Example to for VO2max estimation in Garmin Running device

最近の最大酸素摂取量の推移

　今日の話題は、ガーミン社のランニング用のデバイスの活用方法の紹介の続きです。以前から私の利用法について投稿していますが、今日は、最近のガーミン社のランニング用のモデルではついている物が多くなった最大酸素摂取量（VO2max）の推定機能についてです。

最大酸素摂取量

　最大酸素摂取量は有酸素運動のパフォーマンスの指標として用いられる値の一つで、厳密な測定では、トレッドミルで負荷を増加しながら呼吸量、酸素量、二酸化炭素量を測定する事が必要です。ただし、簡易的に行われる物として、クーパーテスト（12分間走）などでも推定値を知る事ができるとされています。最近のランニング用のデバイスではこうした推定値を各アクティビティのデータを基に推定する機能がついています。

　以前にも紹介していますが、fenix 3 HRにもその機能がサポートされていて、実際に行ったアクティビティのデータで概算の最大酸素摂取量を推定してくれます。今回、故障や風などでトレーニングができない期間がこの数か月の間に何回かあったので、その影響がこの値にどのように影響するかを知る事ができたのでその結果を投稿する事にしました。

過去5ヶ月のデータ

　冒頭のグラフが過去5ヶ月の私の最大酸素摂取量の推移です。4月の43[ml/kg/min]をピークに下降傾向というのがわかります。この期間のトレーニング状況ですが、4月はガーミン社のトレーニングプラン、フルマラソンのレベル２を終了した直後で、トレーニングの効果もあり、VO2maxの値が徐々に改善し、最近の最高値に達していました。ところが、4月の下旬に左足を負傷して、約1ヶ月の間トレーニングを休むことになってしまいました。その後トレーニングを2週間ほど再開した後、6月に入って風邪をひいてしまい、さらに3週間トレーニングを休んだために38[ml/kg/min]まで低下してしまいました。7月はトレーニングを再開して、40[ml/kg/min]まで回復しましたが、日本に行っていた約1週間の間トレーニングを休んだためまた、38[ml/kg/min]に戻ってしまいました。その後8月はトレーニングを再開しましたが、今回は急にトレーニングを再開した事による負傷を防ぐために、トレーニングプランをフルマラソンのレベル１に戻って再開したため、トレーニング初期段階の負荷が軽くなった事もあってまだ改善が見られていません。ここ数日は体調を崩してペースが上がらないため、値はやや下降気味になっているというのが最近のトレーニング状況です。

データの考察

　この結果を見ると、トレーニング状況とその負荷が値に大きく影響していると見る事ができるかと思います。特に改善のスピードは緩やかですが、下降は少しトレーニングを休んだり、負荷を落とすとすぐに値が落ちてしまう様です。

　7月は約1日おきにマラソンペース（心拍ゾーンのレベル３）で5kmから始めて10kmまで徐々に距離を延ばすのを約1ヶ月続けたところ、ある程度の改善がありましたが、8月に再開した際は、フルマラソン　レベル１の最初の部分で比較的負荷も軽く、週3回の実施と言うことで、7月に比べてトレーニング頻度が落ちている事もあって、改善の度合いは殆どmられていません。

　このデータを見ると、VO2maxの値は、トレーニング状況が比較的すぐに数値として表れるようで、トレーニングの状況を見るのには都合の良い値だと考える事ができます。今後は、トレーニングプランの負荷が徐々に上がって来ると思うのでそれがどの様に値に影響してくるかがポイントになるかと思います。

　クーパーテストを行うのもVO2maxを知る手法になると思いますが、こうした値を推定できる機能がデバイスについて、普段のトレーニングから値を推定してくれるのはより手軽に指標を得られる事になるのでとても便利な機能だと思います。この機能のためだけでも、デバイスをアップグレードするメリットはあると思います。

Trekking Pole

Trekking Pole and Pole for skiing

   It is September now.  I have been busy this summer for many unexpected things.  New school year started for our kids in mid August and it is back to normal now and finally I have some spare time to write an article.

   Today's topic is "Trekking Poles" that many hikers are using nowadays at least in the US.   I did not use them when I was young.  But I started using them a few years ago since I am getting old and I'd probably better to get some support using them.   I was using one for skiing, but it was broken and I bought a pair of trekking poles last year.

