Lecture 4 Flashcards
physical activity
any bodily movement produced by the contraction of skeletal muscles that results in an increase in caloric requirements over resting expenditure
Exercise
(subclass of physical activity) planned structured and repetitive bodily movement done to improve or maintain one or more components of physical fitness
Physical fitness
a set of attributes or characteristics that people have or achieve that relates to the ability to perform physical activity and activities of daily living
Components of Physical fitness (3)
- Have a strong relationship to good health
- characterized by an ability to perform daily activities with vigor
- demonstrate traits and capacities associated with low risk of premature development of hypokinetic diseases (associated with physical inactivity)
Health-related components of physical activity (4)
- Cardiorespiratory endurance or fitness (CRF)
- Body composition
- Muscular strength and endurance
- Flexibility
VO2 Max is a ___ criterion for cardiorespiratory endurance capacity
standard
VO2 max (physiologic definition)
maximal capacity to transport and utilize oxygen
- reflects the capacity for aerobic energy transfer*
- reflects the level of function and integration of physiologic systems involving uptake, delivery and utilization of oxygen*
Cardiorespiratory endurance or cardiorespiratory fitness
ability to perform large muscle, dynamic, mod-high intensity exercise for prolonged periods
Cardiorespiratory fitness is a ____ issue
health-related
a low level of cardiorespiratory fitness is associated with markedly increased risk of:
premature mortality from all causes (esp. cardiovascular disease)
Increases in CRF (cardiovascular fitness) is associated with:
- reduction in death from all causes &
- higher levels of habitual physical activity → health benefits
Purposes of Health-Related Fitness Testing
- Obtain data needed for writing exercise prescriptions
- Evaluation of progress in an exercise program
- Motivation via provision of realistic exercise goals
- Education on current fitness status
- Health-related risk stratification
Purposes of clinical exercise testing
- Diagnostic testing (assessing for disease)
- Disease severity and prognosis
- Clinical management
- Functional testing
Exercise electrocardiography (ECG) 3 purposes
- Assess presence and severity of coronary artery disease (diagnosis)
- predict the likelihood of future cardiac events (prognosis)
- Analysis of exercise-induced arrhythmias
ECGs are beyond the scope of this course; however, know that ST segment changes are common findings with myocardial ischemia → ST elevation or depression can be seen
Radionuclide exercise testing (nuclear cardiology)
Radionuclides (infused IV) are rapidly taken up by cardiac muscle and the pattern and rate of uptake and clearance provides information on:
- Myocardial perfusion
- Ventricular function
Myocardial perfusion
for detection of coronary artery stenosis and muscle ischemia
Ventricular function
size and shape of ventricular chambers during cardiac cycle; cardiac volumes; regional wall motion
Clinically, radionuclide imaging during exercise is used for:
diagnosis of coronary artery disease in symptomatic individuals
Prognosis of a future event in patients with stable coronary artery disease
Post-MI assessment of myocardial ischemia, viability, ventricular function
3 ways to measure/estimate VO2 max
- directly measure VO2 max using pulmonary gas exchange measurements
- Determining VO2 max directly using gas exchange measurements
- Estimate VO2 max from maximal exercise intensity
- Estimate VO2 max from submax testing protocol
Primary criterion for reaching VO2 Max
plateau in oxygen uptake with a further increase in workload
plateau may not be observed if patient cannot handle an additional increase in workload (a particular problem in sedentary persons). It is estimated that 50% of adults and children undergoing ex. testing will fail to demonstrate a definable plateau in VO2 before fatiguing. Issue is even more likely if patient has CV our pulm disease.
VO2 peak is a term used when
a discernable plateau in VO2 max is not achieved with CPX
widely accepted method of tracking an exerciser’s subjective rating of effort
RPE (RPE can be influenced by mood, environmental conditions, exercise modes and age)
Despite these limitations, for a given individual, RPE helps to track impeding exhaustion during maximal exercise test
Factors that affect VO2 Max
- Mode of Exercise
- Heredity (genetics)
- Gender
- Body size and composition
- Obesity
- Aging
- Activity level (training)
Factors that affect VO2 Max
Mode of exercise: variation among modes often reflect differences in the quantity of _____ activated
muscle mass
Factors that affect VO2 Max
Sex: VO2 max in untrained women is lower than ___
untrained men
Factors that affect VO2 Max
Body size and composition: VO2max is proportional to amount of:
contracting muscle
why arm ergometry results in lower VO2 max than leg ergometry
Factors that affect VO2 Max
Obesity: Actual VO2max values are slightly higher than expected because of _____
training effect of moving excess weight
Factors that affect VO2 Max
Age:
VO2max rises during childhood and reaches peak at ___
Gender differences manifest at ___
peak at ~20
gender differences manifest at puberty
Factors that affect VO2 Max
Activity level:
- VO2 max is higher in ____ persons than sedentary persons
- VO2 will ___ if habitually active person becomes sedentary
- Higher in habitualy active persons
- VO2 will decreaase if habitually active person becomes sedentary
