I experienced a similar thing this morning. I made a conscious effort not to focus on my heart rate, instead I really tried to dial my breathing in. It worked to a certain degree but I knew that I was having to work harder. I also drank more fluid during the hour session.
Personally, unless you’re trying to actively recover or hit a specific TSS, I wouldn’t dial it down.
It usually takes me about 2 weeks to acclimate to the (dry) heat of central CA, which from what I’ve read that amount of time is average. Have you acclimated yet?
Did a quick search and found this blog post:
Heat is an additional stress. Zone 2 will feel harder because now your body has to also prioritize cooling itself. So you’re doing additional work (but not the raise your FTP work), coupled with RPE dramatically increasing. However, just because it feels harder doesn’t mean you’re necessarily pushing the intended physiological fitness goals (ie: z2 is still z2, it just feels like threshold efforts.) This is why it’s preferred to “optimize” training with a cool room and fans so your body doesn’t have to deal with the additional stress of offloading heat. However, the affects of the additional heat stress can be mitigated through heat adaptation (HA), similar in concept to how one would adapt to altitude. If you have to live, train and ride/race in the heat, it’s probably best to just become better heat adapted. If you “dial your effort back” then you are no longer doing the intended workout.
That is a bit dated, but some good podcasts on HA to listen to are:
Listen to How to Get Faster with Heat Training - Ask a Cycling Coach: 103 from Ask a Cycling Coach - TrainerRoad Podcast in Podcasts. Ask a Cycling Coach Podcast - Presented by TrainerRoad: Ask a Cycling Coach: 103 – How to Get Faster with Heat Training on Apple Podcasts
Listen to How to Train for the Heat: Part 1 with Dr. Stephen Cheung from The Sonya Looney Show in Podcasts.
The Sonya Looney Show: How to Train for the Heat: Part 1 with Dr. Stephen Cheung on Apple Podcasts
Listen to How to Heat Train for Endurance Events with Balance Point Coaching from The Sonya Looney Show in Podcasts.
The Sonya Looney Show: How to Heat Train for Endurance Events with Balance Point Coaching on Apple Podcasts
Additional discussion can be found here:
however the blog entry in the first post points me back to the same study:
I quickly skimmed that early. It roughly states the protocol was to ride at 35C / 104F for 100 minutes (2x45-min with 10 rest between) at 50% VO2max. It seems like the protocol was 10 days (total? or 10 days heat?) of alternating days.
Just did Dans yesterday at 92F and 45% FTP is roughly 53% VO2max according to WKO4 modeling.
My translation: Lazy Mountain-1 for 90 minutes, every other day for a couple of weeks.
@PusherMan & @bbarrera, that’s about what I was thinking. My heart is doing more work to pump blood to extremities, but my muscles aren’t doing any extra work. I try to keep my workouts to mornings & evenings when its cooler, I do some zone 2 runs on my lunch breaks. I’ve been doing this since December so, yes I’m heat adapted. The heat really doesnt bother me in terms of RPE on my runs.
@MI-XC thanks I listened to some of it, and now understand why my Sept 2018 ramp test was so good, and why my vo2max fell off a cliff in Nov 2018.
UPDATE:
Had another XCO race this past Saturday (
) after 10 days of HWI Heat Training. Temperature was cooler than expected (measure on Wahoo Bolt) with a Max temp of 87.8 (start line in the exposed sun) and an average temp of 71.6 (in the forest tree covered with 99% shade). Humidity was pretty high though. The temperature and humidity was a non-issue for me during the race this time, though I didn’t particularly see anyone else overly suffering 
. On the other hand, I won the race with 1.5 minute uphill sprint to the finish line where I hit a lifetime power PR for that time duration!
Two weeks ago at my previous race under similar conditions I melted and suffered greatly. I also felt horrible after that race and suffered from “heat fatigue” into the next day. I felt none of those effects this time. In fact I felt so good that the next day (Sunday) after the race I went on a hard MTB ride on a local trail for 2 and half hours with 3,000 ft of climbing. The average temperature during this ride was 77 degrees (max 100.4). This was a pre-ride of the trail for my next XCO race. Doing this would have been unthinkable 2 weeks ago and is a vast difference than my 62 degree cool training environment of my basement.
I have another XCO race in 2 weeks which is expected to be roughy the same weather (70-80s and humidity of course). This week is my scheduled recovery week. I will do this entire week with no fans and also throw in a few HWI sessions to keep my adaptations. I’m not sure if I’ll do all of the 5 sessions this week ending in 30 mins of HWI like I did the previous 2 weeks. It’s my understanding that it’s not needed to maintain HA. Priority will be to ensure I actually recover this week as I will be starting GBMV (second half) next week.
Conclusion:
My HWI training definitely helped. I’m not sure if it was mental, physical or both. Additionally I can’t determine if these results were the Anticipatory Effect (placebo effect) or actually due to the HA training, though science seems to suggest the latter. Either way, my N=1 experience is that it helped not only during the race (didn’t stifle my ability) but also my recovery, so I will do it for all of my warm weather A races.
congrats on the results!
I’ve got a bit of hard data for heat acclimatization from last summer. All my training is in the garage, mostly in the afternoon when its hot and garage temps are 90-100F (30-38C). Last August/September during SSB-1 block I found myself doing at least one or two long/low-intensity outside rides on Fri/Sun weekend because I was selling a car. The temp on those rides were typically 95-104F.