Trekking Poles

What I bought was one from Black Diamond, you can find it in Amazon.  There are many different types, this is a folding type  Another type is an adjustable type, which is easy to adjust the length.  Most of folding type is fixed length, but one I bought was there is a part to adjust the length on the top part.

Adjustable part

   This is a model for women, I think the main difference is strength and weight.  I think it is good enough for my weight.  I am relatively smaller than typical men.
　
   A difference between trekking poles and ski poles are the tip portion.
　

Tip portion for a skiing pole

   Tip portion for skiing is designed easy to stick surface of snow with metal tip.  It is also having larger ring not sinking into the snow.

Tip for a trekking pole

   On the other hand, trekking pole is using rubber material to get more friction on rocks.  The ling is smaller or nothing.  This model can replace the tip to a metal part to use on the snow.

Metal tip for replacement

   Some models, it is also possible to replace the ring to use for skiing.  However, I have different poles for each purpose.  The model i have, it is ok to use on a snow course in summer time.  But for skiing the ling is too small and sinking into the snow when I use them for skiing.  Also, the length on the tip portion is too short to use for skiing as well.
　The tip has many different shapes.  Some of them are bigger tip to get more friction and stable on rocks.

   As I mentioned, I was using poles for skiing in my previous hiking.  However, the stress to the big ring is big on summer trail.  Also, the friction might be smaller and not very stable.   However, the friction is not a big deal, just need to have some experience to adjust how we use it.

Advantage to use trekking poles

   Talking about advantage using trekking poles, the major advantage is helping to keep the balance.  Using poles, the chance to loose the balance is probably getting less, it is also easy to recover when people loose their balance with the poles.  In general, many people select boots to protect their ankles.  However if people using poles they may choose lighter pair and the selection is more flexible.  Especially having heavy backpack, people tend to pick really heavy boots for a better protection.   With the poles, they may pick liter boots.  Also, if they do not have heavy backpack, they may pick shoes instead of boots.  It is really depending on strength of legs, experience and skill to pick shoes / boots.  I would say with combination with trekking poles, the selection will be more flexible and easier for many people.

   In my case, my leg strength is getting weaker than when I was young.  It is really helpful to distribute weight with pole to reduce weight to legs.   That is the primary reason I started using poles.
   I think many people using a pair of pole on the both hand.  I guess it might be better to keep balance during hiking.   However, I personally do not like to occupy the both hands, therefore, I just using a single pole to help the balance.

Low cost models?

   By the way, when I am looking into listing on Amazon, there are many low cost models.   Most of time, I usually go to outdoor stores to see one I want to buy.  Therefore, I do not see many low cost model in the stores.  However, some of friends mentioned that there are many low cost models and I realize there are so many low cost models.
   For example, this model  is USD $36.99.  I have never used them and I cannot tell what they look.  Just based on the specification, its pair of weight is 1.1(lb).  One the other hand one I bought is 1.6(lb).  It is about a 0.25(lb) difference.   It is probably some difference for the material and strength.  I do not have any experience to use them, so this is just my speculation.   I guess it is not a big problem in most of cases.  Probably, it might be easy to broken or deform when they get unexpected force during hiking.  So this is really up to how people think and use them.

  Personally trekking poles are probably one of good equipment for middle age to older age hikers to minimize injury during the hiking.

Good time for hiking ~ Minimize impact of high altitude sickness during hiking

Yosemite National Park (July/2016)

   It is mid July and this is a good time for hiking.   Kids started summer vacation in the United States.  I think many people plans to go hiking this summer.
   I keep posting about a method to manage hiking pace based on heart rate with a running watch, activity trackers.   Finally, I published a kindle book last April in Japanese.  I have been working on its English edition now.  This book is based on my past data for Mt. Whitney hiking.  Mt. Whitney is very popular destination for hiking in California.  (Japanese Edition -- High Tech pace management)
  There are some mountains over 12,000 feet, that many people easily hike, such as Mt. Whitney, White mountain, Mt. Dana (which is in the photo in this posting.  If you have a GPS tracking data with heart rate, please share your data for my further study.

   As I mentioned, I am working on the English edition, but it will take some time.  Therefore, I introduce a simple method in this positing.  Please try this if you hike high elevation.

