But this protocol takes a significant chunk of time, requiring you to accumulate to hours at altitude — which usually works out to a period of at least 20 days.
Your body can and does begin to adapt to the new altitude in less time. For example, in a narrative review published in a issue of Frontiers in Physiology , researchers describe the habit of European coaches using slightly shortened stays at higher altitude 10 to 14 days , based on empirical evidence that these trips benefit their athletes. They also note that physiological adaptations to higher altitude nearly plateau after a two-week acclimatization period.
And in a issue of the International Journal of Exercise Science , researchers related their studies of a very small group of volunteers eight people in a day altitude training camp. They stated that cardiovascular changes can occur at altitudes as low as 1, meters about 6, feet , and in as short a period as 10 days.
Of course, even a day to two-week stay won't be within the reach of many athletes — especially if you're paying your way to run in a recreational race. The authors of the Frontiers in Physiology review go on to recommend that if you only have access to altitude for a very short period before your competition, one of the better approaches may be to arrive the day before the competition and check out the course, then sleep at low altitude before returning to altitude the next day.
This is based on findings from another study that was originally published in , but was republished in a November issue of the Journal of Applied Physiology. In the newest publication, the authors note a new, noteworthy conclusion that "athletes who cannot arrive at altitude with adequate time for complete acclimatization can choose the short-term arrival strategy that best fits with the logistics of their travel.
Have you noticed the conditional language — may, might and so on — being thrown around? That's because, again, each person has a distinct individual response to increases in elevation, and exercise researchers are still hunting for the ideal solution to shorten the required acclimatization time and improve performance for visitors to a higher elevation. Even if you can't set yourself up for a two-week training camp in advance of your race, there are some tangible measures you can take to help yourself adapt to your new elevation before the event begins.
The first is planning your schedule to allow yourself adequate rest time, both during your trip to the new locale and in the day s leading up to your event. Although scientists still haven't deciphered the deepest mysteries of exactly why or how, they acknowledge that getting enough sleep can have a profound effect on your body's performance. Along the same vein and working under the assumption that you'll fly to reach your destination, the second very tangible thing you can do is shift your schedule beforehand to minimize jet lag.
If you spend less than a day or two at altitude say, on a moderate climb of a peak like Baker or Rainier, where most people return to sea level within 24 hours of reaching the summit , your body will not have had enough time to permanently adapt to the altitude. The composition of the blood changes after about 2 weeks of altitude exposure by producing more red blood cells and hemoglobin the iron-protein compound that transports oxygen 3 but most people climbing peaks in the Pacific Northwest are only exposed to elevation for about days at a time.
Training acclimatization time needs to be longer as the altitude becomes higher. Training for 14 days at or above 6, feet as at the U. Olympic Training Center in Colorado Springs and 28 days at or above 8, feet are currently the best recommendations for athletes wishing to compete at similar elevations, while complete adaptation to the extreme altitude of 13, feet is possible after a continuous stay for 14 months 3. Obviously, climbers have a tiny fraction of this time open to them.
Baker 10, ft or Mt. Adams prior to your ascent of Mt. One study cited by Armstrong indicates that the red blood cell volume of high-altitude natives people who spend most of their lives above ft decreases as quickly as ten days after spending time at sea level. These adaptations not only affect our respiratory system, but we also see changes in our cardiovascular and metabolic systems over time. These adaptations include, but are not limited to increased ventilation, increased red-blood-cell mass, decreased sensation of effort, improved metabolic efficiency, and possible improved running economy, the last of which may occur for reasons which remain unclear 3.
The most immediate response your body has to altitude exposure is a decrease in your blood volume. This is known as haemoconcentration. This phenomenon may be why you often feel really good during your initial run at altitude before you start to feel the effects of your body trying to make more substantial adaptions 24 hours later.
During this time, you will also experience a brief increase in your resting and submaximal cardiac output. Think of this equation as the work load your cardiovascular system manages. During the first few days at altitude, your stroke volume decreases as a result of the initial drop in blood-plasma volume. However, after a few days and as your body becomes more efficient at extracting and delivering oxygen, your cardiac output and heart rate begin to normalize at rest and during aerobic activity 3.
However, at high altitudes and for a longer period of time, maximal heart rate and stroke volume at highest intensities are often blunted. It is because of these changes that are rapidly taking place that we generally feel terrible 24 hours to 72 hours after arriving at altitude. There is a marked decrease in endurance-running performance with an increase in altitude 5. Another of the first changes that occurs when you arrive at higher elevations is in your ventilation rate, which might leave you feeling short of breath while running.
