stress adaptation and exercise
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Stress Adaptation and
Exercise
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Stress
Nonspecific response of the body to any
demand placed on it.
Stressors, stress producing factors It may be pleasant or unpleasant and
induces different emotional or
psychological responses while eliciting
similar physiological reaction.
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The Stress response
Eustress, positive stress; Distress,
negative stress
It elicits the General Adaptation Syndrome(GAS; the syndrome of just getting sick)
Enlargement of the adrenal glands, sympathetic
stimulation
Fatigue, malaise, loss of appetite, gastric upsetand other nonspecific complaints
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General Adaptation Syndrome
Alarm Stage
Stage of Resistance
Stage of Exhaustion
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Alarm Stage
Initial stimulation by a stressor hypothalamic
stimulation (release of CRH) pituitary
stimulation (release of ACTH) adrenal glands
release glucocorticoids (cortisol)
Sympathetic stimulation (fight-or-flight
mechanism) release of catecholamines
(epinephrine, norepinephrine) vasoconstriction
of the skin, GIT, kidneys; vasodilatation` of heart
vessels and skeletal muscles increase in heart
and respiratory rate; increase in blood pressure
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Alarm Stage
Sympathetic stimulation (fight-or-flight
mechanism) release of catecholamines
(epinephrine, norepinephrine)
vasoconstriction of the skin, GIT, kidneys;
vasodilatation` of heart vessels and
skeletal muscles increase in heart and
respiratory rate; increase in bloodpressure
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Stage of Resistance
Increase in blood sugar levels immune
suppression due to circulating excess
corticosteroids
delayed healing
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Stage of Exhaustion
Resistance to the stressors are depleted
and death ultimately occurs
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Local Adaptation Syndrome (LAS)
Local Adaptation Syndrome (LAS)
Localized reaction to stress
Similar to GAS but exhaustion lead to ageneralized response
Ex. Inflammation
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Physiologic Response to Stress
Neurologic Mechanisms
Motor nervous system (voluntary) and
Autonomic nervous system (involuntary)mediated via the sympathetic nervous
system
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Neurologic Mechanisms
Epinephrine and
Norepinephrine
Peripheral vasoconstriction
(skin, viscera, kidneys)GI motility and secretion
Vasodilatation of skeletal and
cardiac muscles
Bronchial dilatation Rate and force of cardiac
contraction
Glycogenolysis and
gluconeogenesis by the liver
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Endocrine Mechanism
Effects of Glucocorticoids
More fuel is made available for energy via
increase in gluconeogenesis,glucogenolysis, lipolysis and protein
catabolism
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Endocrine Mechanism
Suppresses the inflammatory response
Stabilizes lysosomal membrane which
decreases release of proteolytic enzymes
Decreases capillary permeability
Suppresses the immune system
Blocks interleukin 1
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Stress-Induced Disease
Cardiovascular disease
Coronary artery disease ( Atheroscelrosis)Hypercholesterolemia
high fat diet, stressful living conditions, personality
and genetics
AnginaEmotional stress
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Stress-Induced Disease
Immune Deficiency
Excessive glucocorticoids
Physiologically and psychologicallystressful events precipitate a decrease in
lymphocyte and leukocyte activity
It is detrimental in certain conditions
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Stress-Induced Disease
Gastrointestinal Diseases
Stress ulcers due to gastric mucosal
ischemia and acid secretionDuodenal ulceration (H. Pylori)
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Stress-Induced Disease
Cancer
Increase in the production of abnormal
cells Inability of the body to destroy abnormal
cells
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Exercise
Physical exercise is essential to health
It promotes cardiovascular and other
systemic adaptaion to maintain physiologicfunction
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Effects on the Cardiovascular System
Heart Rate (HR)
Sympathetic stimulation of the autonomic
nervous systemRelease of epinephrine and nor
epinephrine
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Effects on the Cardiovascular System
Heart rate increases (maximal heart rate)
Influenced by age, gender, level of fitness,
pre-existing diseases, altitude, type ofexercise and true maximal exertion
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Effects on the Cardiovascular System
Stoke Volume (SV)
Amount of blood ejected from the ventricle
per each heartbeatFactors responsible for SV are venous
return, ventricular distensibility, ventricular
contractility, systemic and pulmonary
resistance
Resting SV range from 60 to 100ml
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Effects on the Cardiovascular System
Factors responsible for SV are venous
return, ventricular distensibility, ventricular
contractility, systemic and pulmonary
resistance
Resting SV range from 60 to 100ml
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Effects on the Cardiovascular System
Cardiac Output (CO)
Amount of blood pumped by the heart per
minuteCO = SV x HR in one minute
Resting CO is about 4 to 8 L/min
Cardiac Reserve, ability to increase COwhen needed
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Effects on the Cardiovascular System
Blood Pressure (BP)
BP = CO x systemic vascular resistance
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Effects on the Cardiovascular System
Although peripheral resistance decreases
during exercise there is a significant
increase in the CO which lead to an
increase in mean arterial pressure due to
an increase in the systolic blood pressure
Systolic blood pressure increase can
range from 20 to 80 mm Hg
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Effects on the Cardiovascular System
Blood Flow
Increased blood flow to the skeletal and
cardiac muscles Increased in nutrient, oxygen, carbon
dioxide and other waste exchange
between the circulation and muscles
Increased skin temperature
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Effects on the Respiratory System
Pulmonary ventilation increases with
exercise
Increase in the depth and frequency ofrespiration
Increased respiratory reserve
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Effects on the Endocrine System
Increased hormone secretion
Increased metabolic rate
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Effects on the Immune System
Moderate exercise boost functions of
natural killer cells, T and B lymphocytes
and macrophages
May have a reverse effect
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Effects on the Muscular System
Hypertrophy
Increase contractile force
Increase in power, strength andendurance
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Long Term Adaptation to Exercise
Decrease in resting HR and Increased SV
Cardiac muscle hypertrophy
Increase respiratory reserve Increase muscle mass and cell size
Efficient metabolism
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Thank You
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