Exercise at Altitude (where the air is rare)

1
Exercise at Altitude(where the air is rare)

• Who performs better at a bike race in San
  Francisco the athlete who trains at altitude, or
  the athlete who trains sea level?
• Why?

2
How high is high? (Dude)

• Moderate lt12,000 ft
• High 12,000 to 18,000 ft
• Very High gt20,000 ft

3
Stress of Altitude

• The 4 Hs
• Hypoxia
• Hypothermia
• Hypoglycemia
• Hypohydration
• Additionally
• Suppressed Immune System
• Suppressed Emotional State

4
Stress of Altitude (Hypoxia)

• O2 at sea level 21
• O2 at 22,000 ft 21
• So why do we not assimilate as much O2 at
  altitude as at sea level?
• Decreased PO2 results in Hypoxia.
• What is PO2?
• How does O2 diffuse into blood and tissues?
• How does PO2 effect this?

5
Acclimatization (adaptation to the new natural
environment)

• IMMEDIATE
• Respiratory
• Hyperventilation
• Body Fluids become more base as a result of
  reduction in CO2 w/hyperventilation
• Cardiac
• Increased heart rate at rest and at submax work
  increased cardiac output
• Stroke Volume remains the same or decreases
• Max VO-2 remains the same

6
Acclimatization

• LONGER TERM (day to weeks)
• Respiratory
• Hyperventilation
• Excretion of base via kidneys and concomitant
  reduction in alkaline reserve
• Cardiac
• Increased Sub-max Heart Rate
• Sub-max cardiac output falls
• Stroke volume decreases (Startlings Law)
• Max VO-2 Decreases (decreased max HR and
  stroke volume)

7
Acclimatization

• Hematological
• Decreased plasma volume
• Increased hematocrit (?)
• Increased hemoglobin
• Increased of RBCs
• Possible increase in capillary beds (?)
• Increased 2,3 DPG
• Increased mitochondrial density
• Increased aerobic enzymes in muscle

8
Acclimatization

• Catecholamine Response
• Nor-epinephrine
• Regulates HR, BP, SV, Vasc Resistance and
  substrate use.
• Increases for 7 days and then stabilizes.
• Epinephrine shows little to no increase

9
Acclimatization (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.

10
Acclimatization (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.

11
Acclimatization 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 altitude
• Active acclimatization
• Move to next camp
• Repeat as necessary
• Summit
• Get outta Dodge

12
Altitude Related Illnesses

• All are exacerbated by
• Speed of ascent
• Altitude
• Health of Individual
• General susceptibility of individual

13
Altitude Related Illnesses

• Slow Ascent Symptoms
• Diminished exercise capacity
• Shortness of breath
• Elevated HR
• Cheyne-Stokes (irregular nighttime breathing)

14
Altitude Related IllnessesRapid Ascent

• Acute Mountain Sickness (AMS)
• Most common alt disorder
• Can appear within 2 hours of ascent
• Headache
• Insomnia
• Irritability
• Weakness
• Vomiting
• Tachycardia
• Breathing problems

15
Altitude Related IllnessesRapid Ascent

• High Altitude Pulmonary Edema (HAPE)
• 12 to 96 hours of ascent
• Can be treated on site but reduction in elevation
  is best

16
Altitude Related IllnessesRapid Ascent

• High Altitude Cerebral Edema (HACE)
• Results from vasodilatation, increased capillary
  hydrostatic pressure.
• Must descend to accurately diagnose and treat.

17
Altitude Related IllnessesRapid Ascent

• Chronic Mountain Sickness (CMS
• Can occur after months or years at altitude.
• Polycythemia
• Genetically linked EPO response to stress.

18
Altitude Related IllnessesRapid Ascent

• High Altitude Retinal Hemorrhage (HARH)
• All climbers experience over 21,000 ft
• Hemorrhage of the macula results in vision loss.
• NOTE Eye Surgery

19
Body Composition and Nutrition

• Muscle Atrophy and weight loss occur at altitude.
• Depressed appetite
• Dehydration
• Increase BMR
• Increased energy output
• EAT, DRINK AND BE MERRY.

20
Body 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
• Pain in the butt to obtain

21
Physical Performance at Altitude

• Max strength is unaffected
• Capacity for repeated contractions is
  progressively impaired
• Endurance is initially decreased but improves
  with acclimatization.
• Decrease motor skills
• Why are track and field records broken at
  altitude?

22
Mental Performance at Altitude (Dumb and Dumber)

• Decreased short term memory
• Where did I park my car?
• Mental Acuity
• Lets see its I before E except after no
  wait its
• Judgment/Decision making
• What in the hell are you thinking?

23
Summary

• 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.
• Reduced PO2 results in physiologic responses that
  improve altitude tolerance.

24
Summary

• 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.

25
Summary

• Acclimatization entails
• Reestablishment of acid-base balance
• Increased synthesis of RBC and hemoglobin
• Improved local circulation and cellular
  metabolism

26
Summary

• 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.