Eval chap13

Chapter 13: Exercise Prescription for Aerobic Fitness

1. Outline of Key Topics

  • Dose-response concept in exercise

  • Physical activity guidelines

  • Exercise intensity

  • Supervised and unsupervised programs

  • Environmental issues

2. Dose-Response Concept in Exercise

  • Exercise Potency

    • Ability to bring about desired results.

    • Slope: Degree of effect from increased exercise dose.

    • Maximal Effect:

      • Vigorous activity improves risk factors and VO2max; moderate activity impacts VO2max less.

  • Variability

    • Individual responses to exercise vary significantly.

  • Side Effects

    • Injuries and interactions with medications affecting physiological variables (e.g., glucose, blood pressure).

3. Exercise Dose (FITT-VP)

  • FITT-VP Principle

    • Frequency of exercise

    • Intensity of exercise

    • Time (duration) of exercise

    • Type of exercise

    • Volume of exercise: calculated as frequency × intensity × time

    • Progression: gradual increase in difficulty or duration.

4. Responses to Exercise

  • Short- and Long-Term Responses

    • Acute Responses: Immediate effects after one or few exercise bouts.

    • Rapid Responses: Early improvements plateau over time.

    • Linear Responses: Continuous gains over time.

    • Delayed Responses: Improvements occur after several weeks of consistent training.

5. Physical Activity Guidelines for Americans (2nd Edition)

  • Recommended for improved health:

    • 150 to 300 minutes of moderate-intensity PA per week or 75 to 150 minutes of vigorous-intensity PA per week.

    • Additional health benefits from >300 minutes of moderate-intensity activity.

    • Engage in resistance training 2 days per week.

    • Minimize sitting and increase daily movement.

6. Guidelines for Increasing Cardiorespiratory Fitness (CRF)

  • Promote screening and regular participation.

  • Focus on progression in a structured program.

  • Increase duration by about 10% per week before intensity.

  • Use interval training to transition to continuous vigorous activity.

  • Include warm-ups and cool-downs; dynamic stretches during warm-up and static during cool-down.

  • Target a 10% improvement in CRF over 3 months.

7. Formulating an Exercise Prescription (Dose)

  • Overall exercise dose recommendation: 500 to 1,000 MET-minutes per week or 1,000 kcal per week.

8. Exercise Frequency and Intensity

  • Frequency Recommendations:

    • Moderate intensity: ≥5 days per week

    • Vigorous intensity: ≥3 days per week.

    • For sedentary individuals, aim for less than 4 days of vigorous intensity to reduce dropout and injury risks.

  • Intensity Goals:

    • Expressed in %VO2max, %HRR, %HRmax, or RPE.

    • Sedentary individuals should start near 40-60% HRR, progressively moving towards 60-80% HRR.

9. Selecting Exercise Type and Time

  • Type of Activity

    • Options include walking, running, cycling, and recreational sports.

  • Time Considerations

    • Balance between intensity and duration.

    • Total work (kcal burned) is essential for CRF gains.

10. Environmental Issues

  • Heat and Humidity

    • Factors influencing heat injury risk: fitness level, hydration, temperature, humidity, wind.

  • Cold Exposure

    • Hypothermia risks: environmental elements that affect thermoregulation.

  • Air Pollution

    • Major pollutants limit oxygen transport and increase airway resistance.

  • Altitude Effects

    • At high altitudes (e.g., 7,300 feet), VO2max decreases and HR tends to increase at submaximal workloads.

11. Case Studies

  • Case Study 1 (Roberto):

    • Analyze risk factors, BMI, GXT response, and recommendations.

  • Case Study 2 (Tia):

    • Assess risk factors, BMI, GXT response, and program suggestions.

Effects of Regular Aerobic Exercise Program:

  1. VO2 Max: Regular aerobic exercise leads to improvements in VO2 max, indicating enhanced cardiovascular fitness.

  2. Resting Heart Rate: Here, a regular aerobic program typically results in a lower resting heart rate, suggesting improved heart efficiency.

  3. Max Heart Rate: Max heart rate generally remains stable with training, although trained individuals may perform better at high intensity.

  4. Heart Rate During Submax Workload: Over time, heart rate responses to submaximal workloads decrease, indicating improved efficiency.

  5. Percent Body Fat: Aerobic exercise can help reduce percent body fat through caloric expenditure and improved metabolic rate.

Calculating Intensity using ACSM Guidelines:

  1. % VO2 Max Reserve:

    • Formula: Intensity = ((%VO2Max/100) x VO2Max) + (Resting VO2)

    • Convert ml/kg/min to METs: 1 MET = 3.5 ml/kg/min.

  2. % Heart Rate Reserve (Karvonen Formula):

    • Formula: Target HR = ((Max HR - Resting HR) x % Intensity) + Resting HR.

  3. RPE (Rate of Perceived Exertion): Utilizes a scale (typically 6-20) for subjective assessment of exercise intensity. Exercise intensity is typically 12-16 RPE for moderate to vigorous intensity.

ACSM Recommendations for Prescribing Cardio Exercise (FITT-VP):

  • Frequency: Moderate intensity (≥5 days/week), Vigorous intensity (≥3 days/week)

  • Intensity: % VO2R/HRR, RPE 12-16

  • Time: 150-300 minutes moderate or 75-150 minutes vigorous intensity per week

  • Type: Variety of aerobic activities such as walking, running, cycling

  • Volume: 500 to 1000 MET-minutes/week

  • Progression: Gradually increase frequency, intensity, and time.

Ranges for Intensity (%VO2R/HRR):

  • Sedentary Individuals: Start at 40-60% HRR, moving towards 60-80% HRR.

  • Moderate Intensity: 40-60% VO2R, RPE ~12-14.

  • Vigorous Intensity: 60-80% VO2R, RPE 14-16.

Calculating Exercise Volume and MET-Minutes:

  • Volume: Volume = Frequency x Duration x Intensity.

  • MET-Minutes: MET-minutes = MET value of exercise x duration in minutes.

Counting Risk Factors:

Be aware of established risk factors including age, family history, smoking status, sedentary lifestyle, obesity, hypertension, dyslipidemia, and diabetes. Knowing these aids in assessing overall cardiovascular risk.