Cardiorespiratory Fitness

Fundamentals:

1) Aerobic type PA → changes in cardiorespiratory system

2) Cardiorespiratory system changes both structurally and functionally

3) Functional + Structural changes → improved aerobic metabolism + aerobic PA

  • improves in daily living and unusual activities of daily living

  • improved physical health → reduced morbidities

  • reduced all causes of mortality (higher aerobic power → better survival rate)

  • reduced risk of chronic disease (e.g cancer)

*MET → measurement of max. O2 consumption

Increase in CR fitness is measured in METs → reduces risk of premature death (linear relation)

*CR fitness > 7METS → significant protection for some cancers

4) sufficient volume of aerobic PA exercise bout/per week → results in CR fitness increase

5) Aerobic exercises → continuous rhythmic movements of major muscle groups

6) CR fitness is measured by VO2 max/MET max (max. oxygen consumption)

*you have to do enough to stimulate an effect

*sub-maximal tests can be conducted to understand a persons CR fitness through calculations

CR system → Lungs, heart, arteries, capillaries, red blood cells, mitochondria

  • These all work together to deliver oxygen to the mitochondria to make ATP aerobically

Adaptations: increased CR health → more efficient to get O2 to body

  • lungs are more efficient at diffusing O2 into blood

  • heart wall thicker + ventricles get bigger

  • each heart beat becomes more efficient

  • overall volume in arteries increase

  • grow new capillaries in skeletal muscles → increase O2 delivery to muscle fibres

  • red blood cell count goes up → more O2 to deliver → more O2 pressure → more O2 forced into muscles

  • more mitochondria to accept O2 → mitochondria translocate to wall of muscle fibre

  • increased enzyme content for increasing ATP made with O2 goes up in mitochondria

Tests to measure CR fitness → VO2max/METs:

1) lab or field test → standardized environment vs. modified

2) CR tests will be direct or predicted → device vs. equation

3) Cr tests will be maximal or sub-maximal → capacity vs not reach capacity

  • Cooper 12 min run → strong correlation to VO2 max.

  • Leger’s shuttle run (Beep Test) → the person must pivot at the pylon and change direction quickly (no bus turn)

  • mCAFT protocol → CSEP recommended, stairs 20.3cm, follow audio, overload done by increasing stepping rate

  • modifies mCAFT → stop when a certain HR is achieved, target is 85% of age predicted max HR, 3 min stages

  • aerobic fitness score → age, weight, O2 cost from table

CR fitness Exercise Prescription:

  • dictations the appropriate duration of the workout as well as the pattern

Train in the aerobic zone → more than resting VO2 but less than VO2 max

*watch out for over prescription

Determination of intensity → measured by VO2 (O2 consumption) or Heart Rate (easier)

  • aerobic zone is divided into sub zones → different zone have different metabolisms with different acute and chronic effect on the body.

  • Zone 1 - very light-light effort → 100% aerobic metabolism

  • Zone 2 - moderate effort → mostly aerobic metabolism, mix of fat and carbohydrates

  • Zone 3 - vigorous/max. effort → some aerobic but ATP mostly supplied by anaerobic

*aerobic metabolism lingers and does not go away in each zone

*vast majority of metabolism is aerobic

anaerobic threshold and aerobic threshold is determined by the 3 zones, graded tests from rest to max. will measure blood lactate or ventilation and VO2/O2

two tables for CR intensity → healthy adult aerobic intensity prescription + table 5 ACSM

table 5 → describes 3 zones, specific aerobic intensity prescription, primarily HR is used

**athletes use a different table → shows blood lactate, appropriate % of max ranges, intensity range

3 Types of Aerobic prescription:

  • physiological - heart rate or METS (need device to measure)

  • Perceptual/feelings - rating of perceived exertion → talk test

How to prescribe intensity for aerobic exercise: (HR, HRR%, RPE, METs)

HR:

  • actual max. HR → max. exercise test

  • if unable to find true max. heart rate → use prediction equation

  • equations: Inbar - best, Robergs & Landwehr → good, Standard → not good

  • decide intensity category → select method of prescribing heart rates → determine HR range (77%-95%) *use HRmax equation → provide HR range for client to meet

Target HR = HR max - HR rest x prescribed intensity (using %HRR) + HR rest

RPE - rating of perceived exertion:

  • can be used as a validity prescription of intensity as it is tied with the intensity zones

  • 0-10 RPE scale or 6-20 Borg scale

  • RPE + HR → combined aerobic exercise intensity prescrption

Talk test:

  • concept - you can only talk when you exhale

  • Low intensity → very comfortable to talk (low breathing intensity)

  • Moderate → can still talk normally

  • Vigorous → can’t talk due to high breathing rate

Steps?

  • ACSM recommends 7000 steps/day

  • increasing steps by 2000 steps/days reduces the risk of cardiovascular disease

  • 100 steps/min → moderate intensity

METS as a concept:

  • allows the energy cost of any activity to be quantified

  • ** 1METS=3.5ml O2/kg/min

  • METS x Kg = calories burned for the exercise

  • every 0.05 EE → +3 MET

  • more METS → moves a person closer to their VO2max as they require more oxygen

FITT and CR Fitness Prescriptions:

  • each component must fit together

  • each component must be addressed to a complete prescription (activity, time, days per week, RPE)

  • Appropriate rate warm-up, cooldown

  • duration - intensity relationship

  • variety balance

  • aerobic exercises that are enjoyable

3 phases to aerobic conditioning programs:

Initial conditioning:

  • Type A activities (e.g walking, cycling)

  • develop the habit of exercise with minimal discomfort and soreness → engaging activities

Improvement stage:

  • goal is to gradually increase the overall exercise stimulus to allow for significant improvements in CR fitness

  • understand the limit to prevent overtraining

  • the challenge is to increase training at a rate that continues to stimulate progress without overtraining

  • duration is variable but is typically 6 months (4~8)

  • Type B activities (e.g jogging, rowing)

Maintenance stage:

  • goal is to maintain all that was attained in the improvement stage

  • reduced frequency and exploring new capabilities

  • keystone days can be used to switch some Type B with Type C activities (e.g swim)

  • Type D (e.g pass time activities) can be added on the occasional keystone day

  • There is potential to induce more adaptation → transferability; varied stimulus can unintentionally improve CR

  • Keystone → the most important workouts that got a person to their goal