Agreed. Can someone spell this out to me like I'm 5? Not looking for examples of what can be learned about individual responses, but actionable training changes that might lead to predictable results.

Looking for "if X happens, do Y, to achieve Z", "if A, do B to get to C faster", or "if D, then you know E"

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Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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📱 Check out our app → Saturday: Pro Fuel & Hydration, a performance nutrition coach in your pocket.
Join us on YouTube → Saturday Morning | Ride & Run Faster and our growing Saturday User Hub

Yikes, 3L per hour is impressive. Out of curiosity, have you ever done an IM? If so, do you recall what you did for nutrition? How’d it go?

I’m struggling to understand how us sweaty folks can physically compete for 9+ hours (longer for me) without slowing to a crawl.

Not since wide use of power, sharing of training data, nutrition info, etc has become prevalent. I was signed up for Copenhagen 2020 due to trying to play to my strengths (I.e. not ridiculously hot/humid) and I wanted a KQ, but a 2021 IM isn’t in the cards due to work.

For 70.3s I use precision hydration on the bike and base salts on the run.

One application I could definitely use this for is heat acclimation; in particular, lowering risk of heat stroke. For example, the last heat session I did raised my temp by more than 2.5 degrees C. I think you only need 1-1.5 degrees to get the benefit. If I’d had this device, I could have backed off.

Not to be a contrarian, but sometimes we can get lost in metrics and metrics can thwart our efforts. Every now and then I forget my devices and when I do, i find my overall performance seems to go up when purely based on perceived exertion. I think sometimes staring at my heart rate and watts tells me I am at my limit and cant last and that becomes a self fulfilling prophecy. I love metrics and devices but I think we should all remember to splice into our workouts efforts which are naked.

What useful data do you find the device gives you that can’t already get from other existing tech (HR, power etc)?

The CORE device monitors your body temperature.

The most applicable use would be during a heat training block. By knowing your core body temperature you can figure out pacing strategies and how to cool yourself as best as possible to keep your internal temperature down and hopefully avoiding implosion!

With the proliferation of e-racing on Zwift, etc I can see a benefit to wearing it during indoor workouts too where it's easy to overcook oneself.

I’m far from a scientist, and neither is Kevin Poulton, but look him up on several podcasts and maybe some papers online as well (although not certain what’s out there beyond podcast land). I’ve got some general ideas of how it may help an excessive sweater not dig a hole while living in excessive heat and humidity (meaning n=1, myself), and I’ve got a hypothesis but I’ll wait until next year to share IF it works. I’m mainly hoping to strike a balance with indoor and outdoor training that keeps me adequately heat acclimated for where I live, but not dig a hole from doing everything in the heat/humidity. I generally don’t race in the summer because it’s hard to do much quality outdoors, and I’ve also botched preparation for fall races because of likely chronic dehydration and over exertion in the heat leading to being worn down and injured.

Basically, I’m hopeful. I also think there will be more coming out on what people have done once the olympics are over that may provide useful. If not, it’s $290 USD so no big deal.

i'll make sure to check out that podcast you recommended.

some insightful posts already from the Norwegian Tri Team on their use of CORE in preparation for Japan's heat, including how they selected their race kits. HERE is a link to that blog post.

ROFL!!!!

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"see the world as it is not as you want it to be"

I was part of the group that used the Core device to monitor body temp. For this I found it nice as I typically have an epic meltdown yearly due to the Tucson heat.
Right now, to give you an idea of the Tucson climate it's very similar to east coast with temps in that 96-104 range, humidity in the 60-70% range and a high dew point. The dew point is usually ~ 2F cooler than my DC athlete's dew point during monsoon season whenever I check.

First the downside. I found that the app often had large gaps in the data on ~ 80% of the rides I did. This happened indoors or outside. You can move the screen to your garmin. I struggle to see what's on there as it is and one more data field would have shrunk everything more. It's easier to pull my phone out between intervals, leave the app open when riding indoors or go home and look at the app post ride. You can go online and see what happened as the device is always recording but it was a bit frustrating to be doing intervals, watch your temp climb on the first group of intervals, check the screen on your recovery in the second group and realize that the app hasn't shown core temp for the previous 20 minutes. That is my only frustration with the device.

