During an intervals session in Regent's Park several weeks ago I tore my right calf muscle. In medical parlance it's apparently known as a Grade 2 strain but it's a tear.
I gave it two weeks off and then feeling better went out running in Hampstead Heath one Tuesday morning....POP! It went again, damn.
3 more weeks passed and just when I thought I was back to normal, POP! in the middle of Vondel Park in Amsterdam. At this point I am only 5 weeks away from the Sahara Desert and the doctors are calling for 6 weeks of rest. Try as I may, the math just doesn't seem to work out, but I will give it my best.
I've hooked up with the Altitude Center here in London which has been allowing me to use it's hypoxic chamber to mimic the effects of training at high altitude and with lower oxygen pressure. Originally I was going to use the center for an upcoming race in the French Alps however now it is actually allowing me to get my heart rate up with low impact and low intensity. This could be my saving grace but we shall see.
Below is a blog that I wrote before the Atacama Crossing earlier this year which took place at 11,000 feet. It explains the effects of altitude and the impact of training at high altitude.
February 2010
At 6pm yesterday afternoon it was still a sunny 88 degrees (31C) here in San Pedro de Atacama and time for a run. After 50 hours of being sedentary I couldn't think of a better way to rid myself of the mystery meat sandwich toxins and travel 'grease'.
Turning right out of the Kunza Hotel led me directly into....a pack of goats. Yep, a pack of goats. All I could think was that here I made it through two days of travel through an earthquake stricken country and I end up trampled to death by goats. Surviving the goats I continued on down a long dusty stretch of narrow road bordered on either side by walls of mud and straw and canopied by the branches of chañar trees. The road veered around to the right and after about 6 minutes opened to a dry river bed and a wide expanse of desert landscape. It wasn't until after hurdling from one side of the river bed to the other and then scrambling up a fairly steep sandy incline that I noticed it.
The Altitude. Like the unwanted guest at a party that you know will be there but whom you hope you can just avoid for the evening. Well, in this case when it was my turn to talk to him he just walked up, punched me in the chest, and left me gasping for air.
The common myth is that a decrease in the amount of oxygen acts as the driver for all types of altitude sickness. The true cause, however, is the lack of atmospheric pressure. Because of this, the air molecules are much more dispersed, so there is actually much less atmosphere up here (also contributing to the significant risk of sunburn), not just less oxygen! There is actually the same concentration of oxygen in the atmosphere regardless of elevation. As a result, reduced pressure does not allow as much air into your lungs, which can therefore not absorb as much oxygen as your body needs.
Now, what that essentially means is this: As the body notices that it is receiving less and less oxygen, it attempts to compensate by increasing the amount of blood flow to the brain. That's why when you're up here you feel your heart fluttering in your chest as though it wants to get out.
Picture your body as a car. I'm probably the equivalent of a Toyota Corolla and should be recalled but that's for another time. Imagine your heart rate measure in BPM (beats per minute) as the equivalent of the RPMs in your car. Also imagine the amount of oxygen that flows through the blood in your heart as the equivalent of gasoline flowing through the engine in your car. As you push the accelerator to go faster you push more gasoline through the engine and the RPMs go up. If you 'redline' your car or push the RPMs as far up as they can go to somewhere like 6,000 or 7,000 you will go faster, however you will get terrible mileage per gallon and you'll run out of gas a lot faster than someone driving at their optimal performance rate of around 2,000 to 3,000 RPMs. Chances are good that you will probably also do some significant damage to your engine.
You can calculate your heart's 'redline' or Maximum Heart Rate by subtracting your age from 220. Bad news for any of my friends turning 220 this year. In my case, my Maximum Heart Rate is 187 or (220-33). You can calculate your 'optimal performance zone' or Target Heart Rate by multiplying your Maximum Heart Rate by 0.6 and again by 0.8. This gives you your 60%-80% Target Heart Rate zone for optimal performance. Again, in my case I aim for somewhere between 112 BPM and 149 BPM.
If we get back to my run yesterday what this all means is that while running at a pace that would typically keep me in my Target Heart Rate zone I was feeling the affects of running near my Maximum Heart Rate. I was only running at a 7:30 minute per mile pace yet my heart was racing in between 170-177 BPM which is where I would typically be if I pushed to 6:30 or 6:45 minutes per mile. My breathing labored searching for oxygen and I eventually lowered my pace to around 9:00 minutes per mile where I suddenly felt comfortable however still pushing 155 BPM.
Physiologically, when traveling above 2500m (8,200ft), there are other factors to keep in mind such as the risk dehydration and AMS, or acute mountain sickness. As your heart beats faster it pushes through more and more water meaning that hydration is a key to warding off altitude sickness. If the heart overcompensates, and there is too much blood flow to the brain, a process begins causing the brain to swell resulting in several symptoms like headaches, fatigue, and nausea.
The good news in all of this is that the body is an amazing and resilient organism. Steadily the body starts to produce more and more red blood cells which increases the thickness of the blood and ultimately aids in the delivery of oxygen. If we go back to our car example, this would be the equivalent of flushing out the nasty watered down gasoline that you bought from that truck stop in Tennessee with the higher octane good stuff.
Over the next two and a half days, this is essentially what I will be attempting to do. The highest point in London is Primrose Hill sitting an imposing 260 feet above sea level so I've got the blood equivalent of gasoline from that Tennessee truck stop.
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