VO2max for an hour if they used a 50/50 split of work vs recovery time. And I think many of us could agree that any effort above VO2max is a high intensity. And at the end of the day, it seems a fair enough gauge to me to accept HIIT as ACSM defines it. I do intervals from sub VO2max levels up to much higher levels, and it really won't bother me what others do or don't consider to be HIIT levels.


    What do you consider HIIT, or what would disqualify a routine as HIIT? What studies, organizations, or professionals led you to this definition? Is is possibly to do HIIT at efforts below VO2max or does it require an effort into anaerobic range? Is the best gauge HR, HRR, VO2max, time vs perceived effort, or something else? What measures of power do you need to qualify something as HIIT, if any? How long could a person do do HIIT? When is it just intervals (or intermittent per Tabata) and when is it HIIT? Give an example of something you consider HIIT (or not), and qualify your statements.



    I'm going to start with something easy to qualify as HIIT: Tabata IE1 protocol

    Why? It seems to be one of the modern day routines accepted as HIIT, and is of an intensity high enough that few would dispute it is high intensity. Based on an output of 170% of VO2max, it's good that the work interval is only 20 seconds. However, the very brief rest period of 10 seconds ensures that if you reach that 7th or 8th interval, you will be at an oxygen deficit and breathing hard. Numerous studies have accepted it as HIIT, as well as documented both aerobic and anaerobic benefits. I'd say that anyone that doesn't get their heart rate well into the zones accepted by the ACSM is probably someone with a heart issue or just straight out superhuman. The highest heart rate I've ever recorded myself was doing Tabata IE1 on our elliptical machine.

    Would I want to do it long term or often? I don't know really. Some time back I did a week of the protocol just for "fun" and lack of time on my hands. It wasn't as terrible as I thought it might be, but mixing it up is usually more fun for me personally. I'm usually somewhat a glutton for the punishment of high output efforts and pushes, but it left me feeling like I was so focused on the output between my timer beeps that I didn't really have any time to enjoy or dislike the workout much.

    It would likely have been much more "enjoyable" on a bike. Due to the output level, probably a very high risk of injury on many machines and/or exercises. It was tricky on an elliptical. Maybe possible with uphill sprints, but unless you have Usain Bolt levels of speed, I'd suspect very hard to do on the flat when sprinting.


    Maybe if we can form some agreement on where people draw the line of what is included in HIIT, we could move on to why (or why not) people might choose to use it as part of their exercise programs. It seems that HIIT is the trend now, and helping others figure out the actual studies and basis for use vs what a local trainer is selling might help some people out.

    Heart rate lags by about 45 seconds. It's useless for titrating a 5 second effort. I don't think that definition is very good.
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    Options
    CSARdiver wrote: »
    Phirrgus wrote: »
    CSARdiver wrote: »
    Phirrgus wrote: »
    heybales wrote: »
    Phirrgus wrote: »
    For what it's worth, I'm 55 and my best guess is my max HR is around 194 right now.

    I'm 51, and my "predicted" max heart rate (220 minus my age) is 169, which seems about right to me. The highest HR I've ever observed in a workout is about 165.

    If you're 55 and your max HR is about 194, you're obviously in much better shape than me, or you've been an endurance athlete for much of your life!

    Whatever the case, that's awesome. :)

    That formula seems to work for me as well. 59 (for a few more weeks lol) and hitting the bike as hard as I can gets me about 160 for a HR. That's a watch though, not a chest strap.

    And yeah, he's being modest about but @MikePfirrman got some serious CV health going on. Making me want to invest in a C2.

    I've found very few that find accuracy with wrist-HR when it starts going higher - I'll bet your maxHR reached on those workouts is higher.
    It sure feels higher lol. Piqued my curiosity, and I've been leaning more towards cardio so I may invest in a strap. Thanks for the FYI :)

    I highly recommend the Polar H7. I've been tracking data since the 90s and most chest recorders are close to medical accuracy. While it may feel like a nuisance initially you hardly know it is there after a few workouts.

    @CSARdiver thanks for the recommendation. Just browsing for a few minutes I see the Polar getting high marks, so I think I may roll with that. No straps seems to sync with fitbit, but they both sync with mfp, so I ought to be able to get some good data off that. Thank you sir

    The only drawback with the H7 is that it requires a smartphone, so you can't simply look at your wrist and check data. The premium app package is ~20 USD I think and enables you to a whole suite of algorithms and calculations. You can upload this data to Polar Flow https://flow.polar.com/ and monitor you data over time.