A few of you asked for answers/actionable items. And this is where the device shines.

If you're someone who typically struggles in heat you can mostly monitor your core temp in real time.

ok so great, but what does that mean for me?

As you do intervals, the environmental conditions get more extreme, your ride goes on in duration etc you'll learn where your danger point is. Where is the inflection where body temp increases above a certain point and you crater? If you know that's say 101.7 and you see your core temp getting close to that, you can make decisions.

Above that inflection you blow up, below that you're doing fine to ok to degrading performance as you get closer to that temp . Now if you're in a workout and you see your core temp get close to that point then you know to back off, increase cooling mitigate the increase in some fashion. The take away is that you have a real time device telling you when you get near or in the danger zone. Most applicable to short intense sessions, long rides/runs, interval sessions & of course racing bc who wants to blow up there?

Going 10w slower on the bike may cost you 5 min in the bike leg but how many minutes is shuffling the last 10k of the run costing you? With the Core device you can monitor that as you race/ride/run then make the decision to push, drive your core temp past that point and hope you hit the finish line before melting or back off and hit the finish line probably in a much faster overall time compared to blowing up.

The second actionable item is you can implement a heat training protocol in your training and monitor if that point where you meltdown is increasing. Maybe it goes from 101.7 to 101.9 before you crack like an egg. When it comes to key workouts or racing now your margin of error has increased. If you don't have one of these you have to cross your fingers & hope that your heat tolerance protocol is effective.

The third place it's useful is how fast does your core temp ramp up as you increase intensity and which intensities/ % of FTP drives it up the most and how fast. We all know that doing vo2 work is going to increase heat produced/internal temp faster than tempo work.

How fast does a long tempo block drive up your core temp? What about a vo2 block? You get real time data on this stuff. Great you're thinking, how can I implement this?

Let's say that you realize riding ~85% causes a long but gradual increase in temp but you never get to that break point or rarely and that 106%+ of FTP causes you to spike your core temp rapidly. Now you can look at the weather and then tailor your intervals based on that. If it's an above normal temp day/higher than normal UV index day maybe you don't go do vo2 intervals and you do tempo intervals instead. This could allow you to get the same kJ of work done. Where as if you tried vo2 intervals you may have blown up after the first third of your set bc your core temp went to high.

If you guys have questions I'm traveling the rest of the day, will circle back tomorrow afternoon to answer them.

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

Brian,
Thanks for that detailed response. I think this has a lot of promise. I hope to hear of some protocols folks are using and maybe see some literature come out on it.

In the meantime, I suspect I have a couple data-nerd clients that may be interested in the next year or so. For the bulk of my clients, just managing power meter, HRM, head unit, syncing and uploading training is probably enough for now. lol

Does this display as a new field on TrainingPeaks? If so, how. Could be interesting for me to use as a coach if it becomes a pretty streamlined process of interpretation like power/cadence/speed/HR etc have.

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Dr. Alex Harrison | Founder & CEO | Sport Physiology & Performance PhD
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📱 Check out our app → Saturday: Pro Fuel & Hydration, a performance nutrition coach in your pocket.
Join us on YouTube → Saturday Morning | Ride & Run Faster and our growing Saturday User Hub

So helpful. Thanks for this post, Brian.

[quote desert dude
First the downside. I found that the app often had large gaps in the data on ~ 80% of the rides I did. This happened indoors or outside. You can move the screen to your garmin. I struggle to see what's on there as it is and one more data field would have shrunk everything more. It's easier to pull my phone out between intervals, leave the app open when riding indoors or go home and look at the app post ride. You can go online and see what happened as the device is always recording but it was a bit frustrating to be doing intervals, watch your temp climb on the first group of intervals, check the screen on your recovery in the second group and realize that the app hasn't shown core temp for the previous 20 minutes. That is my only frustration with the device.[/quote]
Great post. A couple of questions.