After that block was completed I had my best ramp test (vo2max increase), and subsequent training had a clear reduction in heart rate. Anecdotally I was able to do 90-120 minute sweet spot rides without fueling, reflecting a reduction in glycogen usage. At the time I didn’t make the connection to the info in the How to Get Faster with Heat Training podcast episode 103. @MI-XC thanks again for pointing me to that episode!
Three days of racing in Boulder - temps were about 85 at the start and got to around 95 on the second day. Had an ice sock both days, for the crit I had one for my warmup as well. I felt amazing. And I usually do horrible in the heat. I don’t think my heat training for Tulsa had anything to do with it. But, just kept cool.
I have a 50 miler on July 4th in Breckenridge. It won’t be warmer than 70, it usually feels much warmer. Probably roll with an ice sock and get one at the start of the second lap.
Update:
I’ve done my race this week-end - I think this heat acclimation stuff really works well. It was extremely hot (IM Nice) and I wasn’t overheating. Granted, I was not running at full potential at all (long story) but I really felt comfortable at the bike - while a lot of people were overheating in the middle of the bike leg already.
For the record, I did:
Only thing I thing I should have done is at least one long ride or run (I did one run of 24km, but it was an especially cold day - 15C, so I’m not sure I can call it heat acclimation - at least not for IM Nice 
).
I will certainly do the same protocol for next races in the heat !
I’m prepping for the Maah Daah Hey 100 mountain bike race in the badlands at the beginning of August, and I did my first two sessions of HWI following your protocol yesterday and today. Made it 18 minutes in the water yesterday and 25 today. Two issues I’m running into:
Half an hour in a hot bath after a hot ride kinda sucks. Ah well.
Try wearing a winter hat and keep as much of your core under the water, possibly under water up to your neck. I have a big soaker tub, but in your case having the bottom of your feet out of the water isn’t that big of a deal. Maybe put on wool socks if they will be out of the water the whole time.
I’d stay in the tub for the full 30 mins EVERY time. Even if you have to raise up out of the water to your waist temporarily to cool off, still stay in the water for 30 mins and return up to your neck when you can. Your temperature will take time to get to 101.3 (10+ mins) and may only reach it towards the end of the HWI. Try having the tub a little warmer (107-109 F). Just stay consistent and whether or not you do the protocol perfectly, you are still getting some physiological benefit and all of the mental benefit.
It gets less miserable as you continue your HA. I’m doing a FTP ramp test today followed by HWI.
Thanks for the tips. I’ll definitely GET to 30 minutes, probably next time. I just couldn’t do it these first couple. I’ll try the hat next time. Even at 25 minutes my temp was still at like 99.7º. The tub this morning started at about 111º and got down to like 107º IIRC. I’m getting better at making things happen efficiently as I go.
The mental benefit is a big part of what I’m looking for. Typical temps for the race are 95-105º, and the first year I tried it, it got up to 115º.
Two questions:
Thanks!
if you haven’t and are able (weather conditions, schedule) then I’d recommend training in the afternoon when it is hot outside.
My outdoor rides are usually afternoon/evening in the heat, but with a couple of kids, it can be tough to get that time. I lead a group mountain bike ride on Thursdays, which is fun, but not exactly training. My office/pain cave is usually between 75 and 80ºF when I’m training (well, at the beginning. At the end, it’s more like 77-82º 
)
mines in the garage, 90-100F this time of year in the afternoon. Perfect for heat acclimatization 
I’ve taken my temp after workouts as I let the tub fill and I’ve always been within normal range (97.7-99.5 F), generally 98.X. I know I’m hotter than before the workout, as I’m sweating profusely and in a heavy hoodie and sweatpants, but my temperature doesn’t seem to reflect that.
As far as my sweaty after workout sweatpants and hoodie, that usually lasts through 3 days of HWI. After I get out of the tub I let them air dry on the edge over night and put them away the next morning. I replace when they stink. So I had one set of sweats for the Tues, Wed, Thurs workouts and HWI, then another set for the weekend.
Good to know. That’s pretty much where I’m at, and wasn’t sure if I was just “running cooler” or something else was going on.
Thanks!
Anyone track their weight while doing HA? I’ve found mine is up a bit from what I’d come to expect lately, which kinda makes sense if plasma volume is growing? Or maybe it’s just the ice cream and such
Huh, I never even thought of that. Yes, I am up a few pounds as well but thought it was because I haven’t been as strict with my diet. I’ve never seen anything regarding weight gain and HA, but I’d love for that to be the cause and not me!
EDIT:
As the climate changes and it becomes hotter, the body adapts via a process known as heat acclimatization in order to reduce the negative effects of heat stress. By the second day of heat acclimatization, sweating starts sooner and takes place at higher rates, which improves evaporative cooling and reduces body heat storage and skin temperature. Thus, after heat acclimatization, fluid requirements will be higher due to increased sweating. Heat acclimatization also improves fluid balance by better matching thirst to water needs, increasing the blood volume and increasing total body water.
In the summer, body weight can go up by several pounds due to increased body water. This is accomplished through fluid-conserving hormones such as aldosterone, which allows the kidney to retain more fluid and reduces the amount of salt in sweat, a measure that also aids in water retention. The increase and stabilization of total body water can only be accomplished by continuing to exercise in hot weather and will not occur in people who spend most of their time indoors in air-conditioned environments.