1. Estimate your maximum heart rate from your age
   A popular formula to estimate the maximum heart rate by age is "220 - (age)".  As an example, I am 50 years old and my estimated value is "220 - 50 = 170".  So that my value is 170 (bpm).  This value may not be very accurate.  Since the maximum heart rate depends on each person depending on the fitness and regular training situation.  However, this value could be a good enough as a placeholder or starting point.  (This is not a generic,  this is based on my past data)

 2. Calculate heart rate zone
   The next step is to calculate heart rate zone with a spreadsheet software like MS-Excel.   The calculation is to get heart rate number in 50% ~ 100% of the maximum heart rate by 10% step, which is 50%, 60%, 70%, 80%, 90% and 100%.  They are used to define each heart rate zone, the zone 1 is 50~60% range and zone 5 is 90 _ 100%.   The following is an example of my case.

Example of heart rate zones

3. A guide line of walking pace during hiking.
   Based on my experience, we need to stay in zone 3 which is 70~80% of the maximum heart rate or lower.  In my case, 119 (bpm) ~ 136 (bpm) or lower.

4. Heart rate monitor
   People can use an activity tracker, running watch with GPS, Apple watch to monitor your heart rate during hiking.   One for running, it usually has a feature to notify with alarm or vibration if the heart rate is out of a range people set.  This is really convenient feature to manage the walking pace during hiking.

5. When the heart rate is out of range, it is getting higher than the maximum limit.  Then, people need to slow down or stop to lower the heart rate.  If the duration over the limit is getting higher or the heart rate stays higher, I think it is time to take a rest to lower the heart rate.   If the heart rate is not getting lower with a rest, I think it is a sign to consider to stop hiking.  Especially, people feel some headache, nausea and etc, it is safe to stop hiking at that point.  Even people do not feel anything wrong, but the heart rate is staying high is probably a sign to stop hiking in many cases.


  In many article to minimize the impact of high altitude sickness, it is better to walk slowly.  However it is not very clear how slow.  This is a good method to define the pace with clear guide line.  I think this pace might be too easy especially in the beginning of hiking.   However, there is some gap between your feeling and actual situation of your body.   Therefore, it is better to see your heart rate is one of clear factor to understand your condition / situation.

   Please share your experience and data if you try this method.  It will help my further study on this topics.

   Enjoy your hiking this summer!

Garmin fenix 3 HR ~ 24 hour heart rate monitor

Trend of resting heart rate last 12 months

   The recent running watches and activity trackers from Garmin have embedded optical heart rate sensor and monitor heart rate 24/7 other than activities.  Some of high-end models has a feature to estimate stress factor, but those daily heart rate trend helps to understand the health condition.

   Anyway, the key is having / accumulating data over time as a history.   The the trend shows rough health condition.   The first plot shows the last 12 months average resting heart rate.   The late last year, the average was less than 60 bpm.  However the trend is increasing the resting heart rate.  This is probably because the time I spent for training is getting less due to injury, flu, weather (more rainy day) and expiring a membership of a fitness club.  Nowadays, my average resting heart rate is between 60 bpm and 70 bpm.

Data for last 4 weeks

   Those are clear if we see data with last 4 weeks data.   After recovering from FRU, I resume running about 2 weeks ago (June 24th), the period I took a rest, the trend is increasing the resting heart rate.   However once I resume running, the trend is decreasing the resting heart rate.   I can see a similar trend with other time.  So this is not only data, but also I do see a similar trend in a similar situation.

Last 7 days data

   Further more, based on data last 7 days, a day after a hard training, the resting heart rate is usually getting higher.  Also, if my sleeping time is less than usual, then it is also getting higher.  This is also not only this period, but I do see a similar trend in other time.   It seems that it is getting higher when I feel tired, feeling bad and etc for me.   I think the data shows if I have less sleeping, then the resting hart rate is getting higher.

A daily data

   Here is an example of a daily data.   It seems that the heart late getting lower slowly during sleeping.   If I do not have enough sleeping time, the heart late might not get lowest point since getting up and start moving for a daily life.   Also, if I sleep longer like weekend, then the resting hart rate is saturated and almost constant value after a point.  This is probably explain why many people says people need to have enough sleeping to recover.   In my case around 7 ~ 8 hours sleeping to get the lowest resting heart rate.  If I sleep more, the resting heart rate is almost constant.  So I probably need around 7 hour sleeping to have enough rest / recovery daily.