1. Surrounding the part I quoted - when I ordered I received an response indicating to put the monitor on 20 minutes before workout to negate this type of thing. Did you try that? And If so, did it matter? To that end, have any of their updates they’ve pushed out improved performance?

2. Surrounding the 101.3 to ~101.7 or .9 I’ve seen in multiple places. I’m failing to recall where that comes from? I assume if you do whatever ramp protocol you’re going to find that spot on your own?

Thanks all for the commentary here!

I was one of them too! Just a bit of background, I’m not a data nerd, I’m not obsessed with the numbers, and not a technical expert, so offer the “simple” feedback.

Where I found this helpful was in understanding the impact of a workout. There were some workouts that I struggled with, or found I took longer to recover from - these are where my core temperature went higher than at other times. Texas summers are hard to control, but I’m doing these sessions again I’ve been able to identify more effective cooling strategies or recovery strategies which will allow my training to be more effective and also help in racing in heat. Having this data helped me learn more about my “feel” and make more specific or informed choices during training or recovery.

Core temp awareness I see as another piece of the jigsaw puzzle, as all things data is only as good as your understanding of what to use it for. Living in South Texas I have found I’m coping better training in the summer heat so that’s a huge bonus.

It was super easy to set up, and use.

I have been one of the testers as well! I am currently living in the hot & humid Woodlands, Texas where I have moved to almost 3 years ago from Boston, Massachusetts. I wish I had CORE back then, because I will never forget just how horrible I felt the first few weeks of trying to train during the Texas summer. It would be interesting to see the difference between back then and now.

As others mentioned, CORE is very easy to use and although I was a bit hesitant going back to wearing a HR strap, it has been a non issue at all. I do wish the battery itself lasted longer as there has definitely a few times I would forget to recharge it, and not realize until it was too late.

During this testing period, I have been using the CORE to collect data during sessions rather than guide my sessions . As an avid user of both power /HR on the bike and STRYD power/HR on the run, it’s been great to see how my body temperature correlates with both, and I’ll definitely be using CORE data to guide my pacing strategy come the IM world championships.

While I found my body temperature to be quite similar on most training days, I was quite surprised what happened when I wore my CORE during Lubbock 70.3 last month. Lubbock is known to be a very hot race, that always ends up with a wetsuit legal swim, and this year was no different most likely due to the crazy storm that rolled in the night before race morning. The air temp was actually only 66 degrees at the start (87%) humidity, which is quite cooler than what I am used to training in at home or what Lubbock usually dishes out. I wore my CORE during the swim, and although you can’t measure your core temp while swimming, the second I took my wetsuit off, my core temp readings were available. And here is the surprise. Though I didn’t feel hot, my core temp at the start of the bike was already higher than it was during any training session including 3-4 hour outdoor bike rides or double digit runs in much higher temperatures.

Don’t get me wrong, I love wetsuit swims, but perhaps this is something that Ironman may want to look at when deciding just where to measure pre-race water temps. I didn’t necessarily feel hot while riding so I didn’t utilize aid stations to cool my body (remember – I was only collecting info not being guided by it), but this would explain why I struggled to put out my usual 70.3 power during the race. Even though my core temp lowered a bit throughout the ride thanks to my lower than usual power output, I still ended up with the highest core temp ever over just a 2 hours and 16 min of riding. The trend continued on the run, and even though I was trying to cool my body down at each aid station, I found it quite difficult to actually lower it. You bet, I will be paying close attention to my core temperatures out of the swim in the future.

I look forward to using CORE in my prep for Ironman World Champs in October, and would also love to see the data incorporated into TrainingPeaks in the future.

you beat me to this question.

can this data be dumped anywhere and easily tracked? is it just in the app (that one of the st testers said was a bit buggy)?

the data is great and all, and i fully believe it can be very useful, but being able to go track it easily makes it a much better tool.


also... can we get a discount code? :-D

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80/20 Endurance Ambassador

I was also one of the testers for the Core Body temp and have used to track core temp in my training as well as using it to track that of a few of my athletes for the 6 weeks or so.


