Principal Investigator Dr. S. Kowsalya Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore

Component – I

Role Name Affiliation

Principal Investigator Dr. S. Kowsalya Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore

Co-Principal Investigators Dr.Sheela Ramachandran Dr. Sylvia Subha Priya Dr.G .Bagyalakshmi Mrs.E.Indira

Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore

Paper Coordinator Dr.V. Saradha Ramadas Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore

Content Writer Dr. Jagmeet Madan

SNDT Women's

University,Mumbai-400049

Content Reviewer Dr.S. Premakumari Avinashilingam Institute for

Home Science and Higher Education for Women, Coimbatore

Language Editor Dr. Jagmeet Madan Avinashilingam Institute for

Home Science and Higher

Education for Women,

Coimbatore

Component-I (B) Description of Module Items Description of Module

Subject Name Food and Nutrition

Paper Name Nutrition Wellness and Fitness Module Name Cardio Respiratory Fitness

Module ID F13 NW09

Pre-requisites Fitness, improving performance, Body systems in exercise

Objectives

· To understand the effect of training on cardio respiratory fitness and cardio respiratory adaptations

· To understand methods of developing cardio respiratory fitness and tests to measure it.

Keywords

Quadrant - I

1. INTRODUCTION:

Higher physical activity is associated with cardio respiratory fitness which in turn results in better health.

Quantitative analysis in a number of studies indicated lesser risk of cardiovascular disease as a result of regular physical activity. These studies further indicated that if cardiovascular disease developed in people with regular physical activity, it developed at later stage of life.

Cardio respiratory fitness can predict cardiovascular disease more strongly than other traditional risk factors like hypertension, smoking, hyperlipidemia, obesity and type 2 diabetes mellitus. According to current guidelines, primary and secondary cardiovascular risk can be prevented by exercise. Also, CVD recurrence rate is reduced after exercise interventions.

The American Heart Association and American College of Sports Medicine recommend increasing physical activity or aerobic exercise training to increase levels of cardio respiratory fitness.

Response to exercise requires integration from pulmonary, respiratory, skeletal muscle and cardiovascular systems. Of all the systems, the most important is the cardiovascular system, particularly cardiac systolic and diastolic function.

2. OBJECTIVES:

· To understand the concept of cardio respiratory fitness and its effects on respiratory and cardiovascular systems

· To understand the effect of training on cardio respiratory fitness and cardio respiratory adaptations

· To understand methods of developing cardio respiratory fitness and tests to measure it.

3. CARDIO RESPIRATORY FITNESS

Cardio respiratory fitness is defined as the ability to perform repetitive, moderate to high intensity, large muscle movement for a prolonged period of time. During sustained and/or intense exercise, cardio respiratory fitness measures the capacity of the respiratory and cardiovascular system to provide muscles with oxygen.

Cardio respiratory fitness level measures the strength of the aerobic energy system. Cardiac performance, both physiological and morphological is altered positively by exercise. Cardio respiratory fitness is improved with moderate exercise.

Cardio respiratory fitness helps to identify the ability of the body to maintain a level of exertion for an extended period of time. It is determined by the body’s ability to take up, distribute, and use oxygen during physical activity. Cardio respiratory fitness depends on:

1. Oxygen Delivery System.

2. Oxygen Extraction System.

Oxygen delivery system is the efficiency of your heart, lungs and blood to deliver oxygen to the working muscle.

Oxygen extraction system is the efficiency of the working muscle to extract this delivered oxygen to generate energy for better functioning.

The cardiovascular and respiratory systems are majorly responsible for cardio respiratory fitness. The important functions of these systems are to provide the body with oxygen and nutrients. To respond to increased muscle activity associated with exercise, the cardiovascular system should be able to respond efficiently. The cardiovascular response to exercise is proportional to the oxygen demand and oxygen uptake.

4. VO2 MAX

Cardio respiratory fitness can be measured by the oxygen uptake (VO2). It is measured by the maximal oxygen uptake by a person during exercise. It is termed as VO2 max. The point at which a person's oxygen uptake is no longer able to increase is defined as maximal oxygen uptake (VO2 max). VO2 max of a person is partly determined genetically and partly can be increased through training until the point the genetically possible maximum is reached. It is the ability of the body to convert energy from food to energy molecules to be used by the body, ATP (adenosine triphosphate). ATP helps the body to continue exercise. As exercise intensity increases, VO2 also increases. The maximum volume of oxygen that the body is capable of consuming and converting to energy for working muscles is termed as VO2 max. VO2 max is considered to be the gold standard by which one can measure his or her cardio respiratory fitness level

Changes in oxygen uptake with increasing rates of work on the cycle ergo meter

Adapted From: Physical activity and health, Chapter 3. Physiological responses and long term adaptations to exercise, Figure 3-3, 67.

4.1 Measurement of VO2 max

VO2 is the difference between the amount of oxygen inspired by a person and the amount of oxygen expired. The test to determine VO2 max is available in laboratories as they have sophisticated laboratory equipments for measurement. During testing, a person progresses gradually from normal activity to maximum physical exertion. The test is usually done on a treadmill. At maximal activity i.e. when a person can no more exert a plateau phase will be reached. The highest measured VO2 at this plateau represents the VO2 max of the individual.