    The other nice thing is that is a relatively small investment in comparison to the other devices.

    For what it's worth, newer Garmin watches can talk to Bluetooth heart rate sensors. I think Suunto watches have had that ability for years, and I think Polar makes some too. If you don't have one it's $$$, but if being able to see your HR in real time on your wrist is important, you can do that.
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    Options
    CSARdiver wrote: »
    Phirrgus wrote: »
    CSARdiver wrote: »
    Phirrgus wrote: »
    CSARdiver wrote: »
    Phirrgus wrote: »
    heybales wrote: »
    Phirrgus wrote: »
    For what it's worth, I'm 55 and my best guess is my max HR is around 194 right now.

    I'm 51, and my "predicted" max heart rate (220 minus my age) is 169, which seems about right to me. The highest HR I've ever observed in a workout is about 165.

    If you're 55 and your max HR is about 194, you're obviously in much better shape than me, or you've been an endurance athlete for much of your life!

    Whatever the case, that's awesome. :)

    That formula seems to work for me as well. 59 (for a few more weeks lol) and hitting the bike as hard as I can gets me about 160 for a HR. That's a watch though, not a chest strap.

    And yeah, he's being modest about but @MikePfirrman got some serious CV health going on. Making me want to invest in a C2.

    I've found very few that find accuracy with wrist-HR when it starts going higher - I'll bet your maxHR reached on those workouts is higher.
    It sure feels higher lol. Piqued my curiosity, and I've been leaning more towards cardio so I may invest in a strap. Thanks for the FYI :)

    I highly recommend the Polar H7. I've been tracking data since the 90s and most chest recorders are close to medical accuracy. While it may feel like a nuisance initially you hardly know it is there after a few workouts.

    @CSARdiver thanks for the recommendation. Just browsing for a few minutes I see the Polar getting high marks, so I think I may roll with that. No straps seems to sync with fitbit, but they both sync with mfp, so I ought to be able to get some good data off that. Thank you sir

    The only drawback with the H7 is that it requires a smartphone, so you can't simply look at your wrist and check data. The premium app package is ~20 USD I think and enables you to a whole suite of algorithms and calculations. You can upload this data to Polar Flow https://flow.polar.com/ and monitor you data over time.

    The other nice thing is that is a relatively small investment in comparison to the other devices.

    I was just reading up on the H10, which will store one workout in memory. The extra ~$30 might be worth being able to leave my phablet (note 8) at home. My doc is also a stickler for HR data, so that premium package may well be worth it too.

    Really appreciate the tips. :) New toys, especially useful ones are always nice.

    Nice! Was not even aware of the H10. Looks like a solid unit.

    Note - My H7 is almost 5 years old and I use this swimming, biking, and running primarily and have had no issues.

    I had the opposite experience with the H7. Very sporadic and only lasted around 2 months. When the battery died, it died. I had high hopes for it too, loved my old Polar wrist monitor (F4??) with HR strap. Those were the best.

    I have heard good things, though, about the H10. Also the Wahoo Tickr.

    I just bought a Coospo HRM. It's the cheap, made in China version of the H10. It was $32 (edited, it's $38) and allegedly, it's waterproof too. I'm a terrible swimmer, so I'd never test in water! Now, I had to get a phone app to work with it but it integrates seemlessly with my C2, so at least so far, I like it. But I've only had it three weeks or so. Very responsive. It's a cheaper version of the H10 or the Wahoo Tickr X, which run much higher.

    Mine arrived in the mail today. Two rides on it so far (I work from home, lunch rides are great). My Garmin connects to it over BT instead of ANT+ which is new to me.

    The signal can't travel through (more than about 3 cm of) water, so it won't be of much use swimming. There are chest straps meant to be used in the water which store the HR data and forward it to your computer when you get out of the water. They also tend to be tacky to hold tight to your chest while you swim, really uncomfortable in any other context.
  • robertw486
    robertw486 Posts: 2,390 Member
    Options
    heybales wrote: »
    I really do want to attempt the correct protocol, after getting an updating VO2max estimate to hit the right level.

    Wish I had access to these gym treadmills one of the trainers gave me the trainer password to - you could set up your own interval session with change of pace, incline, for time or HR, very cool. It still had a lag time to increase the pace or incline, but a whole lot easier than trying to bunch up/down buttons when sprinting.

