cardiovascular fitness the ability of the body to utilize oxygen efficiently
TRANSCRIPT
Cardiovascular Fitness
• The ability of the body to utilize oxygen efficiently.
Cardiovascular Fitness
• In designing the exercise prescription, keep in mind that some people engage in aerobic exercise to improve their health status or reduce their disease risk, while others are primarily interested in enhancing their physical fitness and performance levels.
Cardiovascular Fitness
• Given that the quantity of exercise needed to promote health is less than that needed to develop and maintain higher levels of physical fitness, you must adjust your exercise prescription according to your client’s primary goal.
Cardiovascular Fitness
• Improvement is CV fitness is measured by assessing changes in VO2MAX
Cardiovascular Fitness
• Increases in VO2MAX may range from 5 to 30%.
Cardiovascular Fitness
• Individuals with low initial levels of fitness, cardiac patients, and those exhibiting large losses of body weight will demonstrate the greatest percent increase in VO2MAX.
Cardiovascular Fitness
• Similarly, more modest increases may be expected from healthy individuals with high initial levels of fitness and those who exhibit little change in body weight.
Improved Health
• When the primary goal for the exercise prescription is improved health, the following guidelines are recommended:
Improved Health
• Mode:
• Select endurance-type physical activities, including formal aerobic exercise training, house and yard work, and physically active, recreational pursuits.
Improved Health
• Intensity
• Prescribe at least moderate intensity physical activities (> 40 - 45% of VO2R or HRR, and 55-64% of HRMAX).
Improved Health
• Frequency
• Schedule physical activity for most, preferably all days of the week.
Improved Health
• Duration
• Accumulate at least 30 minutes of activity each day.
• Duration varies depending on type of activity.
Optimal Fitness
• When the primary goal for the exercise prescription is to attain optimal fitness, the following guidelines should be followed.
Mode
• The greatest improvement in VO2MAX occurs when exercise involves the use of large muscle groups over prolonged periods and is rhythmic and aerobic in nature.
Mode
• A wide range of activities provides for individual variability relative to skill and enjoyment, factors which influence compliance to the exercise program and thus desired outcomes.
Mode
• It may be desirable to engage in several different activities to reduce repetitive orthopedic stresses and involve a greater number of muscle groups.
Mode
• Because improvement in muscular endurance is largely specific to the muscles involved in exercise, it is important to consider unique vocational or recreational objectives of the exercise program when selecting activities.
Mode
• Finally, it is important to consider other barriers that might decrease the likelihood of compliance with, or adherence to, the exercise program (travel, cost, spousal or parent involvement, etc.).
Intensity
• Intensity and duration of exercise determine the total caloric expenditure during a training session, and are integrally related.
Intensity
• That is, similar increases in CV endurance may be achieved by a low intensity, long duration session as well as a higher intensity, shorter duration session.
Intensity
• The risk of orthopedic injury may be increased with the latter; however, programs emphasizing low-to moderate-intensity exercise with a longer training duration are recommended for most individuals.
Intensity
• Part of the art of exercise prescription is being able to select an exercise intensity that is adequate to stress the cardiovascular system without overtaxing it.
Intensity
• As a general rule, the more fit the individual, the higher the exercise intensity needs to be to produce further improvement in CV fitness.
Intensity
• ACSM recommends that the intensity of exercise be prescribed as 65 to 90% of maximum heart rate, or 50 to 85% of VO2R or heart rate reserve.
Intensity
• VO2R refers to maximum oxygen uptake reserve.
• It is calculated by subtracting resting VO2 from VO2MAX
Intensity
• However, individuals with a very low initial level of fitness respond to a low exercise intensity, for example 40 to 49% of VO2R
Intensity
• Several important factors to consider prior to determining the level of exercise intensity include:
Intensity
• Individual’s level of fitness.
• Presence of medications that may influence heart rate
Intensity
• Risk of cardiovascular or orthopedic injury.
• Individual preferences for exercise.
• Individual program objectives.
Intensity
Factors that can impact intensity include:
• Altitude
• Humidity
• Temperature
• Terrain
Intensity
• Exercise surface
• Equipment
Intensity
• Several methods may be used to determine exercise intensity.
