Seattle from Denver(Travel)

So I have landed back in Seattle. After traveling on the highways of Wyoming and Montana, speed limit 75 mph, coming into the Seattle Metro area, speed limit 60 mph, was like slowing time. No wonder Seattle is an hour behind, Einstein coined it right stating that as speed slows, time slows. The only constant is the speed of light and they let you travel the speed of light in Montana. I still got two speeding tickets though, one in Wyoming and one in Montana. I think they may be in budget meltdown since I've never heard of the Montana Highway Patrol. I think they just threw one together for the Thanksgiving weekend.

Music on the road included Marcy Playground, Muse, Chopin, U2, Radiohead, REM, AC/DC, Roxy Music. I also listened to XM radio which turned out to be quite cool. I could listen to real news like CNN, NPR or BBC or I could listen to conservative talk radio. I tried to call into a show both ways. On the way out to Denver the mountains prevented me from getting on air and on the way back from Denver the guy on the radio kept asking for callers but when I called the number listed I only got a voice message for his show.

From Denver to Seattle I stopped in Cheyenne, WY, Bozeman, MT and Spokane, WA. Bozeman was a hoot again. I had drinks with the daughter of a commodities broker, she was moving to London to study economics, and an environmental economist as well as a barber and a salesman from Georgia. They all loved Montana and hoped no one would move there. Right!

In Wyoming I ran into a couple of statues on cliffs. There was a cowboy on horse statue near Casper and just before Montana there was a statue of a Jackelope, the dreaded cross between a rabbit and an antelope. A rabbit with antlers. They are the menace of the West and leave carnage in their wake. Many believe that the Sioux weren't even at the Little Big Horn that day...that the Jackelope were.

Some other thoughts that I had on the road...uhh...

All for now. Hope to have something out on the history of TB soon.

Hiking at 12,000 ft. What was happening to me?(Medicine)

Burly men walking a burly trail? Not usually my style, but sometimes I have to do what burly men do----burly things. I'm also not one to resist peer pressure all the time. My friend Tim and I went to Rocky Mountain National Park for a hike this week-end. I'm on the left and Tim on the right. We were serious hikers today and without smiles because we were tired. Not as wiped out as those that climb Mount Rainier or Everest, or those in-between, but for a day going from 5ooo ft. of altitude in Denver to 12,000 ft. at our highest and 8 miles of walking we had trouble mustering smiles. But we actually had a great time.

I'll take some time to reflect on what happened to us being interlopers to altitude. It all revolves around oxygen. Ultimately, oxygen in the air depends on the pressure of the atmosphere where we are. At sea level the atmospheric pressure is 760 mmHg, the pressure it takes to move a column of mercury 760 mm. As one goes higher the atmospheric pressure(Patm) falls: at 12,000 feet it is 63.5% of pressure at sea level, or 483 mmHg (thanks Google). The air is lighter. Since the pressure of oxygen in the air is about 21% of the atmospheric pressure there will be less oxygen as one goes higher, at sea level the pressure of inhaled oxygen(PiO2) is about 150 mmHg and at 12,000 ft. it is only 101 mmHg. This is getting scary already. But on Mount Everest where the Patm is only 272 mmHg the PiO2 is only 57 mmHg. Yikes. People pass out and die when the PiO2 is about 40-50, there is no way your body can compensate. But people climb Mount Everest, and in Rocky Mountain National Park, all the time and do OK, though, some fair better than others based on their genetics. What happens in the body to allow oxygen to get to tissue so one doesn't crumple into a ball of lifeless meat?

Firstly, we breath more. Ventilation is defined by the amount of carbon dioxide (CO2) our bodies can blow off and we do it by breathing. Normally we breath about 5 liters of air in and out of our bodies every minute. This delivers O2 into the body and blows CO2 out. By breathing deeper and more rapidly we get more oxygen in but we also get more carbon dioxide out. Since CO2 takes up space in the air sacks of our lungs (alveoli), by breathing more we can make space for O2 by getting rid of more CO2. When we are at altitude cells in the carotid arteries sense low O2 and send a signal to "breath" more to our diaphragm and the muscles between our ribs. Our bodies can generate about 25 liters of air movement, compared to 5 liters at rest, when we are healthy but stressed by exercise and/or high altitude.

In addition to more air moving in and out of the lungs the area that receives ventilation in the lungs becomes more coordinated with blood flow to the lungs. The lungs become better at a directing blood flow to areas that receive ventilation and this is called ventilation and perfusion matching. In essence there is less wasted blood flow to the lungs.

When one goes to high altitude the stress response occurs which releases adrenaline. This adrenaline in addition to low oxygen contributes to changes in the heart that allow for more delivery of oxygen to the tissue. The heart starts to beat more vigorously by pumping more blood with each beat and the heart rate increases leading to more heart beats each minute. The Cleveland Clinic also showed recently that the blood vessels near the organs may dilate from increased production of a chemical called nitric oxide.

Finally, there may be changes that occur in the blood. In the setting of hypoxia the red blood cells produce more chemical called 2,3 DPG which changes the nature of hemoglobin molecules allowing them to drop off more O2 at tissue than they would normally. Over days the red blood cells become more numerous as well.

But with all the changes that occur in the body as we are exposed to altitude we still lose our ability to exercise the higher we go. One resource I read suggests that we lose about 3.5% of our ability to exercise for every 1000 ft. above 5000 ft. that we go. And despite other adaptive changes that occur over time athletes can not perform at the level of exertion that they can at sea level. So even the most in shape and adapted person can still only barely move one foot in front of the other slowly while climbing Mount Everest.

So our exhaustion after climbing at 12,000 feet came despite our bodies attempts to adapt to the high altitude. In some ways humans were never well adapted to high altitudes compared to some animals since we know that some birds can fly at 30,000 feet as they migrate between the Tibetan plains and India, soaring easily above those climbers of Mount Everest in flocks that embarrass us humans. But they have a completely different mechanism for breathing which includes a more efficient counter exchange system that doesn't require the effort that humans have to do to move air in and out of their lungs. Birds store air in their bones and their counter exchange system is continuous, like water flowing through the cooling system of our car.

To end I would like to show you how abnormal breathing can be on Mount Everest by showing you arterial blood gases from climbers published in the New England Journal of Medicine this year, 2009-volume 360-page 140. Normal pH in the blood is 7.4, on Everest it was 7.53: normal carbon dioxide pressure is 40 mmHg, on Everest it is 13 mmHg (the climbers blow CO2 off making room for what little O2 is available: and normal O2 in the blood is 90-100 mmHg and on Everest it was 25 mmHg.

Obviously I haven't been able to review all that is known about changes in the body that occur when hiking or climbing, or living, at altitude but it seems that we are best adapted to stay low. Climbing mountains pushes the limits of human physiology.

Vail, CO and halloween with the locals