  As I mentioned a couple times in posting about heart rate base pace management during hiking.  I am really interested in my heart rate when I sleep in higher elevation such as Mt. Whitney.   In my case, I know my trend in camping in a regular elevation where is a similar as our daily life is similar as I sleep at home.   So I want to know how it changes in higher elevation.

   This is one of area to have a latest "smart watch" with embedded heart rate sensor.  It is a good tool to understand my health situation.

Mt. Whitney Hiking 2017 (11) ~ Canceled my reservation for July 14/15

Availability as of 14:23(PDT/USA)

   Like I mentioned in my post yesterday, I have just canceled my reservation for July 14 / 15.  The cancellation time is about 14:14 (PDT/USA).   Right after that, I checked the reservation site, however, I could not see the slot is back to the site.   I checked often and I do not believe someone gets the slot.   I am not sure this slot is allocated to a lottery at the visitor center or back to the reservation site.

   I really wanted to be there with this reservation, but I could not make it happen due to some other stuff happened to our family.   I hope this slot will be used for somebody else who wants to be there this year.

   I will continue posting Mt. Whitney hiking this year!

Mt. Whitney Hiking 2017 (10) ~ Canceling a reservation

99-Switch-back last year (June/2016)

   It's July now.  It would be a good time to go hiking to Mt. Whitney this summer.   This year, I got a permit in the end of September through the lottery.   However, I wanted to be there earlier and I got a slot in the middle of July after the lottery.
   Originally, I planned to be there in July instead of September and I would cancel a reservation in September.   However, there are many things happening recently and it is hard to be there in July.  Therefore I am going to cancel a reservation in July this week.  I am not sure if the reservation is back to the reservation site right away or not.  But there might be a chance somebody who reads my blog to get the permit and I just notify it in my post.  Basically I cannot give the permit somebody else, only thing I would do is to cancel the reservation.   I just checked the availability on the reservation site, there is only spot on July 10th for two for overnight permit as of now, Noon on July 3rd (PDT/USA).

Availability as of noon on July 3rd, 2017 (PDT/USA)

The reservation I am going to cancel is an overnight permit from July 14 and 15 (Fri & Sat) 2017.  I plan to cancel around 2 ~ 3 pm (PDT) on July 4th, 2017.   I am interested how soon the permit is back to the reservation site or not.  I will check it after my cancellation.

I am not sure if other people can get it on the reservation site, but it might be worth to check if people who are still looking for a permit this summer.  Maybe there might be some chance.

An example of usatg for Garmin fenix 3 HR ~ Estimation of Lactate Threshold

Lactate Threshold on Garmin Connect

   The previous posting was beginning of June, so that it's been for a while.   After the injury was getting better, I just resumed running, however, I got really bad flu and I stopped running for 3 weeks due to the flu.
   I am not fully recoverd, but I resumed running last Saturday.  I ran for 90 minutes, but the pace was really slow and I only ran 11 km.   Then, I was pointing about function of Garmin fenix 3 HR, I keep my eyes on the VO2max and Lactate threshold estimated by the device.  For VO2max, as I reported, the number was dropped to 36 [ml/kg/min] and a little recovered to 39[ml/kg/min] after I resumed running late last month.  After 3 weeks of resting, it was dropped to 38[ml/kg/min].  Probably, the ratio of dropping was slowing down and even if I rested for 3 weeks, the actual dropping is very minimum.
   However, the lactate threshold is a bit different.  The Garmin device provides 2 numbers, one is heart rate and the other is pace.  I am not really sure what the relationship for those 2 numbers.  Based on my recent data, the heart rate value is almost the same which is around 164[bpm], however the pace is slowly dropping.   It was 5:40/km in March, but now it is dropped to 6:28/km.  It is about 1 minute dropping.  Actually, I felt my breath is getting higher than before even with slower pace.  The number is probably indicates that situation.   To see my training progress, it is probably good to monitor those 2 numbers, VO2max and Lactate threshold especially the pace.  I will post how those numbers get improved.

   Before the injury, I had done a level 2 of full marathon menu.  But I guess it is better to back to level 1 after a few weeks of slow jog.   I am thinking to run every other days since I just resumed running after flu.