GPS watch selection in 2016 Fall ~ Built-in heart rate sensor and battery capacity

Built-in heart rate sensor on vivosmart HR

   I will go over some points to select a GPS watch in 2016 fall.


 For hiking

   It is obvious that there are many different GPS watch from many manufacturers, for running and etc.   Each manufacture has a target customer for each model.  Therefore, the selection can be so many.
   I will focus on using it to manage walking pace based on the heart rate in hiking based on some posts in this blog. 


Benefit for built-in heart rate sensor!

   I tested the built-in wrist based heart rate sensor recently.  As a result, I would think it is good enough for hiking.   I think it is a big benefit not to wear the chest strap sensor during hiking.
   There were a couple experience in the past:

• It was easy to move when I shoulder / unshoulder backpack.
• I got some scratch due to the sensor was rubbed during hiking for a long time
• I forgot to bring the chest strap sensor to hiking

   With the built-in sensor we could eliminate them and it is a big benefit in my opinion.
   The other pulse is we can monitor the heart rate 24/7 for most of devices with built-in sensor.  I do not have a good example to have such data.  But there are some interesting data such as heart rate data during sleeping in high altitude something more than 4,000m elevation.  I want to see if there is any indication related the altitude.  

   With those reasons, I prefer to get one with built-in heart rate sensor if I buy a new GPS watch for hiking.

Manufacture selection

   If you already have a GPS watch, I would think you have some tracking data already.  In this case, I guess you want to get one from the same manufacture as your first choice.   However, if you buy it for the first time, you might not have any preference for your selection and you have so many choices from various manufactures.
   In my case, I have been using Gamin GPS products and I do not have much experience to use other manufacture's devices.   Since basic function is almost the same and I do not have any plan to switch the manufacture.   Therefore, I will pick one from Gamin products.   Thus, the selection is very limited. 

Candidates?

   Based on the condition, I will list possible devices from Gamin as of October 2016:

•  vivosmart HR+
• Forerunner 35
• vivoactive HR
• Forerunner 235
• Forerunner 735 XT
• Fenix 3HR

They are the one which has built-in heart rate sensor.

How can we pick one?

   As a next step, how we can narrow down the selection.  First of all, I would think the battery capacity how long we can use the device with GPS mode.  It really depends on how long people typically hike.
   For example, if people usually go hiking up to a few hours in local area.  It might not have much limitation.  People can pick almost any devices since most of them can support the time for cut-off time for full marathon which is usually around 6 hours.
   On the other hand, if people do hiking full day, they need to be careful.   For example, vivosmart HR+ in the list above, it is up to 8 hours with the GPS mode.   This is the time fully charged condition.  Based on my past experience, the time is usually getting short by time being.  If people do a full day hiking, I would think it is better to have more than 10 hours in its specification.  If people consider really long day trip such as a day trip to Mt. Whitney trail.  I think most of people need to take more than 12 hours.  So that it is better to pick a bit longer than 12 hours.  Then, the possible selection would be very limited.

   I my case, I do not think I will do very long day hiking.  Probably the longest is around 10 hours, something like going back to the trail head after summit attempt to Mt. Whitney in Mt. Whitney trail.  For this purpose, I would think more than 12 hours would be good.
    Then, I can eliminate vivosmart HR because it is up to 8 hours in GPS mode.   Forerunner 235 is a border line, it is up to 11 hours.   The rest, Forerunner 35 and vivoactive HR are up to 13 hours, Forerunner 735XT is up to 14 hours and Fenix 3 HR is up to 16 hours.  Forerunner 735XT and Fenix 3 HR can support "ultra-track" mode, which can use up to 24 hours and 40 hours each.

   Just battery capacitor, if people want to have a low cost solution, Forerunner 35 or vivoactive HR would be good.  If people do not have limitation of the price, Forerunner 75XT and Fenix 3 HR could be a good selection.

(To be continue)

GPS Watch selection in 2016 Fall

Forerunner 910XT - It is a little out of date ...

   I am suggesting a pace management based on heart rate during hiking in this blog.   As a part of this topic, I have been using "vivosmart HR" to review the built-in wrist based optical heart rate sensor.   As a conclusion, I would think "vivosmart HR" would be one of good options as a low cost solution.

   On the other hand, I have been running regular bases and try to achieve a personal record for a full marathon.   I also keep hiking records with GPS.  Personally, I really wants to have a GPS watch for those purposes.
   Currently, I have been using "Garmin Forerunner 910XT" for running and hiking GPS tracking.  It is almost 4 years old and I have also been using "vivosmart" /  "vivosmart HR" for daily activity tracking.   It works well and I do not see much problems with those devices.  Recently, I started using "vivosmart HR".  It can monitor not only steps, but also heart rate 24/7.  It is very useful to monitor heart rate 24/7 other than just during hiking.   Especially, I realized that the rest heart rate could be getting higher after hard training and my health condition is not well.   They are a sort of known facts, however with my data, I really recognize the fact more and I can think about my health and training with more attention.

   Originally, I was interested in monitoring heart rate during hiking in higher altitude to see how it looks like.  For the purpose, I was really interested in a device with the built-in wrist based heart rate sensor.   Based on what I have now, which are "vivosmart HR" and "Forerunner 910XT".   I can get all data I want to see with those devices.  However if I look into the latest devices, it can be done with a device.
   It is also getting a lot of improvements for collaborating with a smart phone in last a few years.  We do not have to have PC to manage the data any more.  For a high-end model, we can capture some additional data as well.

