Orthostatic Intolerance and Muscular Atrophy from Spaceflight

1
Orthostatic Intolerance andMuscular Atrophy from
Spaceflight

• Captain Matt Rardon
• Space Mission and Launch Operations
• ASCI 512

2
Introduction

• Orthostatic Intolerance
• What Is It?
• What Causes it?
• Prevention/Treatment
• Muscular Atrophy
• What Is It?
• What Causes it?
• Prevention/Treatment

3
Orthostatic Tolerance

• The ability of humans to maintain consciousness
  upon movement from a supine or sitting position
  to the upright or standing position.

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Orthostatic Intolerance

• Soldiers Heart,
• Irritable Heart,
• Neuro-circulatory Asthenia,
• Dysautonomia

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What Is It?

• Orthostatic intolerance is specifically related
  to the systems of the body that allow cardio
  vascular responses for body position changes.

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What Causes It?

• In just twenty days of bed rest
• 1) plasma loss of 15-20
• 2) total blood volume will drop by 5-10
• 3) decrease in heart volume by 11
• 4) decrease in left ventricular diastolic volume
  by 6-11
• 5) reduced exercise tolerance
• 6) reduced VO2

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OI Treatment

• Initial treatment for orthostatic intolerance
  focused on strenuous isometric and isotonic
  exercises, but it was largely ineffective.

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OI Treatment

• The Russians attempted electrical stimulation of
  the muscles. it was also deemed unsuccessful

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Pharmacological Treatment

• Propanolol
• Atropine

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OI Treatment

• Autogenic Feedback
• Involves training the conscious mind through
  biofeedback to raise blood pressure and heart
  rate.

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Muscular Atrophy

• Significant issue for space travel
• Lack of space in a spacecraft
• Reduced need for isotonic activity will also

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Muscular Atrophy

• After only several weeks in space, an astronaut
  needs help not only walking, but standing.
  Balance problems and postural instability are
  also demonstrated

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Prevention

• Exercise
• Difficult without gravity
• Astronauts must be strapped in or isometrics

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Treatment

• Gene Therapy
• Alter muscle fiber genes to prevent the protein
  breakdown that results in atrophy

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Treatment

• Pharmacological
• Steroids
• Insulin
• Prostaglandins

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Conclusion

• Exercise has limited success in prevention
• Pharmacological means are meeting with the
  greatest success based on research
• Prevention is best
• A mixture of both methods seems the most
  promising future at this point
• Measures must be undertaken to combat skeletal
  muscle atrophy and OI if any long term space
  travel is to be undertaken
• The strength of space travelers will be required
  for normal and emergency operations, in addition
  to general health considerations

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QUESTIONS?