7-Cardiovascular_Pulmonary_fallers-2010
Download
Report
Transcript 7-Cardiovascular_Pulmonary_fallers-2010
CARDIOVASCULAR SYSTEM
• Main transport system
–
–
–
–
–
–
Gases
Food
Waste
Hormones
Minerals
Medications
• Heart rate - controlled by autonomic
nervous system
Specialist PSI Exercise Module
• 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
Specialist PSI Exercise Module
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
Specialist PSI Exercise Module
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
Specialist PSI Exercise Module
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
Specialist PSI Exercise Module
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
Specialist PSI Exercise Module
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)
Specialist PSI Exercise Module
Fallers vs Non-fallers
• Cardiac symptoms can affect falls
–
–
–
–
Syncope
Arrythmias
TIAs
Postural Hypotension
• Cardiac medications not a major risk
except in combination with other
medications (>4)
Specialist PSI Exercise Module
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
Specialist PSI Exercise Module
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
•
Everyday tasks require % of VO2 max
•
Everyday tasks can be performed for longer with greater ease
•
Hypertension and Postural Hypotension in some
Specialist PSI Exercise Module
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)
Specialist PSI Exercise Module
Structure
•
•
•
•
•
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
Specialist PSI Exercise Module
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
Specialist PSI Exercise Module
LUNG VOLUMES
Specialist PSI Exercise Module
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
Specialist PSI Exercise Module
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
Specialist PSI Exercise Module
EFFECTS OF TRAINING
• maximal voluntary ventilation
• mechanical efficiency of movement
• posture
Specialist PSI Exercise Module