These changes to your ventilation rate and depth, where you ventilate more and more shallowly, are known as hypoxic ventilatory response HVR 2.
However, this increase in ventilation causes a cascade effect with more CO2 than normal expired, which can lead to hypocapnia, or lower-than-normal CO2 in the blood, and eventually respiratory alkalosis, a pH imbalance in the body 1. Our bodies have a finite window of pH tolerance, and when we begin to experience a pH increase during hypoxia, our kidneys respond and correct the pH shift via renal-compensation mechanisms. The primary mechanism for countering this is diuresis, or more urination.
Additionally, during this same time, there is an increased release of erythropoietin EPO 2. EPO may sound familiar to many of you as an illegal performance-enhancing drug of choice, particularly in road cycling, to boost red blood cells. A shift in blood-oxygen levels creates a cascade of reactions leading to the kidneys producing and releasing erythropoietin EPO , which, in turn, stimulates red bone marrow to produce more red blood cells 6.
The increased diuresis at altitude is called hypoxia diuresis response HDR. HDR occurs in response to HVR because during that increased time of ventilation and increased body pH, the body starts to also increase its excretion of sodium and bicarbonate ions in your urine and retain more hydrogen ions in your body to try to shift you back toward equilibrium 2.
This is also one of the ways the body creates the haemoconcentration I mentioned earlier, decreasing your blood volume by offloading fluid through increasing urine output. The downside of this is that, as an athlete, you are at an increased risk of dehydration through excessive fluid loss via urination and decreased fluid intake due to decreased thirst while at higher elevations, a phenomenon that is not fully understood 1.
Another trick our kidneys perform while exposed to high altitude is to produce and secrete more EPO into the blood stream. EPO triggers erythropoiesis, the process of creating new red blood cells in your bone marrow. Although EPO is released into the bloodstream in the first few hours of altitude exposure, erythropoiesis takes at least one week but as much as two to three weeks to allow the red blood cells to mature and become fully functional 9.
This is what is ultimately responsible for your blood-plasma volume returning to normal and then ultimately increasing to above baseline. Along with the increase in red blood cells, there is an increase in hemoglobin, the red, iron-containing, oxygen-transport protein found in red blood cells.
This increases both the oxygen-binding and oxygen-carrying capacity of our blood. Basically, 2,3-DPG is a compound that encourages the release of oxygen from hemoglobin to tissues that need it the most. It does this by binding to hemoglobin in a special way that encourages it to release its already bound oxygen instead of picking up more, delivering oxygen to tissues more quickly.
Historically, research has suggested that the minimal elevation required to stimulate EPO release is 6, to 8, feet 2, to 2, meters above sea level but more recently there is evidence that chronic exposure 21 days to 5, feet 1, meters was enough to stimulate hematological changes while chronic exposure to 5, feet 1, meters was not enough 15,13, A summary of system-wide acute and chronic, or short-term and long-term, adaptations to altitude exposure 2.
There are two major cellular-level changes that take place when we are exposed to altitude. Hypoxia-inducible factor-1 HIF-1 and heat shock protein 90 HSP90 help our bodies achieve cellular tolerance to ascending to high elevations 4. HIF-1 is thought to be the key genetic influencer in many of the adaptations that are part of altitude acclimation. In fact, not only does HIF-1 play a role in stimulating cells that are responsible for EPO production, as mentioned previously, it also activates genes responsible for angiogenesis creating new blood vessels , the upregulation of glycolysis the breakdown of glucose , and it also coordinates iron uptake and delivery to the bone marrow for increased hemoglobin production 1,4.
I mentioned heat shock proteins briefly in my article on heat acclimation , but essentially HSPs are molecular chaperones that provide the maintenance and clean-up of damaged cells and proteins from a multitude of different sources, including heat exposure 7. Heat shock proteins, in particular HSP90, capture and refold denatured proteins, which protect cells from future thermal damage.
It turns out that HIF-1 continuously degrades, or becomes defunct, in oxygen-normal environments. Generally speaking, HIF-1 stabilizes with altitude exposure and works properly. What is really interesting here is the potential exercise physiologists see in stimulating and controlling HIF-1 via a different modality aside from altitude.
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