Yesterday morning I was hiking a nice, easy trail atop Mauna Kea, Hawaii’s tallest volcano at nearly 14,000 feet, and just could not catch my breath as I hiked up the steep slopes. This mellow hike seemed harder than much more advanced hikes I do in California, where the max elevation is probably more like 2,000 feet. So why the huffing and puffing?
It’s easy to forget that in locations at high altitudes, like the top of Mauna Kea, the partial pressure of oxygen is significantly lower than at sea level. To put it simply, the less pressure on your body, the less gasses that your breathe will impact your body. This can really suck when the gas we’re talking about is oxygen. Whereas at sea level you feel that you’re breathing 21% oxygen (which you are), as you ascend you’ll feel as though you’re breathing less. For example, once your each 10,000 feet, your body feels as though you’re only breathing about 16% oxygen because of the difference in air pressure at that altitude.
So, why talk about this in a freediving blog? Well, even though high altitude makes physical labor more difficult as your body works through the hypoxia, your body also makes changes to adapt. As your body adapts to the lower levels of oxygen, it becomes more efficient working at altitude until you notice the effects of being up at say, 14,000 feet, less and less. These effects can include lightheadedness, muscle fatigue, heavy breathing, elevated heart rate, etc. High altitude climbers will actually hang out at a base camp before summiting their target in order to acquire this sort of adaptation to low levels of oxygen.
But now imagine that after you’ve adapted to a low level of oxygen at altitude, then you return to sea level and perform the same tasks you once did at altitude. Your body will now work WAY more effectively with 21% oxygen, having adapted to running on what felt like perhaps 16%. For us as freedivers this could theoretically be a great way to train. If my body adapts to doing breath-holds at altitude then it would make sense that those same holds would be much easier at sea level.
However, all that being said, they didn’t seem to have any places to rent on top of Mauna Kea, so for now I think I’ll stick to my regular training regimen. Most divers I know don’t actually go to altitude to train, but do use various sorts of altitude-like simulations for training (and of course, with proper safety, etc. employed).
But I’ve always kind of wondered how amazing people like the Tibetan Sherpas that bring people to the top of the Himalayas would be at breath-holding. Hopefully they don’t ever get into it or all of us current freedivers will get our butts kicked.