I am from a cold climate and have never fared well running in the heat. I have been quite fearful of my upcoming 100 mile race in Victoria where the temperatures may crack 30 degrees during the day. Rather than feeling defeated by the heat I channeled my taper energy into trying to find the best way for me to acclimate to the heat while still residing in cool Hobart. In this post I will outline my heat adaption process to get myself ready to run in the heat.
Heat Acclimation Protocols
The human body is remarkable and it will adapt to its environment. Thankfully heat adaptions are quite quick to develop. They can be developed in as little as 7 days given the right protocol is employed. Once the adaptions are achieved they can be maintained by exposure to heat once every few days. Heat adaptions impact the following physiological parameters:
- Heart rate at heat decreases
- Core temperature decreases
- Thermal comfort in heat improves
- Blood plasma volume increases
- Sweat rate increases and sodium concentration in sweat decreases
- Sweating begins sooner as the body gets better at reacting to heat
- Skin temperature decreases
- Exercise capacity in heat improves
The onset of heat adaptions over time is shown below in Figure 7.5 from Training Essentials for Ultrarunners by Jason Koop.
There are two types of heat acclimation protocols, active and passive. Active involves exercising in the heat, this one is easy if you live in a hot climate. You just go for a run on a hot day. Passive acclimation involves sitting in a hot environment such as a sauna or a bath to expose your body to heat and get the adaptions.
Since I don’t live in a hot climate I decided to implement a passive heat adaption protocol. The hierarchy of passive heat adaption protocols has dry sauna being the best option then hot water immersion. Wet saunas are not advised, I’m not sure exactly why.
My Heat Adaption Plan
I decided to roughly follow the plan from Training Essentials for Ultrarunners that starts about 2.5 weeks before race day. I found an infrared sauna just down the road from my place at Totum movement that costs only $35 a week for unlimited usage. This is ideal for me. I can do a run from home, run past turn the sauna on to warm up then swing home and grab my gear. The plan is to expose myself to heat for at least 7 days in a row for maximum adaptions then to maintain the adaptions with additional heat exposures.
I continue to do the runs I had planned and just end each session with a sit in the sauna. Starting off with shorter duration and building up to 30 minutes total time in the heat.
Following the Plan
I began my plan on the Monday almost perfectly in alignment with the protocol. The only difference is that my race day is on a Friday. I started out with a shorter sauna session. It was difficult but not excruciating. The following day I increased my time in the heat with the goal of getting up to 30 minutes as soon as I could.
On the third day there was a thunderstorm in Hobart and I only got to run for about 15 minutes before the sauna while finding a break in the deluges. It was super hot and muggy and I was already sweating after 5 minutes of running. When I hopped into the sauna I started sweating within 2 minutes. Typically up to this point it would take over 10 minutes to start sweating. This session was my hardest so far. I persisted and got up to 28 minutes before I pulled the pin. I had initially been enjoying my saunas but after this one I was having second thought about following through with the protocol. Thankfully after getting out and drinking some fluids I felt amazing and euphoric. I guess the short term pain is worth it sometimes.
On the fourth day I had sailing in the evening. The sauna closes at 630pm so I reverted to the next best alternative which is hot water immersion in the bath. This was my hardest session by far. Already tired and probably dehydrated from a run before sailing then going out on the boat for a few hours. The bath was super hot when I climbed in. I immersed my body up to my neck and only kept my hands out. My plan was to stay in for 30 minutes but I only made it to 28 minutes of torture. I stood up and kicked out the plug and ran a cold shower. I see stars and nearly faint and have to lie down in the bath to recover. This leaves me questioning if I am cut out for the heat.
The following day I did a long run home on a 27 degree day and I felt like my body was getting better at thermoregulating. I was pouring out the sweat but I felt like it was cooling me more than usual. And the heat of the day did not really impact my performance. I felt good all run and it gave me hope that I may survive the run if it’s hot. Straight after this run I was back in the sauna and it was a great session. I feel like this was a turning point for me and from this point onwards I felt better at coping with heat.
Thankfully the sessions gradually got easier, probably due to me actually getting some heat adaptions. I started incorporating cold plunges afterwards. Scott the owner of Totum has a chest freezer with ice bricks in it. He is so enthusiastic about the cold plunges that I was influenced into trying it. I am now addicted to the feeling of a long sauna and a cold plunge. Whatever is happening in my body results in me feeling euphoric for about an hour afterwards.
Summary
It is now 3 days away from my race and the forecast is looking toasty. I am still incredibly nervous but I am finding some solace in knowing that I have prepared my body as best I can to cope with the heat. I stuck to the plan almost religiously. One final heat session is planned this afternoon then I am travelling tomorrow morning to Victoria. It’s hot up there so I’ll get a few more days to acclimate. On Friday I run 100 miles in the heat. Fingers crossed this cold weather runner survives the heat. Below is a table of the my protocol for those interested.