    I hate using my bike on a trainer wheel I have, can't really stand to crank it up fast. I wonder how they adjusted so fast in the study? Probably had trainer bikes like the treadmills I liked using, programming ability.

    It wasn't fun on an elliptical, and I doubt it would be fun unless on a sturdy trainer. I'm not sure how they ramped up output so quick during their tests, but it was next to impossible on the elliptical. I had to just accelerate hard at a set ramp and resistance and make wattage through leg speed.
  • robertw486
    robertw486 Posts: 2,390 Member
    Options
    robertw486 wrote: »
    Since this seems to be an item often debated in other areas, I thought we should open it up for debate. Hopefully it will help others define what they believe is or isn't HIIT, and the possible benefits or lack thereof of using HIIT as part of a workout program.


    Firstly, I'm going to quote what the ACSM literature defines as HIIT

    "This type of training involves repeated bouts of high intensity effort followed by varied recovery times. The intense work periods may range from 5 seconds to 8 minutes long, and are performed at 80% to 95% of a person’s estimated maximal heart rate, the maximum number of times your heart will beat in a minute without overexerting yourself. The recovery periods may last equally as long as the work periods and are usually performed at 40% to 50% of a person’s estimated maximal heart rate. The workout continues with the alternating work and relief periods totaling 20 to 60 minutes."

    The above taken from This link https://acsm.org/docs/brochures/high-intensity-interval-training.pdf

    I've used the ACSM definition for one primary reason. It's the only clearly defined view given by any professional organization that I have come across. Feel free to add any other definitions that are linked to health or fitness organizations, credible fitness professionals, or institutions. Let's just try to avoid what Billy Jim Bob thinks is HIIT, as we could all come up with something if we wanted. Limiting the definitions to professional levels rather than a fitness blog might help sort out fact based vs trendy buzzword sales pitches.

    Per the ASCM literature, HIIT training can be up to an hour. The major basis they seem to use is a percentage of a max heart rate. Since this ties in to VO2max and oxygen uptake, it seems a valid gauge of effort to me. As for duration, I would consider an hour of anything to be taxing if an all out effort, and the interval and rest periods lessen the work time, so once again I would consider it a high intensity. As a note, I would suspect that many people could sustain an effort above VO2max for an hour if they used a 50/50 split of work vs recovery time. And I think many of us could agree that any effort above VO2max is a high intensity. And at the end of the day, it seems a fair enough gauge to me to accept HIIT as ACSM defines it. I do intervals from sub VO2max levels up to much higher levels, and it really won't bother me what others do or don't consider to be HIIT levels.


    What do you consider HIIT, or what would disqualify a routine as HIIT? What studies, organizations, or professionals led you to this definition? Is is possibly to do HIIT at efforts below VO2max or does it require an effort into anaerobic range? Is the best gauge HR, HRR, VO2max, time vs perceived effort, or something else? What measures of power do you need to qualify something as HIIT, if any? How long could a person do do HIIT? When is it just intervals (or intermittent per Tabata) and when is it HIIT? Give an example of something you consider HIIT (or not), and qualify your statements.



    I'm going to start with something easy to qualify as HIIT: Tabata IE1 protocol

    Why? It seems to be one of the modern day routines accepted as HIIT, and is of an intensity high enough that few would dispute it is high intensity. Based on an output of 170% of VO2max, it's good that the work interval is only 20 seconds. However, the very brief rest period of 10 seconds ensures that if you reach that 7th or 8th interval, you will be at an oxygen deficit and breathing hard. Numerous studies have accepted it as HIIT, as well as documented both aerobic and anaerobic benefits. I'd say that anyone that doesn't get their heart rate well into the zones accepted by the ACSM is probably someone with a heart issue or just straight out superhuman. The highest heart rate I've ever recorded myself was doing Tabata IE1 on our elliptical machine.

    Would I want to do it long term or often? I don't know really. Some time back I did a week of the protocol just for "fun" and lack of time on my hands. It wasn't as terrible as I thought it might be, but mixing it up is usually more fun for me personally. I'm usually somewhat a glutton for the punishment of high output efforts and pushes, but it left me feeling like I was so focused on the output between my timer beeps that I didn't really have any time to enjoy or dislike the workout much.

