Heat Conditioning Week 1

For the last week I’ve been doing a heat conditioning on Farley, and arguably on myself since I’m the one wandering about the arena at the same time. Since unfortunately I have not perfected the art of sitting in the bleachers under an umbrella and yelling “trot!” and having Farley proceed at a nice working trot around the arena. 

The point is......I’m ready to share with you my first week’s worth of data and some of my commentary! 

First some definitions and notes:

1. Because the start of my experiment also coincided with the start of a heat wave, I decided that in temps over 100 degrees, Farley could run around bare. I might change that in the future, but I was worried about putting a sheet or saddle on her and forcing her to run around in such extreme heat conditions, especially because we had never done it before. In the end, only one day was cool enough (under 100 degrees during our session) that I “covered her up” for our session. Instead of a sheet, I chose the heaviest, biggest saddle I own and added a rump rug. I think that duplicates the conditions that I’m conditioning for better than a cotton sheet. 

2. The Heat Index shown on the table was calculated from the National Weather Service using temperature and relative humidity.  Yes, our weather in the past week was that miserable.  We set a record for the number of days over 105*F in a row....Weather data was recorded at the time of the workout.

3. The “Start” parameters were taken in her paddock, in a flysheet, before leading her out.  The “end” parameters are taken in the arena immediately after stopping the work out.  I took Pulse first, then temperature since her heart rate drops faster than the rectal temperature. “Post” recordings was after walking over to the shade and hose and putting water on her and scraping.  Takes me about 5 min after finishing workout to take the end parameters and then walk her over to the cooing area.  Another 5 min of cooling, for a total of ~10 min post workout the “post” readings were taken. Cooling = in shade with cold hose water applied. 

Here’s the raw data: (some columns hidden for clarity) - click to make it larger

My observations and thoughts:

How many times? I was able to do 4 sessions with Farley during the first week. Day 1 on Week 2 is exactly one week after I started this process.


Starting Temperatures: Only on the first day the starting temperature elevated over 100*F.  As time progressed, her starting temperature DROPPED each day, even though the heat index (and weather temperature, not shown) was INCREASING each day.

Body temperatures over 101*: I only saw body temperatures over 101*F twice - once on the first day after cooling, and on the last day, at the end of the workout.  However, on that last day, the body temperature dropped back below 101 at the end of the cooling period.

Body Temperatures observations: Only on the first day (which was also the first day of the heat wave) did her body temperature continue to significantly rise from the end of the session, even after cooling.  In general, body temperature remains elevated after a session, even after pulse rapidly drops.

How long for Body Temp to reach starting temps? It would be interesting to see how long it took for her temperature to return to prior session levels, but I haven’t had that much time on my hands!!!!!

Respiration? I could not reliably take respiration counts so they are not included.  Only on day one did respiration stay elevated at the post cooling stage (not inverted, but still visibly elevated). 

Starting Condition: For all the sessions during week 1 Farley was absolutely drenched in sweat just standing in her pasture (do you blame her?  I’m sweating just thinking about how hot it was....).  At the end of the work out, she had visible wet gooey sweat on most of her body.  On July 6th (first workout of the second week), which is the only day so far that has NOT been in the triple digits, she was dry in her paddock with some residual dried salt on her neck.  Her body temp was also the lowest it had been so far. On this day after 15 minutes of a working trot saddled with a full rump rug, I stopped the work out intending to end it at that point (since I wasn’t sure how working her in a saddle and rug would affect her, even in the cooler temperatures).....but she was still absolutely dry, with only some dark damp areas under her girth.  So, I sent her out for another 5 minutes at a more extended/active trot (and she cantered some) to try and get some more heat.

Sweat Composition: The sweat on her body on week 2 day 1 session was different - more like water, less gooey and drippy.  I’m not sure if this means that the actual composition of the sweat is different or something different. 

Tired? At no point was Farley “tired” after any of the sessions. She was spooking at the scary side of the arena, offering extended trots and canters, although what we were working at, and what I asked for was a “working” trot pace.

Did I get any benefit of heat conditioning yet? I think that the results in the first 3 days of week 1 clearly show active heat conditioning.  All three sessions were 10 minutes and had increasing temperatures/heat indexes.  However all 3 days show a progressively lower body temperatures and pulses before, during, and after work. It was based on these numbers that I increased the duration of the next session to 15 minutes.

