Last year, an altitude chamber opened in my local town. Altitude chambers have been growing in popularity as athletes strive to find an extra edge to their training. In this case, it is a mobile unit that creates a training environment that is low in oxygen and simulates the feeling of training at high altitudes.
In December, one of my fellow club members won his age group in an Ironman 70.3 race by a whole hour. He felt very strongly that his training in the chamber had had a massive impact on his fitness and training. Over the coming months, more anecdotal stories appeared on Facebook reporting the fitness and speed benefits of training in an altitude chamber and I started to look into it a bit more closely.
In the sports physiology world, the benefits of intermittent exposure to exercising in a low oxygen environment (known as intermittent hypoxic training or IHT) has been met with mixed reports. There are many studies which tell us about the increase in red blood cells that occur if we train at high altitudes for weeks or months, but there is actually very limited data on the effects of intermittent exposure in a chamber such as this one.
On searching more deeply I found some studies in this area and there is growing evidence of the benefit of IHT on certain types of exercise, particularly exercise involving sprinting. It appears to show that the low oxygen puts increased stress on the muscles and encourages adaptations to the muscles and improved blood flow. It may also help to delay fatigue of peripheral muscles. There is much more research needed, mostly because all the papers examined used very small numbers of athletes. However, the overriding feeling now is that IHT is likely to be beneficial in terms of a fantastic addition to your training regime with each session adding more value to your training than the equivalent session outside.
So, with 12 weeks before my A race, I decided to sign up for a 10-week training package with Altitude WA. The chamber isset to an altitude of 3300m with an oxygen level of 14% (normal levels being 21%). During my first session I was asked to record my blood oxygen saturation via a finger monitor while my heart rate was in different training zones. I discovered that I was working with an oxygen saturation of 84% to 94% depending on my training zone (normal levels being 98-99%). This helped to work out where the best benefits would be found while training.
Each session lasts 45-60 minutes and follows a cycle-based workout on the large screen at the front of the chamber. Beside the screen are monitors with my heart rate, my training zone and the oxygen levels in the chamber. The workouts are set according to heart rate and usually involve a variety of sprints or sustained sub-maximal efforts. I did 2 sessions per week over a 10-week period.
It was hard to know if I was gaining any benefit as I was doing lots of different races which made it hard to compare my performance, but in general I was feeling strong and started to see some improvements while training. I was seeing improvements in my cycle sprint ability, my running endurance and most interestingly, also in my swim.
By week 9, I decided it was time to put this to the test and repeat our local Parkrun. This is a good repeatable 5km run, which makes it a useful comparison. I had never been able to get below 22 minutes for this run. I felt as though I was pushing hard, but felt comfortable throughout the run. I stopped my watch at the end and had to double-check as I saw 20:57 staring back at me.
As for my A race? I have 2 weeks to go…
About the author: Natasha Pertwee is a Team GB triathlete who moved to Australia.