Hydration

                                


           Research suggests that individuals don't drink enough liquids at high altitudes, partially due to a decreased sensation of thirst. Every breath exhaled during exercise at high altitudes means that an individual is losing fluid. Typically, high altitudes tend to have low humidity, which increases dehydrating water losses through the skin. It is crucial that individuals exercising in elevation are hydrating constantly. Even if they do not feel like they are thirsty, their body is most likely thirsty and they must be mindful by reminding themselves to re-hydrate. Some recommendations from the Beverage Institute for Health & Wellness are to:

• Have beverages with every meal and snack.
• Choose beverages that you enjoy.
• Eat more fruits and vegetables.
• Don't only rely on thirst.
• Consume sodium and other electrolytes, along with fluids, during prolonged exercise.
• Follow the American College of Sports Medicine recommendations for fluid intake before, during, and after physical activity. (www.acsm.org)

References

"Climate & Altitude Impact Hydration Needs", The Beverage Institute for Health & Wellness,        2014, <http://www.beverageinstitute.org/article/climate-altitude-changes-special-considerations/>.

"Hydration Checklist", The Beverage Institute for Health & Wellness, 2014, <http://www.beverageinstitute.org/article/hydration-checklist/>.

Images retrieved from:
http://learn.flexport.com/import-water-bottles/
http://www.rei.com/product/867040/nathan-elevation-2l-hydration-vest-mens
                                      

Oxidative Stress

          Researchers believe that exercising in elevation causes a decrease in maximal oxygen consumption because of the decrease in inspired atmospheric oxygen pressure. This then causes oxidative stress. Oxidative stress is the production of free radicals containing unpaired electrons in their outer orbits. This type of stress on the body can cause:

• Damage to cellular membrane
• Increased cellular swelling
• Damage to the cell DNA
• Muscle protein changes which lead to fatigue
• Symptoms associated with DOMS
• A longer recovery time
• Higher rate of injury

           According to ACSM guidelines, individuals exercising at high altitude environments are at great risk as physical and cognitive function decrease. As the workload and progression increase in elevation, the potential for an individual to develop oxidative stress continues to increase.  There is a reduction of the partial pressure of oxygen in arterial blood and at the alveolar level of the lungs. The body tries to compensate to offset this reduction through:

• Increased heart rate
• Increased ventilation rate
• Increased cardiac output
• A shift in the oxygen dissociation curve 

References

Mahady, Thomas P. "Training for Alpine Activities at High Altitude." ACSM's Certifited News,(Indianapolis) Apr.-June 2010, 20th ed., sec. 2: 12-14. www.acsm.org. Web, <http://certification.acsm.org/files/file/CNews20%202_web.pdf>.

Image retrieved from:
http://articles.latimes.com/2012/mar/24/sports/la-sp-mammoth-olympics-20120325

Acclimation

        When traveling to or living in altitudes above 6000 feet above sea level, the body goes through physiological changes due to the decreased levels of air pressure. The air composition does not change as there is still the same amount of oxygen, carbon dioxide, etc. but partial pressure decreases. The oxygen pressure level lowers the rate of oxygen diffusing into the blood and cells – resulting in decreased performance until acclimated. Acclimation requires physiological changes of the body to adapt to the decreased air pressure by progressively exposing the body to higher levels of hypoxia. 

Risks of improper acclimatizing:

• Altitude illness
• Hypoxia
• Decreased performance levels

Hypoxia signs:

• Negative changes in:
• Mood
• Cognitive function
• Psychomotor function
• Decreased reaction time
• Senses change (sight, hearing, taste, feel, smell)
• Increased fatigue

         Achieving acclimation will increase the body’s rate of oxygen diffusion throughout the blood and cells of the body. Pulmonary ventilation will increase within the first week to week and a half of exposure to hypoxia. On the contrary, the same physiological changes do not occur in red blood cell volume – this does not occur until the individual has been exposed to high elevations over approximately 20 days. The red blood cell decrease simultaneously decreases the blood iron volume; therefore, one should take an iron supplement. When the red blood cell content increases to an adequate level, oxygen transfer throughout the body increases efficiency and reduces the individuals’ vulnerability to altitude illness while improving performance.

How to acclimate:

• Progressively increase altitude
• Exercise at a moderate intensity for ~1 hour/day
• Stay hydrated
• Take an iron supplement
• Eat plenty of carbohydrates
• Hydration and carbs will improve blood oxygen content and oxygen transportation in the body

De-Acclimation:

• Occurs within one week of being in lower altitude
• Maintain acclimation performance and physiological changes by periodically exposing self to higher altitude

References

Muza, S. R., Fulco, C. S., & Cymerman, A. (2004). Altitude acclimatization guide., 27 April 2015. 

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