Rectal Temp thoughts: I’m not sure what exact numbers I should be targeting for rectal temperatures.  I’m more familiar with pulses and I’m very comfortable with the fact that the heart rates are not excessively high during the workout, and are coming down very quickly.  I don’t have the experience with rectal temps.  Preliminary research of studies that looked at horses and heat seem to work with 40*C (104*F) and 101*F.  ie, they will exercise horses until a rectal temperature of 104*F is reached, and then cool to 101*F or below.  I dont’ think I need to reach body temperatures as high as 104 to see benefits of heat conditioning and I would rather error on the side of NOT excessively stressing my horse two weeks before Tevis, so I think working in the 101-102*F range is probably appropriate, as long as I see temperatures come down to 101 or below after cooling.  

Heart rate thoughts: I think one thing that I’m missing is the actual rate of heart rate drop after the session. How many minutes did it take for her HR to drop below 60?  Below 50?  I think for now the 1 min and 10 min mark that I’m getting readings is sufficient.  The extra time and effort in getting more readings wouldn’t gain me enough additional information and if this protocol gets complicated and time intensive enough, I’m not as likely to get out and get ‘er done.  Know thyself......

I also think that I might need to ask for more effort or a longer time.  I don’t think her pulse is elevated enough during the sessions.  Making sure I keep her moving consistently at a working trot is important.  She’s not even near distress or even tired and I have enough body temperature data to back up my decisions so I’m more comfortable asking her to keep on motoring on.  I was super conservative this week since I was trying something new, and I intend to continue to be conservative, but I’m starting to have some confidence in the protocol and the results.

Using water to cool the horse thoughts: Besides using objective data to measure a horse’s response to heat and work, the other really interesting piece of this is seeing what really makes a difference in cooling a horse.  Shade is SO IMPORTANT.  Water and sponging and scraping is nice....but especially if I didn’t have shade for my horse, I think I would probably error on the side of putting less water on the horse overall and just focus on small key areas like over the jugular, flank, chest and girth.  I’m noticing the excess water left in the coat on places like the back and rump, even though I tried to scrape it off as best I can, seems to really impede the horse’s ability to continue to cool down once you’ve stopped actively putting water on the horse.  More water ALWAYS remains in the coat than you would like. The chest, neck, girth, flank areas are already wet because of the sweat, and they are in “shady” places on the horse, so I think water left in these areas post sponging/hosing in these areas isn’t quite as critical.  I’ve been hosing Farley completely off after the sessions because that’s what I usually do after a ride at home that I have a hose handy....but I rarely if EVER do this at a ride.  I had never analyzed or really thought about it before, but I think I was on the right track.  There’s probably a reason that horses sweat on their “shady” parts before their big expansive “sunny” parts - and I think I’ll use as my rule of thumb to not sponge Farley at a ride in areas that aren’t already damp/wet with sweat. 

Plan for Next week: I got 4 sessions in last week and I’m planning on 4-5 sessions for week 2.  I think this is about right.  I think doing something TOO consistently gets me in trouble - letting days off happen because of sheer laziness or because life gets in the way is a good thing.  I tend to error on the side of too much when I design a protocol or program much rather than not enough, and taking days off as they come lets my horse recover if what I’m doing is on the side of “too much”.  It also reminds me of what my horse looks like after some time off which is a very good thing!  A tired horse can “sneak up” on you!  Another rider who is doing a similar program is averaging ~3-4 days heat conditioning and then 1 day off, so I’m in the same ball park.

I’ll report back in another week.

Any comments?  Is anyone doing this and tracking the results?  Anything I’m missing from the data so far?


If someone has some time on their hands....I would love to see some data on how long heat conditioning “sticks”.  I know that to gain it takes 14-21 days of doing something in the heat.  But once you’ve done this type of work, how long can you hold onto it? 

So far in my experience heat conditioning for my body doesn’t seem to hold from summer to summer.  I spent one summer in on the coast working, and when I would make trips into the valley it was HOT and I felt like a wilting flower.  Even though they were temps I would normally have been fine with when I lived in the valley. However, if I screw up and get too hot and go into heat exhaustion (happened to me once a long time ago), then I seem to suffer the consequences of reduced heat tolerance for about 2 years.  So if I do good it doesn't last, but if I screw up it does?  Doesn’t seem very fair.........

Alright folks, time for me to head out and do week 2 day 2 session and gather some more data for next week!