After a torrid time in the wind again yesterday, the riders are tackling the highest point of the race today the Hoosier Pass at 11,542 feet (higher than any pass in Europe)… as I write Brian is climbing at over 9000ft and 1791 miles in to the race and heading through a long area of wilderness towards the next checkpoint at Towner (pop 22) 2 miles from the Kansas border. Luckily before that is Hot Sulphur Springs that was originally a winter campground for Native Americans who came to use the hot springs for medicinal purposes and has a few more facilities.
Having not heard from Brian today and because I keep waffling on about hydration I thought I’d write a bit about it.
Just being at altitude causes you to lose far more fluids than at lower elevations, the body loses more than 2 pints a day just from breathing. According to the Wilderness Medical Society, you lose water through respiration at high altitude twice as quickly as you do at sea level.
The humidity is lower at higher altitudes so sweat evaporates quickly and you may not realize how much water you are losing through exertion. The lower oxygen levels also make you breathe in and out faster and more deeply, so that you lose even more water through respiration. High altitude can also make you need to urinate more often and can blunt your thirst response, putting you at even greater risk of dehydration.
Not only is dehydration risky on its own, but it can mask or worsen the symptoms of altitude sickness, a potentially life-threatening condition that can affect some people at altitudes higher than 7,000 feet. Dehydration and altitude sickness can both cause nausea, headaches and fatigue. Drinking a lot of water does not help prevent or alleviate altitude sickness. The only cure for altitude sickness is to descend to a lower altitude.
A good way to check if you’re well-hydrated at any altitude is to check your urine. If your urine is dark rather than clear, you are dehydrated and need to drink more. Team Sky even go as far as to have a chart in the bus toilet so that riders can check the colour level.
Also worth noting is it is generally agreed a 1% drop in hydration is about equal to a 10% drop in performance…. (that’s around 1 pint for someone Brian’s size)… above 5% and you are well on the way to dying.