Inside the Heat Chamber

Its a small room, barely big enough for an oversized treadmill and 2 stationary cycles but this is the final and main part of my heat acclimatisation training for the 2014 Marathon des Sables. I'm at the University of Chichester in the physiology department and I'm about to go for a run. 

Essentially the idea behind heat acclimatisation is to prepare the body for exposure to different weather conditions. I've been told that it is most effective in the 10 days leading up to an event hence my presence in Chichester now. Over the next 9 days I will be subjecting myself to 7 heat sessions each lasting for around an hour. It is hoped that my repeated exposure will assist me being able to tolerate the harsh conditions of the desert while also recognising the signs and symptoms of when I start to boil in my own bag !!

The temperature inside is currently 37 degrees and the humidity is 50%, however conditions in the chamber can be dropped to minus 20. Considering the fact that I have just inserted a small rectal thermometer I think I'm rather upbeat :-) I'm wearing my MdS rucksack packed with food, sleeping bag and water bottles strapped to the front. 

As I step onto the treadmill my core temperature is 37.2 degrees (quite normal) and I start jogging. I opt for a conservative 10k per hour although I'm not sure maintaining this in Morocco will be practical for very long, especially over mountains and dunes. Anyhow I feel good for now so on I plod.Over the next 30 minutes my core temperature is measured regularly and I reach the goal of 38.5 degrees. The Dr tells me this is where we want to keep my body for the best acclimatisation. Its necessary to slow to a jog and I even switch to the bike for a while to allow another runner access to the treadmill. My heart rate is monitored too, on the treadmill is pretty normal but on the bike it jumps up.

Back on the treadmill my temperature is constant however onwards the 50 minute mark I reach 39 degrees and the humidity is at 65%. Even before the Dr tells me this I know my body has changed, I'm somewhat lightheaded and really looking forward to stopping. By the time I stop at just over an hour my core temperature is 39.2 degrees, I've lost 1.3 litres of water through sweat and not drank hardly enough. Over the first 3 sessions I drink 184ml, 330ml and 600+ ml respectively. If I allow this to happen in the desert I'm going to experience dehydration and may fail to finish, with this much water being lost I also need to consider salt replacement.

What have I learnt so far ...

1) I really need to hydrate properly in the desert and I must start this process immediately

2) When my core temperatures elevates and I start to feel it, I need to slow down, rest and take on fluid immediately. This is because the core temperature continues to climb for a while even after you stop.

Its too early to say how the acclimatisation will prepare me for next week however if nothing else I feel more mentally prepared than ever before.





update .....

All 7 sessions now completed. The temperatures reached 41 degrees and the humidity wavered between 20-40%. I'm tired now but feel good for having completed the sessions and I believe I know my body that little bit better.  Apparently my starting core temperature dropped throughout the week and my ability to sweat increased. I took a copy of my figures which I have attached for interests sake. Enjoy.