   With this given situation, I am thinking to get a new device and there will be so many advantages with the latest device.   I am really interested in what would be options with the latest devices in 2016 fall.  Thus, I will post some considerations.

Garmin heart rate sensor tips!

Chest strap base heart rate sensor

   I have been collecting data to compare the reading offset between Garmin Forerunner 910XT with a chest strap based heart rate sensor and Garmin vivosmart HR with built-in wrist based optical heart rate sensor.  As I posted before, the overall trend is close enough for my usage such as casual running, walking and hiking.  Roughly more than 90% samples are within 4~6 offset.

Chest strap sensor

   As I mentioned in the previous post, I sometimes see inaccurate reading by the chest strap sensor.  In many cases, it shows beginning of a workout.  I also saw a few cases out of twenty workouts after middle of workout.  I think they are probably depends on how I wear the sensor.  Especially the offset in the beginning is probably the sensor might not have a good electrical contact, which might be higher electrical resistance between the sensor and the body.  Once I started sweating, the contact is probably getting better and getting a reasonable reading.  When I saw the offset not in the beginning, I think the sensor could be move / shift during the workout.   I think the chest based sensor is probably good as long as it has good contact to the body in my opinion.  For more accurate measurement, it is probably better to put some moisture when a person wears the sensor.

Wrist based sensor

   First of all, to get a good reading, it seems that we need to wear the device tight enough.  If it is loose, it seems the reading won’t be stable.  This is a similar as the chest based sensor.  The device needs to have a good contact.  Once people understand how tight we need to get the reasonable reading, the result is probably getting better. 

   Based on the past data, I do see two type of inaccurate reading.  One is some higher reading where the heart rate value has a peak.  The maximum heart rate tend to show as higher value than actual.  As long as the reading value is stable and the delta between samples is small, the reading value against the chest sensor is almost matched.

   The other observation is it has some time has a sharp spike.  I do not know why this happens.  But I sometimes see.  The duration is very small and overall heart rete value is stable and no big transition overall.  Just that short period, I do see very high spike.

   Because of those inaccurate reading some time, the maximum heart rate shows higher than the chest based sensor.  I think that is one of reason, Gamin does not offer to estimate VOmax / Lactic threshold by the wrist based sensor.

Conclusion

   Based on the date I collected, the wrist based sensor is totally acceptable for my usage.  People just needs to understand the behavior that it shows a bit higher value sometimes comparing with the chest based sensor.  The both sensor might have error reading, but the chest based sensor reading is much more predictable.  The error reading on the wrist based sensor could be more random and hard to predict in general.   So if the heart rate reading changing a lot, the chance of offsetting could be higher.  As long as the heart rate is stable, it is relatively close to the chest based sensor reading and it is easy to tell if it has some inaccurate reading.

   My opinion, just using the reading value for pacing, the wrist based sensor is all right.   If a workout make higher transition like interval training, it is still useful to use the wrist based sensor, but the chest based sensor can be much stable.  So, I probably continue to use the chest based heart rate sensor for running especially interval and high intensity running.  But I will use the wrist based sensor for hiking and casual running.

   This conclusion is a similar as I concluded in the wrap up for vivosmart HR review.  But with some extra data, I might have a better explanation for the offsetting.

   So far, the wrist based sensor is probably a good option for many people.

Side note:

   The battery life for the broadcast mode is probably around 20 hours.  So it is long enough for tracking the heart rate with broadcast mode to the other device during hiking.

Resting Heart Rate ~ Nice feature to monitor HR 24/7

HR on Garmin Connect Mobile

   It’s been almost a month since I started using vivosmart HR.  Today, I will talk about a feature to monitors my heart rate 24/7.   I used to check my heart rate when I get up in the morning to check my resting heart rate value some time.   Now, I can tell with just checking my heart rate trend on the smart phone.   My smart phone gets the heart rate data from vivosmart HR through Bluetooth.  It is convenient to know my resting heart rate looks like.  My resting heart rate is pretty consistent around 50 bpm.  The maximum heart rate of the day is really depending on what type of training I did.  For the maximum heart rate, if I check the maximum heart rate during a training, I will be able to tell what would be the maximum.

   Based on my data, my heart rate range now could be 50 ~ 175 bpm.   I used to see the maximum heart rate more than 180 bpm a few years ago.  But recently, it becomes something around 175 bpm.  I saw some higher values, but they seem not to be a real data.  They might be some error readings.  My age is now 50 years old.  Based on the common formula, “220 – age” which is 170 bpm.

   I just do a comparison for the heart rate zone definition which is used for heart rate base training.

Zone		With maximum HR		With reserved HR	Notes
		Formula	Actual	Actual
5	90~100%	153~170	158~175	163~175	Sprinting pace
4	80~90%	136~153	140~158	150~163	Fast pace
3	70~80%	119~136	123~140	138~150	Moderate pace
2	60~70%	102~119	105~123	125~138	Comfortable pace
1	50~60%	85~102	88~105	113~125	Relaxed, easy pace

   For my case, there is not much difference between the formula and the actual value if we use a percentage of the maximum heart rate.  However, there is some gap, which is something around 5 ~ 20.   Based on the training contents, I think the percentage of the reserved HR is probably right range in my case and the percentage of the maximum HR is probably much easier side for me.  I am not sure if people can get a similar result for this or not.  But at least my case, it is probably better to start with the percentage of the maximum heart rate with estimate formula.  Once people figure out the maximum and the resting HR, then it could move to the percentage of the reserved heart rate.

   I guess people who is doing regular base training for long time could have a similar.  However, I would think that people who has not been training regular basis and just starts training might have different trend.