The device is very easy to use with a regular HR chest strap (you don’t notice it) but can be use with an arm band. The app is easy to use and you pair it with Garmin and Wahoo. For Garmin there is a Connect IQ app for the Core which lets you track core body temp and save all the data in the .fit file so you can do simple analysis in something TrainingPeaks as a scatter graph or in more detail in something like WKO5. For instance, you can track your core and skin temperature through a ride/run and dissect the data further comparing to power or other as you wish.


For Wahoo though, they don’t have a native setup (yet) so as a work around you can use the muscle oxygenation option and connect the core that way. It will show core temp in C or F so makes it easy to track while riding. A drawback if your ride with a wahoo (like me) is that the data saved in the .fit file relates to muscle oxygenation so you have less ability to dissect the data (i.e. you can compare core and skin temperature), but they mentioned they’ll have a setup soon. And they created a WKO5 sets of graphs to use whether you collect the data with Garmin or Wahoo.


The protocol to determine your “heat training or adaptation” zone is rather simple as explained above. However, I think it may take a couple of tries to get the best possible reading as the first try my heat training zone was lower of the normal body core temperature I normally experience in a regular warm/humid Texas summer day. Once I tweaked the zones slightly It became easier to correlate to various situations.


For instance, the 2nd weekend in June when we had “proper” hot/humid summer weather (low 90s and 65% + humidity), I hit my heat training zone within 20-25 min of riding and climbing above it thereafter by quite a bit. Of course I was hot and my body wasn’t adapted to that heat yet since HR was high ~5-10 bpm at the usual power. And thus, it was a bit tougher than normal ride which may have been easy to prevent where I held back a bit. It also led me to tweak slightly my usual fueling strategy for the usual training weather (mid 80s and humid) for such conditions. ~3 weeks later, almost same conditions (actually a bit hotter), power was normal, HR was closer to normal, and core temp actually stayed within ‘heat training’ zone and the fueling tweaks also made a big difference.


When training in Saint George last week for a week in 95+ F weather (hitting 100F>) and riding climbs like snow canyon, the heat by perceived exertion felt much more intense than normal and yet, my core temperature never hit any higher number than my heat adaptation zone riding at the same power I normally do in TX for such a ride. HR was higher than usual the first few days which I think was more related to the altitude vs the heat. Thus, while St G is was hotter than TX, it was less humid which plays a bigger role in managing body core temp.


As mentioned above, using the core and your heat zone as a guide, I managed to tweak my zones a bit better and have “pushed” the limits a bit to find my “too hot” zone! What I mean is that you can do some training in hot/humid conditions and learn at what temp 10 extra watts may be too much and how far you may be able to push before it significantly impacts your performance. For someone racing the upcoming St G or say Kona, this could be great information to use on race day or simply track your temp live to avoid getting near that danger zone and prevent walking the marathon for instance. (you could do the same for running)


Also, an example of applying it to athletes I coach: reviewing the racing data for Jana (who posted above) post Lubbock 70.3, she didn’t ride/run at her usual potential and the first thing that jumped at me was how high her body core temp (102.2F)was post the swim which was barely swimsuit legal. And though while Lubbock tend to be a rather hot race, that day was unseasonably cooler yet her core temp on the bike stayed above of what she normally would riding at the power. By the run, within a mile the core temperature climb back up even higher that it normally would for that power/pace/HR and weather conditions (102.6F). So we theorized since the swim was barely wetsuit legal and she swimming with one, probably overheated her even though she didn’t feel hot and this perhaps affected the rest of her day. (something to consider next time)


Finally, I do a bunch of testing at my performance lab and I plan to continue doing more testing with the core and I'm thinking of ways to better apply it to my athletes training (like testing body core temp while wearing certain tri suits or cooling devices like the new headbands), use it to tweak fueling strategies in various conditions, fine "too hot danger" zone, etc. But the Core team have been great at answering questions and seem rather open to feedback.


