Transcript 7-Cardiovascular_Pulmonary_fallers-2010

CARDIOVASCULAR SYSTEM
• Main transport system
–
–
–
–
–
–
Gases
Food
Waste
Hormones
Minerals
Medications
• Heart rate - controlled by autonomic
nervous system
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• Circulation
–Pulmonary (to lungs)
–Systemic (to body)
–Coronary (to heart
muscle)
• Blood vessels “tubes”
–Arteries - from heart to
body
–Veins - from the body to
the heart
–Capillaries - interchange
of gases, food and waste
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CONTRACTION OF HEART MUSCLE
• Heart muscle contracts automatically – spontaneous
discharge of pacemaker cells
• Sino-atrial node - heart’s pacemaker located in right
atrium. Impulses travel through atria to ventricles via
A-V node.
• Heart muscle cells are connected
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CONTRACTION OF HEART
•
Parasympathetic activity slows the heart
• vagus nerve releases Acetylcholine
•
Sympathetic activity quickens the heart
• release of Adrenaline and neurotransmitters
•
Blood Pressure
• cardiac output flowing into vascular system influences systolic
pressure
• resistance of blood vessels influences diastolic blood pressure
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VOLUMES
•
Stroke Volume
• Blood per beat
•
Cardiac Output
• Blood per minute
•
Maximal O2 Uptake
• Amount of oxygen that can be used in one
minute – ml/kg/min
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40
Men
% VO2 max
100
Maximal Oxygen Uptake (ml/kg.min)
75
Stair Climbing
(slowly)
20
50
25
Walking
(3mph)
% VO2 max
100
Making the bed
75
Dressing
50
25
0
0
30
Age 
80
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EFFECTS OF AGEING
At rest no major changes to heart rate, stroke volume
or cardiac output due to age alone BUT when the
system is challenged then there are age-related
deficits – compounded by sedentary behaviour
•  stiffness of heart wall (collagen)
•  Maximal H.R.
•  Maximal stroke volume
•  Maximal cardiac output
•  Maximal aerobic power – 10% per decade
•  systolic blood pressure
•  incidence of postural hypotension (failure of venous return)
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Fallers vs Non-fallers
• Cardiac symptoms can affect falls
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–
–
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Syncope
Arrythmias
TIAs
Postural Hypotension
• Cardiac medications not a major risk
except in combination with other
medications (>4)
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FUNCTIONAL CONSEQUENCES
• Tasks will require  % of maximum in older person
• Unable to sustain submaximal activities
• Postural hypotension can lead to blackout / drop attack /
injury
• Fartlek training approach
• Circulation re-booster on major postural transitions
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EFFECTS OF TRAINING
•
Increased time in Diastole ( heart health)
•
Maximal aerobic power can be  by 
– Muscle oxidative enzymes
– Muscle capillarisation
– Stroke volume and cardiac output
•
Relative increases similar to young people
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Everyday tasks require  % of VO2 max
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Everyday tasks can be performed for longer with greater ease
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 Hypertension and  Postural Hypotension in some
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PULMONARY SYSTEM
• Main transport system for gases
– Oxygen
– Carbon Dioxide
• Ventilation controlled by Nervous
System
– normally automatic (respiratory centres in
brain stem)
– some voluntary control (cortex overides
respiratory centres)
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Structure
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•
•
•
•
Nasal passages
Larynx
Trachea
Bronchi
Bronchioles
• Terminal Bronchioles
• Alveolar Ducts
• Alveoli
•
Gas exchange takes place
rapidly in alveoli - large
surface area surrounded by
dense capillaries
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VENTILATION
Inspiration is
active
volume of thoracic
cavity  by
contraction of
intercostal muscles
and diaphragm
Expiration (at
rest) is passive
volume returned to
resting values
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LUNG VOLUMES
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EFFECTS OF AGING
•  Stiffness of chest wall
•  Strength of respiratory muscles
•  Elastic recoil in lung
•  Residual dead space
•  Functional area of lung
•  Cartilaginous support
•  Thickening of mucosal lining
•  Sensitivity of respiratory centres
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FUNCTIONAL CONSEQUENCES
System still adequate for sub-maximal activity
•  Respiratory work
•  Oxygen costs of many activities
•  Breathlessness may reduce tolerance of
exercise
•  maximal voluntary ventilation
•  mechanical efficiency of movement
•  posture
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EFFECTS OF TRAINING
•  maximal voluntary ventilation
•  mechanical efficiency of movement
•  posture
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