MdS Heat Acclimation

A big factor when running the desert is the heat. That’s pretty obvious. How do you train for it? Easy – you spend as much time as possible running and exercising in the heat. How do you do that when you live in England and it’s Winter?… not so easy.

Well, I have three things in mind:

  • Bikram Yoga (Yoga in a hot room
  • Running on a treadmill wearing lots of layers and with the heaters on
  • Use heat acclimation chamber

I’ll share some more the first 2 when I have actually tried them. For now, I wanted to share with you my first experience in a heat acclimation chamber.

The Prep

I spent most of Wednesday eating well and hydrating myself ready for a 1 hour session in the heat acclimation chamber at Kingston University. I drank about 3 Litres of water during the day and ate pretty well, some good carbs and the old faithful banana just before running. Perfect prep, well that’s if you don’t end up sitting in a car for 45 mins trying to get across London. Nature called… luckily, like most avid runners, my car is full of bottles. So, at the next set of lights I dashed to the boot a grabbed a 500, then changed my mind and grabbed the 750ml! I hoped back into the front and proceeded to top-up” the old 750ml race freebie. I’ve had pre-race nerves before, but never pre-training nerves!

Pre-Run Blood Analysis

Pre-Run Blood Analysis: haemoglobin and heamatocrit

On arrival I was met by a great guy called Chris. He gave me a decent intro into the session and proceeded to record some pre-run stats.

  • Haemoglobin – 15 g/dL (normal range is 14-18 g/dL)
  • Haematocrit – 48 % (normal range is 40-54 %)
  • Naked body weight – 86.3 kg (despite shedding 15kg for the MdS, I’m still kinda heavy for an ultra runner)
  • Resting Core Temp – 37.1 ºC
  • Resting heart rate – 90 bpm (usually 43 – I must have been nervous)
  • Water content of bottles – 1500ml
  • A signature to say I won’t blame him if it goes wrong

The Run

Well, I wasn’t expecting it to be easy. But I also wasn’t expecting to be horrible. Part of my job involves me training as Fire Fighter in case of an incident at the facility where I work. This involves a few days training each year in very hot and very horrible conditions wearing breathing apparatus, air cylinders, heavy gear and dragging fake casualties out of buildings. I have experienced the discomfort that comes with exercising in the heat… though, when you finish a training exercise there is cold water and fresh air. As I found out when I ran a few time in Egypt earlier this year – the heat is relentless.

Anyway, with a reasonable sense of comfort when I walked into the 40 degree, 20% humidity chamber I decided to push myself and see where my break point was. I didn’t want to go too easy and not learn from the experience. So I loaded myself up with a 7kg pack and set off at a decent pace. Picking the pace was confusing to start with as it was in km not miles, so after a few mins of testing my maths at 40 degrees I settled into my half marathon pace.

Heat Acclimation Chamber

Heat Acclimation Chamber

Now, in hindsight, this was more than a challenge… I set of at my half marathon training pace but also had 7kg on my back AND 40 degrees AND <20% humidity. Of course, it was a matter of time before I was gasping for a drink and burning up. 25 minutes into the run I had to knock the speed back to a more casual jog. My core temp had risen from 37.2 to 38.1 and then to 39.1. When you approach and exceed 39.5 and things get interesting. Although it sounds small, 0.5 degrees is a big increase… but still, I backed off to learn the feeling of where the high 38s are and where 39+ begins. For the next 30 mins I tried varyious speeds of walking, jogging and incline changes to test out my reaction to the extra effort. I would say that once “cooled” back down to the high 38s I was comfortable.

Feeling a little warm!

Feeling a little warm!

Once you are hot and your ability to cool down is limited by the ambient air temp and blood temperature, it can take a while for your core temperature to drop a mere 1 ºC. Escpecially when you’re your burning calories and generating more heat! Lesson- do not over heat in the first place. Slow and steady wins the race. I’m getting de ja vu!

Post run

After the run, Chris took all of the key data again and pointed my in the direction of towel and some scales to get my post-run dry weight. I had sweated a whopping 2.2 litres of water in 1 hour. Now, if we extrapolate that out to a 6 hour run, that will be at about 13 litres That’s approximately the daily ration of water. Chris tells me, I sweat more than the average person, but not the most he’s seen. I could have guessed that by looking at my t-shirts after a spin session or circuit class – but it’s nice to see some numbers! I therefore need to be sensible with my water ration, avoid over exerting myself in the peak of the heat (pretty obvious) and not waste water splashing it on my face etc…. I’m sure it feels great, but is an inefficient way of cooling down.

So what did the key stats tell me:

  • Body weight- I lost 2.2kg in sweat
  • Blood (Haemoglobin – 16.4 g/dL and Haematocrit – 50 %) – despite sweating a lot, I kept myself hydrated. When you’re dehydrated the haematocrit % increases as there is less water in your blood. As a consequence the blood thickens, this makes pumping the blood harder, your heart works harder, burns more calories, generates more heat, you sweat more, the % increases and you heart has to work even harder. This gets rapidly worse! So, stay hydrated!
Me wearing a 2.2kg t-shit

Me wearing a 2.2 kg t-shirt

After a nice cool shower, Chris gave me a de-brief on the session and explained my stats. He’s a keen ultra-runner himself and a very knowledgeable Sports Scientist – I was all ears! As I sat recovering, he kindly topped up my recovery shake with water. Unfortunately the shake had been in my bag for the full run; I am not looking forward to warm protein shakes in the desert!

Next steps

Over the months of December, January and February I’m going to be running on the treadmill with lots of layers and hopefully a heater nearby. I need to get used to the walk/run/walk and get a better feel for my fluid intake over extended periods. I’m also planning to start a Bikram Yoga (hot yoga) session once per week and then up this to 2 or 3 sessions per week by March. Then, in the final week or two before I head to the desert, I will be heading back to the heat chamber for some final heat acclimation session. The benefits of heat exposure are short lived (perhaps 1-2 weeks) so I’ll get the most benefit from hot, yoga, heat chamber and the saunas by maximising usage in the final 2 weeks. I just hope I don’t turn up dehydrated 🙂

If it wasn’t already obvious, I would absolutely recommend spending some time in a heat chamber- it was incredibly valuable! I know it isn’t cheap, but this is up there with the best £50 I have spent on training/equipment so far! Even if you can only find the cash to do 1 session, I would!

Time to get a sweat on!

Rob

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