HR Methods
• Using HR as a guide to exercise intensity is useful, given the relatively linear relationship between HR and VO2
HR Methods
• When prescribing exercise intensity based on HR, consideration must be given to potential influences.
HR Methods
• Given exercise test data, there are several approaches to determining an exercise HR range for prescriptive purposes:
HR Methods
• Using a straight percentage of HRmax
• Using the HR reserve method.
• Plotting HR vs VO2 or exercise intensity during the exercise test.
HR Methods
• Go over each method:
• HRmax
• Karvonen
• Plotting
HR Methods
• It is important to note that the HR response to graded exercise is somewhat dependent on the mode of exercise testing.
HR Methods
• For example, compared to treadmill testing, exercising on an electronic step ergometer elicits higher HRs, and stationary cycling typically results in somewhat lower HRs at the same relative exercise intensities.
HR Methods
• When using the plotting method to obtain HRs for an exercise prescription, be sure to match the exercise testing and training modes by selecting a testing mode that elicits HR responses that are similar to those obtained for the training mode.
HR Methods
• Using HR exclusively to develop intensity recommendations for your clients’ exercise prescriptions may lead to large errors in estimating relative exercise intensities for some individuals.
HR Methods
• Medication, emotional states, and environmental factors such as temperature, humidity, and air pollution can affect your clients’ exercise training heart rates.
METS
• Prescribing by METs is most logically applicable to the apparently healthy and those with high VO2MAX values
METS
• It is less applicable for individuals with cardiac or pulmonary disease, or for individuals with low functional capacities.
METS
• First, assess the client’s functional aerobic capacity using a graded exercise test.
METS
• Use this value to determine the minimum, average, and maximum conditioning intensities.
METS
• For example, if the VO2MAX is 35 ml . kg-1 .
min-1 , the functional capacity is 10 METs.– 1 MET = 3.5 ml . kg-1 . min-1
METS
• The minimum training intensity is 50% of this value or 5 METs; the average intensity is 60 to 70% or 6 to 7 METs; the maximum exercise intensity is 85% or 8.5 METs.
METS
• Thus, the exercise prescription for an apparently healthy, active individual should include activities that produce an average intensity of 6 to 7 METs.
METS
• The exercise intensities (METs) for walking, jogging, running, cycling, and bench stepping are directly related to the speed of movement, resistance, or mass lifted.
METS
• Use the ACSM equations to calculate the speed or work rates corresponding to a specific MET intensity.
RPE
• The RPE scales are valid and reliable tools for assessing the level of physical exertion during aerobic exercise.
RPE
• You can use the intensities (METs) corresponding to ratings of 12 (somewhat hard) and 16 (hard) to set the minimum and maximum training intensities for the exercise prescription.
RPE
• Compared with the %HRR method, RPEs between 11 and 16 closely approximate 50 and 85% HRR, respectively.
RPE
• With practice an individual can learn to associate RPE with a specific target exercise heart rate, especially at higher exercise intensities.
RPE
• Thus, the RPE can be used instead of HR, or in combination with HR, to monitor training intensity and to adjust the exercise prescription for conditioning effects.
RPE
• One advantage of RPE as a method of monitoring exercise intensity is that your clients do not need to stop exercising in order to check their heart rates.
Duration
• The time constraints imposed on the individual influence both the frequency and duration of exercise sessions.
Duration
• Increases in exercise duration should be instituted as the individual adapts to training without evidence of undue fatigue or injury.
Duration
• Duration may be determined by the total time expended exercising or by the caloric cost of the activity.
Duration
• The ACSM recommends 20-60 minutes of continuous physical activity to develop optimal fitness.
Duration
• It is now known that this period of time can be split into smaller segments and result in similar benefits.
Duration
• A minimum of 10 minute bouts accumulated throughout the day are recommended if an intermittent approach is selected.
Duration
• To achieve health benefits, minimum caloric thresholds of 150 to 300 kcals per exercise session or 800 to 900 kcals per week are recommended.
Duration
• Throughout the improvement stage, the goal is to increase your client’s caloric expenditure from 800 to 2000 kcals per week by gradually increasing the frequency, intensity, and duration of the exercise.
