Exercise at Exercise at Altitude Altitude Who performs better at a Who performs better at a bike race in San bike race in San Francisco… the athlete Francisco… the athlete who trains at altitude, who trains at altitude, or the athlete who trains or the athlete who trains sea level? sea level? Why? Why?
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Exercise at Altitude Who performs better at a bike race in San Francisco… the athlete who trains at altitude, or the athlete who trains sea level? Why?
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Exercise at AltitudeExercise at Altitude
Who performs better at a bike Who performs better at a bike race in San Francisco… the race in San Francisco… the
athlete who trains at altitude, or athlete who trains at altitude, or the athlete who trains sea level?the athlete who trains sea level?
Why?Why?
How high is high?How high is high?• Moderate = <12,000 ft
– Nor-epinephrine• Regulates HR, BP, SV, Vasc Resistance and
substrate use.• Increases for 7 days and then stabilizes.
– Epinephrine shows little to no increase
Acclimatization Acclimatization (Acid Base Balance)(Acid Base Balance)
• Hyperventilation leads to a decrease in carbon-dioxide thus increasing pH of all body fluids. This blunts respiratory control.
• Body begins to excrete base through renal tubules to normalize pH
• This increases resp. sensitivity and allows for greater hyperventilation.
Acclimatization Acclimatization (Acid Base Balance)(Acid Base Balance)
• This decrease in “base” creates a loss of the absolute alkaline reserve inhibiting the bodies acid buffering ability.
• This is made up for by a decrease in acid production as a result of reduced CNS drive, a decrease in intracellular ADP and a reduction in epinephrine output.
Acclimatization ScheduleAcclimatization Schedule• Rapid ascent 0 to 7,500 ft 2 weeks to adjust.• then 1 week per 2,000 ft up to 15,000 ft.
Riiiiight!
Climb to camp altitudeActive acclimatizationMove to next campRepeat as necessarySummitGet off the top!
Altitude Related IllnessesAltitude Related Illnesses• All are exacerbated by:
– Speed of ascent– Altitude– Health of Individual– General susceptibility of individual
Altitude Related IllnessesAltitude Related Illnesses• Slow Ascent Symptoms
Altitude Related IllnessesAltitude Related IllnessesRapid AscentRapid Ascent
• Acute Mountain Sickness (AMS)– Most common alt disorder– Can appear within 2 hours of ascent– Headache– Insomnia– Irritability– Weakness– Vomiting– Tachycardia– Breathing problems
Altitude Related IllnessesAltitude Related IllnessesRapid AscentRapid Ascent
• High Altitude Pulmonary Edema (HAPE)– 12 to 96 hours of ascent– Can be treated on site but reduction in
elevation is best
Altitude Related IllnessesAltitude Related IllnessesRapid AscentRapid Ascent
• High Altitude Cerebral Edema (HACE)
• Results from vasodilatation, increased capillary hydrostatic pressure.
• Must descend to accurately diagnose and treat.
Altitude Related IllnessesAltitude Related IllnessesRapid AscentRapid Ascent
• Chronic Mountain Sickness (CMS)– Can occur after months or years at altitude.
• Polycythemia• Genetically linked EPO response to stress.
Altitude Related IllnessesAltitude Related IllnessesRapid AscentRapid Ascent
• High Altitude Retinal Hemorrhage (HARH)– All climbers experience over 21,000 ft– Hemorrhage of the macula results in vision
loss.
NOTE – Eye Surgery
Body Composition and NutritionBody Composition and Nutrition
Muscle Atrophy and weight loss occur at altitude.
Depressed appetite
Dehydration
Increase BMR
Increased energy output
EAT, DRINK AND BE MERRY.
Body Composition and NutritionBody Composition and Nutrition
• Hypohydration– Increased respirations – dehydration– Low Relative Humidity at altitude– Greater loss in fecal matter– Less absorption in gut– Inadequate fluid intake
• Low desire• Difficult to obtain
Physical Performance at Physical Performance at AltitudeAltitude
• Max strength is unaffected
• Capacity for repeated contractions is progressively impaired
• Endurance is initially decreased but improves with acclimatization.
• Decrease motor skills– What track and field records broken at
altitude?
Mental Performance at Altitude Mental Performance at Altitude • Blood flow to the brain is not compromised• Decreased short term memory
• Where did I park my car?
• Mental Acuity• Let’s see it’s “I” before “E” except after no wait
it’s…
• Judgment/Decision making• What are you thinking?
SummarySummary• As we gain alt the PO2 drops resulting in
inadequate hemoglobin saturation and a decrease in aerobic capabilities
• Ability to perform high intensity short duration (sprint) physical activity is not affected.
• Why not?• Reduced PO2 results in physiologic
responses that improve altitude tolerance.
SummarySummary• Hyperventilation and increased submax
cardiac output via elevated HR are the primary immediate responses to altitude.
• Medical problems may emerge as a result of travel to altitude.
• AMS, HAPE and HACE are the most common conditions.
SummarySummary• Acclimatization entails
– Reestablishment of acid-base balance– Increased synthesis of RBC and hemoglobin– Improved local circulation and cellular
metabolism
SummarySummary• Rate of acclimatization depends on the
elevation. Major adjustments takes about 2 weeks but may require 4 to 6 weeks at higher altitudes.
• Acclimatization does not fully compensate for the stress of altitude as a result VO2max remains depressed.
• Training at altitude provides no more benefit to sea-level performance than equivalent sea level training.