I think it’s a valuable tool for any athlete and could prove useful not only for those training in warm weather or planning to race in hot races. But also, as I used to live in Massachusetts before moving to TX, I see it could be useful for those training up north in the winter/colder months who may have early season races. Thus incorporating some form of “heat” zone training early on may help them perform better. And while those April/May races may not be in very hot conditions, it may certainly be warmer than weather those athletes may have experienced in their training hence allowing them to perform better.


Also, using it could help you streamline your heat adaptation protocols if you live in cooler weather and don’t have access to certain things (i.e. sauna). Using the core you could simulate heat adapting indoors or supplement a session with a hot bath and track your core temp to see if it is in your heat training zone. Finally, you could use it to test gear or help you modify your fueling strategies. i.e. you may drink a bit less in ‘x’ weather and a bit more in ‘y’ weather. And you could test the same with carbs/electrolytes.

If you have any questions, let me know.

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Jorge Martinez
Head Coach - Sports Science
E3 Training Solutions, LLC
@CoachJorgeM

Yup, you can do basic analysis on TP (using a scatter graph) or on WKO5; examples:

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Jorge Martinez
Head Coach - Sports Science
E3 Training Solutions, LLC
@CoachJorgeM

i went to order one, but my debit card blocked the transaction since it was in a different country. gonna call the bank and get that sorted tomorrow.

i feel this will be really beneficial to me. i train half my life in a remote work location. treadmill and bike are both in living quarters where the hvac is kept EXTREMELY cold. i actually started putting a space heater in front of the bike or treadmill to blow directly on me to get heated up. ive known training in such a cold environment wasnt helping me at all. i will love seeing my body temp at work versus the texas heat and humidity and inside at home on the trainer.

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80/20 Endurance Ambassador

Brian (& anyone else who have used this product).

Do you think this device could be helpful in comparing products that have a "perceived" increase in heat / core body temperature?

Off the top of my head I'm thinking back to back outdoor tests where power is maintained between two helmets or suits (with adequate time between runs to allow core body temperature to normalize)... for example, benchmarking an aerohead vs a rudy wing or a black tri suit vs a almost see thorugh white one built to be "lighter and cooler"

What are your thoughts on this??

Cheers
Mike

Yeah, that’s how the Norwegian Triathlon team tested their Tokyo white uniforms. As I mentioned above, that’s how we are planning to test some gear pre Kona. (Ie headband cooling device, kit, etc).

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Jorge Martinez
Head Coach - Sports Science
E3 Training Solutions, LLC
@CoachJorgeM

Answer to 1 - I put the monitor on when I put my hrm strap on which was when I was kitting up to go ride. By the time I let the dog in/out, grabbed my bottles, topped off my bottle from the freezer with water, stuff nutrition into my pockets, rolled bike to carpot, got shoes etc it was usually ~ 20 min. Maybe a bit more sometimes, maybe a bit less others.

Answer to 2. The temps I put in where just place holders for the convo. You need to determine you own inflection point. Your "hey this is where I start to melt down" temp could be a lot lower or higher than "my this is where I start to melt down" temp.

I spend a lot of time riding in at/near/over 100F temps with an 11/11 UV index. Then when monsoon season hits, it's just like being back in Raleigh NC but a bit with typically higher day temps (+2-6F) and slightly lower dep point temps _~2F). It could be 95F and 70% humidity at 10am when I'm rolling back in from my 4+ hour Sunday Funday ride.

(Having spent summers in both Raleigh & Tucson, you guys in the RDU area have it pretty good during the summer comparatively. Summers in Tucson are much harder to train in due to how fast it gets hot, you just don't get that 10-12F rapid temp increase in an hour there that we get here once the sun comes up)

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

Have you experienced any drop out issues with the device? How often does the device need charged? On your garmin, can the ciq data field be added to an existing screen with other native data fields? How noisy or how much variation in the data do you see on your garmin?

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blog

Steve - not to derail, but how much outdoor work do you do/what is your schedule through the summer? I piss and moan about living in Hilton Head, but your situation is much worse but you seem to do pretty well with however you’re breaking things down.