Cardiorespiratory Fitness & Exercise Programming

• Cardiorespiratory Fitness Assessments and Exercise Programming are for apparently healthy participants.

What is CRF?

• CRF refers to the ability of the circulatory and respiratory systems to supply oxygen to muscles during physical activity.
• VO2max represents CRF.
• VO2 is a measure of how well the body gets oxygen into the lungs (consumption), moves red blood cells to active skeletal muscle (transport), and extracts oxygen from red blood cells within active skeletal muscle to produce ATP (utilization).
• High CRF is associated with health benefits and a reduced risk of cardiovascular disease due to good transport and utilization systems.
• A dose-response relationship exists between exercise and reductions in chronic disease; improvements in any of the consumption, transport, or utilization systems are reflected in VO2.
• ACSM-EP's primary role is to develop and maintain CRF.

Anatomy & Physiology

• Heart Chambers:
  • Atria: upper chambers (left and right).
  • Ventricles: lower chambers (left and right).
  • Left Ventricle: pushes blood from heart through the vasculature.
• Vasculature:
  • Veins & venules: carry deoxygenated blood.
  • Arteries & arterioles: carry oxygenated blood.
  • Capillaries: responsible for gas & nutrient exchange.

Cardio Respiratory Response to Exercise

• During exercise, there is an oxygen deficit which, over time, comes up to the oxygen needed to perform activity
• Oxygen consumption eventually reaches a steady-state
• With the cessation of exercise, there is an oxygen debt, or EPOC
• Graded exercise programs use treadmills and other equipment to measure oxygen uptake

VO2max

• Determination of VO2max uses the Fick Equation:
  • VO2max = Cardiac Outputmax × (a-vO2△ diff max)
  • Cardiac Output = Heart Rate x Stroke Volume

Cardiovascular Responses to GXT (Graded Exercise Test)

• a-vO2△:
  • Represents the arteriovenous difference, which is the difference in O2 content of arterial and venous blood
  • At rest it will measure "low"
• Heart Rate:
  • Increases with workload until maximum heart rate (HRmax) is reached.
  • HRmax is estimated by 220 - age.
• Stroke Volume:
  • Increases with workload initially (up to 40-60% max)
  • There may be little change later in a GXT.
  • Increased stroke volume (SV) with training results in decreased resting heart rate.
• Pulmonary Ventilation (VE):
  • Linearly increases with workload through moderate intensity (up to ~50-80% max)
  • Has more rapid increases near max exertion.
  • Blood pressure increases

Assessments During Exercise

• Pre-Exercise needs to be assessed in the exercise position.
• During Exercise should be assessed at each exercise intensity.
• Post-Exercise should be assessed until stability.
• Rate Pressure Product:
  • Can overall myocardial demand be assessed during exercise?
  • This is derived from heart rate and systolic blood pressure.

Selecting Appropriate CRF Assessments

• Conduct assessments regularly on both healthy & clinical populations to monitor and evaluate cardiorespiratory fitness.

Cardiorespiratory Fitness Assessment Techniques

• Maximal oxygen uptake (VO2max):
  • Needs maximal exertion
  • Requires open-circuit spirometry during graded exercise test to volitional fatigue.
  • Major equipment needed includes a treadmill, cycle ergometer, arm ergometer, etc.
• Submaximal oxygen uptake:
  • Needs submaximal exertion
  • Requires the Astrand-Rhyming Cycle Ergometer Test or the YMCA Cycle Ergometer Test.
  • Major equipment needed includes a cycle ergometer
• Step tests:
  • Needs maximal or submaximal exertion
  • Requires the Queens College/McArdle Step Test or the Harvard Step Test.
  • Major equipment needed includes an aerobic step or specific height bench, and a metronome.
• Field tests:
  • Needs maximal or submaximal exertion
  • Requires the Rockport walk, 12-min walk/run test, or 1.5-mile run test.
  • Major equipment needed includes level walking/running surface.
• The selection of assessment should depend on:
  • Intensity, length, & expense needed to implement.
  • Type & number of personnel needed.
  • Equipment & facilities needed.
  • Physician supervision needed.
  • Safety concerns.
  • Required accuracy of results.
  • Appropriateness of mode of exercise.
  • Willingness of the participant to perform the test.
• Avoid the ‘one-size-fits-all’ approach.