Duration
• You can estimate the caloric cost of exercise (kcal per min) if you know exercise intensity (METs) and the relationship between METs and caloric cost:
• 1 MET = 1 kcal per kg per hr
Frequency
• Frequency is interrelated with both intensity and duration of exercise and therefore depends on those two variables.
Frequency
• However, functional capacity is of great importance.
Frequency
• Patients with functional capacities of < 3 METS benefit from multiple short daily exercise sessions; one to two sessions/day are most appropriate for three to five MET capacities; and 3 to 5 sessions/week are recommended for individuals with functional capacities > 5 METS.
Frequency
• Clearly the number of exercise sessions per week will vary given caloric goals, participant preferences, and limitations imposed by the participant’s lifestyle.
Caloric Thresholds for Adaptation
• The interaction of intensity, duration, and frequency determines caloric expenditure.
Caloric Thresholds for Adaptation
• ACSM recommends minimal thresholds of 300 kcal per exercise session performed 3 days per week, or 200 kcal per session done 4 days per week.
Caloric Thresholds for Adaptation
• It would appear that a reasonable approach in prescribed exercise programs is to target a weekly exercise caloric expenditure of approximately 1000 kcal.
Caloric Thresholds for Adaptation
• To achieve optimal physical activity levels the goal is to bring the weekly expenditure closer to 2000 kcal as health and fitness permits.
Caloric Thresholds for Adaptation
• One useful method to approximate the caloric cost of exercise is by using the following equation based on the MET level of the activity:– METS x 3.5 x body wt in kg / 200 = kcal/min
Progression
• The recommended rate of progression in an exercise conditioning program depends on functional capacity, medical and health status, age, and individual activity preferences.
Progression
• When selecting aerobic exercise modes for your client’s exercise prescription, you should consider how easily the exercise intensity can be graded and adjusted in order to overload the CV system throughout the improvement stage.
Progression
• For apparently healthy adults, the endurance aspect of the exercise prescription has three stages.
Initial Conditioning Stage
• The initial stage should include light muscular endurance exercises and low level aerobic activities (40 to 49% of HRR or VO2R), exercises which are compatible with minimal muscle soreness, discomfort, and injury.
Initial Conditioning Stage
• Exercise adherence may decrease if the program is too aggressively initiated.
Initial Conditioning Stage
• This stage usually lasts 4 to 6 weeks, but the length depends on the adaptation of the individual to the exercise program.
Initial Conditioning Stage
• The duration of the exercise session during the initial stage should begin with approximately 12 to 15 minutes and progress to 20 minutes.
Initial Conditioning Stage
• It is recommended that individuals who are starting a conditioning program exercise three times per week on non-consecutive days.
Improvement Stage
• In this stage, the participant is progressed at a more rapid rate.
Improvement Stage
• This stage typically lasts 4 to 5 months, during which intensity is progressively increased within the upper half of the target range of 50 to 85% VO2MAX
Improvement Stage
• Duration is increased consistently every 2 to 3 weeks until participants are able to exercise for 20 to 30 minutes continuously.
Improvement Stage
• The frequency and magnitude of the increments are dictated by the rate at which the participant adapts to the conditioning program.
Improvement Stage
• Deconditioned individuals should be permitted more time for adaptation at each stage of conditioning.
Improvement Stage
• Age should also be taken into consideration when progressions are recommended, as experience suggests that adaptation to conditioning may take longer in older individuals.
Maintenance Stage
• The maintenance stage of the exercise program usually begins after the first six months of training.
Maintenance Stage
• During this stage the participant may no longer be interested in further increasing the conditioning stimulus.
Maintenance Stage
• Further improvement may be minimal, but continuing the same workout routine enables individuals to maintain their fitness levels.
Maintenance Stage
• At this point, the goals of the program should be reviewed and new goals set.
Maintenance Stage
• To maintain fitness, a specific exercise program should be designed that will be similar in energy cost to the conditioning program and satisfy the needs and interests of the participant over an extended period.
Maintenance Stage
• It is important to include exercises that the individual finds enjoyable.