Altitude is our enemy.
Riding 683 miles at seal level is hard enough, try doing it is all between 5,500 feet and 12,095 feet. I arrived in Durango, Colorado on Friday. We were staying in the students`residences of Fort Lewis College. We slept and ate at 6,850 feet. We hadn’t done any hard riding yet but we could all feel the effects of altitude. Here`s your crash course on what I am talking about:
“As you climb above sea level, atmospheric (barometric) pressure drops with a parallel decrease in the amount of oxygen available at the blood/air interface in the lung alveolus. Hypoxia (a low blood oxygen level) results and limits the maximum amount of oxygen that can be delivered to the muscle cels to support aerobic physical work. Although the heart rate (and cardiac output) increase to deliver more blood (with less oxygen per ml) to the muscle cell, complete compensation does not occur and the maximal aerobic ability (VO2 max.) is reduced by approximately 1% for every 100 meters (~ 300 feet) above 4500 feet. This change can be measured in the performance of highly trained athletes at altitudes as low as 1500 feet above sea level.
The body implements a number of adaptive changes (acclimatization) which include a higher ventilation (respiratory or breathing) rate and a higher blood lactate level for any level of submaximal exercise to offset the lower blood oxygen levels as the elevation above sea level increases. Both of these increase an individual’s sensation of dyspnea (shortness of breath) and fatigue. Acclimatization responses begin immediately and may take 4 to 6 weeks to reach their maximal effectiveness – specifically an increase in red blood cell mass.
In addition to a decrease in maximal aerobic capacity, the symptoms of acute mountain sickness (AMS) affect, to varying degrees, all travelers to elevations greater than 5280 feet. In a small percentage of those climbing to this altitude, AMS can lead to high-altitude pulmonary edema (HAPE) and/or high-altitude cerebral edema (HACE). Symptoms of AMS range from a combination of headache, insomnia, anorexia, nausea, and dizziness, to more serious manifestations, such as vomiting, dyspnea, muscle weakness, oliguria, peripheral edema, and retinal hemorrhage.
Although the primary cause of symptoms at altitude is the reduced oxygen content (of the air and as a result the blood) at high altitudes, the physiologic pathway leading from hypoxemia to AMS (and its sequelae) remains unclear. Tips on self-diagnosis and symptom recognition are critical elements to include in educating those who are contemplating a trip to high altitudes.
The most immediate response to altitude is the hyperventilation that occurs in response to the decrease in blood (arterial) oxygen levels (a significant symptom above 2000 meters). This increased respiratory rate can remain elevated for up to a year at altitude. The degree of this hyperventilation response varies from individual to individual – those with a strong hypoxic drive will perform exercise tasks better at altitude than those with a blunted ventilatory response.”
Fun stuff. Imagine, I never nap in the afternoon and I have already had two afternoon naps in two days.
And do the math: 12,095 feet minus 4,500 divided by 300 feet equals: 25.3% less power on top of Indepedence Pass than where I normally ride.
The one good thing about the USA Pro Cycling Challenge compared to the Tour of California is that the morning transfers are shorter; therefore we get to “sleep in” until 5:00 am. On the flip side of the coin, everything is more difficult here: riding, breathing, sleeping and recovering.
We all had breakfast at 6:00 am and started to ride at 7:00 am. The group quickly split into two groups and by the time we got to Telluride about 110 miles later we had four groups on the road. Everyone seemed pretty happy with their day and extremely happy to find a bed. After a team meal and meeting we all went to our room at 8:00 pm and the consensus was: “I’m going to sleep.”
For map and profile of Stage 1 please click here.
To watch a video about Stage 1 please click here.
Starting the 2012 USA Pro Challenge with a road race instead of 2011’s Prologue means the competition is wide open starting on the first day. Often an opening road stage can be tame, but this is anything but, with challenges coming nearly right away. Starting with a 5 mile loop that encompasses most of town, and the Tour’s first Sprint Line of 2012, the riders head up hill and out of town past Fort Lewis College and toward Telluride. After a second Sprint Line in the town of Dolores, racers will start a gradual canyon climb that lasts more than 30 miles, eventually taking them up and over Lizard Head Pass at 10,222 feet. After the climbers’ first test of the week they take a 15 mile descent into the narrow streets of Telluride to finish stage one and the first 125 miles of the race. Total climbing: 9,238 feet.