Metabolic Calculations

• A MET = metabolic equivalent of task and is the rate at which an individual expends energy relative to their body weight.
• 1 MET = 3.5 ml of O2/kg of body weight/min.
• Think about the definition of a MET one more time...
  • A rate (min).
  • Expends energy (mL: 1 L of O2 = 5 kcal).
  • Relative to bw.
  • 1 = 3.5 ml of O2/kg of bw/min (aka the amount of energy you expend sitting at your desk right now; sedentary).

FITT-VP

• Provides the framework to establish an exercise prescription program
  • F = Frequency.
  • I = Intensity.
  • T = Time (or duration).
  • T = Type (or mode).
  • V = Volume (or amount).
  • P = Progression (or advancement).

Aerobic Exercise Recommendations using the FITT model

• Frequency:
  • At least 3 days/week.
  • For most adults, spreading the exercise sessions across 3–5 days/week may be the most conducive strategy to reach the recommended amounts of physical activity.
• Intensity:
  • Moderate (40%-59% HRR) and/or vigorous (60%-89% HRR) intensity recommended for most adults.
• Time:
  • Most adults should accumulate 30-60 min/day (≥150 min/week) of moderate-intensity exercise, 20–60 min/day (≥75 min/week) of vigorous-intensity exercise, or a combination of moderate- and vigorous-intensity exercise daily to attain the recommended targeted volumes of exercise.
• Type:
  • Aerobic exercise performed in a continuous or intermittent manner that involves major muscle groups recommended for most adults.

Principles of Training

• Progressive Overload: the need for exercise to be greater than accustomed to induce adaptation (i.e. more than yesterday).
• Reversibility: the opposite of the overload principle - 'use it or lose it'.
• Individual Differences: the same stimulus can produce very different responses within individuals - genetic factors.
• Specificity: specific exercise elicits specific adaptations, creating specific training effects.

Safe & Effective Exercises

• Walking.
• Jogging/running.
• Bicycling.
• Swimming.
• Aerobic machines.

Determining Exercise Intensity

• Options range from direct measurements to more subjective approaches
  • HRR Method
  • Peak HR Method
  • Peak VO2 Method
  • Peak MET Method
  • VO₂ Reserve Method
  • Talk Test Method
  • Perceived Exertion Method

Abnormal Reponses to Excercise

• Onset of angina or angina-like symptoms
• Drop in SBP of≥10 mm Hg with an increase in work rate, or if SBP decreases below the value obtained in the same position before testing
• Excessive rise in BP: SBP >250 mm Hg and/or DBP >115 mm Hg
• Shortness of breath, wheezing, leg cramps, or claudication
• Signs of poor perfusion: light-headedness, confusion, ataxia, pallor, cyanosis, nausea, or cold and clammy skin
• Failure of HR to increase with increased exercise intensity
• Noticeable change in heart rhythm by palpation or auscultation
• Participant requests to stop
• Physical or verbal manifestations of severe fatigue
• Failure of the testing equipment

Injury with CRF

• Intrinsic Risk Factors:
  • History of previous injury.
  • Inadequate fitness or conditioning.
  • Body composition.
  • Bony alignment abnormalities.
  • Strength or flexibility imbalances.
  • Joint or ligamentous laxity.
  • Predisposing musculoskeletal disease.
• Extrinsic Risk Factors:
  • Excessive load on the body.
  • Type of movement.
  • Speed of movement.
  • Number of repetitions.
  • Footwear.
  • Surface.
  • Training errors.
  • Excessive distances.
  • Fast progression.
  • High intensity.
  • Running on hills.
  • Poor technique.
  • Fatigue.
  • Adverse environmental conditions.
  • Air quality.
  • Darkness.
  • Heat or cold.
  • High humidity.
  • Altitude.
  • Wind.
  • Worn or faulty equipment.

Cardiorespiratory fitness (CRF) refers to the circulatory and respiratory systems' ability to supply oxygen to muscles during physical activity. High CRF is associated with health benefits and a reduced risk of cardiovascular disease. Improvements are reflected in VO2.