    It would likely have been much more "enjoyable" on a bike. Due to the output level, probably a very high risk of injury on many machines and/or exercises. It was tricky on an elliptical. Maybe possible with uphill sprints, but unless you have Usain Bolt levels of speed, I'd suspect very hard to do on the flat when sprinting.


    Maybe if we can form some agreement on where people draw the line of what is included in HIIT, we could move on to why (or why not) people might choose to use it as part of their exercise programs. It seems that HIIT is the trend now, and helping others figure out the actual studies and basis for use vs what a local trainer is selling might help some people out.

    Heart rate lags by about 45 seconds. It's useless for titrating a 5 second effort. I don't think that definition is very good.

    I'd agree on the heart rate point for anything short. But if you did 5 second intervals so hard your HR was up to 80%+ of a persons max heart rate, the work would have to be really hard. I reached my highest recorded HR doing IE1, and that only has a little over two minutes work time. I did average over 170% on that round, but the HR rise is real.
  • NorthCascades
    NorthCascades Posts: 10,968 Member
    Options
    CSARdiver wrote: »
    Phirrgus wrote: »
    CSARdiver wrote: »
    Phirrgus wrote: »
    CSARdiver wrote: »
    Phirrgus wrote: »
    heybales wrote: »
    Phirrgus wrote: »
    For what it's worth, I'm 55 and my best guess is my max HR is around 194 right now.

    I'm 51, and my "predicted" max heart rate (220 minus my age) is 169, which seems about right to me. The highest HR I've ever observed in a workout is about 165.

    If you're 55 and your max HR is about 194, you're obviously in much better shape than me, or you've been an endurance athlete for much of your life!

    Whatever the case, that's awesome. :)

    That formula seems to work for me as well. 59 (for a few more weeks lol) and hitting the bike as hard as I can gets me about 160 for a HR. That's a watch though, not a chest strap.

    And yeah, he's being modest about but @MikePfirrman got some serious CV health going on. Making me want to invest in a C2.

    I've found very few that find accuracy with wrist-HR when it starts going higher - I'll bet your maxHR reached on those workouts is higher.
    It sure feels higher lol. Piqued my curiosity, and I've been leaning more towards cardio so I may invest in a strap. Thanks for the FYI :)

    I highly recommend the Polar H7. I've been tracking data since the 90s and most chest recorders are close to medical accuracy. While it may feel like a nuisance initially you hardly know it is there after a few workouts.

    @CSARdiver thanks for the recommendation. Just browsing for a few minutes I see the Polar getting high marks, so I think I may roll with that. No straps seems to sync with fitbit, but they both sync with mfp, so I ought to be able to get some good data off that. Thank you sir

    The only drawback with the H7 is that it requires a smartphone, so you can't simply look at your wrist and check data. The premium app package is ~20 USD I think and enables you to a whole suite of algorithms and calculations. You can upload this data to Polar Flow https://flow.polar.com/ and monitor you data over time.

    The other nice thing is that is a relatively small investment in comparison to the other devices.

    I was just reading up on the H10, which will store one workout in memory. The extra ~$30 might be worth being able to leave my phablet (note 8) at home. My doc is also a stickler for HR data, so that premium package may well be worth it too.

    Really appreciate the tips. :) New toys, especially useful ones are always nice.

    Nice! Was not even aware of the H10. Looks like a solid unit.

    Note - My H7 is almost 5 years old and I use this swimming, biking, and running primarily and have had no issues.

    I had the opposite experience with the H7. Very sporadic and only lasted around 2 months. When the battery died, it died. I had high hopes for it too, loved my old Polar wrist monitor (F4??) with HR strap. Those were the best.

    I have heard good things, though, about the H10. Also the Wahoo Tickr.

    I just bought a Coospo HRM. It's the cheap, made in China version of the H10. It was $32 (edited, it's $38) and allegedly, it's waterproof too. I'm a terrible swimmer, so I'd never test in water! Now, I had to get a phone app to work with it but it integrates seemlessly with my C2, so at least so far, I like it. But I've only had it three weeks or so. Very responsive. It's a cheaper version of the H10 or the Wahoo Tickr X, which run much higher.

    I learned something about this since my last post, not sure if it matters or not but I'll throw it out there.

    My Garmin prefers to connect to the strap over BT instead of ANT+. Every time. A friend's Bolt does too. I don't know if it matters for data quality, ANT+ uses a little less power though so your computer lasts longer.

    Anyway if you prefer using ANT+, connect your phone to the strap first. BT only allows one connection.