Normal values for VO2 max

The table below displays standard VO2max classification ranges for both men and women.

Adapted from:

V. H. Heyward, Advanced Fitness Assessment and Exercise Prescription, Fifth Edition, 2006, Champaign, IL: Human Kinetics.

Original Source:

The Cooper Institute for Aerobics Research, The Physical Fitness Specialist Manual. Dallas, TX. 2005.

4.2 Factors influencing VO2 max:

1. Genetics: The upper limit for VO2 max is determined by the genetic makeup

2. Age: The VO2 max varies according to age. It peaks at around 18 years and remains the same till about 25 years of age. Beyond 25 years the VO2 max decreases. The graph represents changes of VO2 max with age

Changes in VO2 max with increasing age from 6 to 18 years of age in boys and girls

Adapted From: Physical activity and health, Chapter 3. Physiological responses and long term adaptations to exercise, Figure 3-4, 75.

3. Fitness level: By following the ASCM training guidelines, a person can improve VO2 max from 5% to 30%.

4. Form of exercise: VO2 max varies with specific form of exercise, since oxygen is ultimately consumed in the muscles during exercise. For example, there is usually more total muscle mass active during running than during swimming, and so VO2max will generally be greater when measured during a running test than it would be if measured during a swimming test. Treadmill running type tests typically return the highest VO2max scores.

5. Body mass and body composition: Body tissues consume oxygen. A person with more body mass is likely to consume more oxygen for its tissues. A more muscular person is thus expected to have a higher VO2 max compared to a person who is leaner.

6. Gender: VO2 max differs according to the gender of the individual. Generally men are seen to have higher VO2 max levels as compared to women. These differences are biologically predetermined and are largely due to size differences of the contracting muscles.

5. Benefits of Cardio respiratory Fitness

Efficient functioning of the heart depends on cardio respiratory fitness level. If the cardio respiratory fitness is good, the heart will be able to sustain high intensity of physical activity. The cardio respiratory fitness level varies for different level of physical activity. The cardio respiratory fitness level demanded will be much higher for a soccer player than that of a construction worker, body builder, or computer technician.

However, the cardio respiratory fitness affects the cardiovascular system of all.

Cardio respiratory fitness benefits the heart and lungs. When he heart and the lungs are functioning efficiently, the muscles can pull more oxygenated blood out of the blood stream and also the blood will be able to carry more oxygen. The heart pumps more blood with each heart beat and thus the body recovers faster from exercise. The long term benefits of cardio respiratory fitness are plenty. It not only improves cardiovascular health at the present but also helps to reduce further risk of heart disease, prevent hypertension in the near future, improve blood lipid levels, and improve overall health and everyday normal functioning.

Many positive changes, benefits and training adaptations have been associated with cardio respiratory fitness.

5.1 Reduction in coronary heart disease (CHD) risk factors

• Reduced resting blood pressure

• Increased HDL cholesterol

• Decreased triglycerides

• Reduced body fat and intra-abdominal fat

• Reduced insulin needs, and improved glucose tolerance

• Reduced blood platelet adhesiveness and aggregation 5.2 Improvement in cardiovascular and respiratory function

• Increased VO2 max (maximal oxygen uptake)

• Increased stroke volume

• Stronger heart

• Decreased heart rate (HR) and blood pressure at sub maximal work loads

• Increased capillary density in skeletal muscle

• Increased anaerobic threshold

• Increased stamina, endurance, energy

5.3. Other benefits

• Decreased anxiety and depression

• Enhanced feelings of well-being

• Enhanced performance of work and sport activities

• Enhanced function and independent living in older persons

• Improved sleep

• Improved immune function

• Increased quality of life

• Decreased morbidity and mortality

Regular exercise further reduces the overall risk of cardiovascular disease by 50 percent.

6. A. EFFECT OF TRAINING ON CARDIO RESPIRATORY FITNESS

The response of the cardiovascular system, which is composed of the heart, blood vessels and blood, is predictable to the increasing demands of exercises. The skeletal muscle’s demand for oxygen during work increases the cardiovascular response to exercise. The oxygen uptake also increases linearly with exercise.

6.A .1 EFFECT ON CARDIAC OUTPUT

Cardiac output plays an important role in meeting the oxygen demands for work. The cardiac output increases as the rate of work increases. This increase is almost in a linear manner. This increase is because the oxygen demands need to be met. However, it increases only to the point it reaches its maximal capacity (Q max).

Change in Cardiac output with increasing rate of work

6.A.2 EFFECT ON STROKE VOLUME

Stroke volume increase only up to 40-60%, after which it reaches a plateau.

6.A.3 EFFECT ON BLOOD FLOW

The blood flow in a person changes when a person starts to exercise from a resting state. During the resting state, 20% of the cardiac output is received by the skin and skeletal muscles. However, as one begins

to exercise more amount of blood is sent to the active skeletal muscles. Also, during exercise, the body temperature increases, hence more blood is sent to the skin to maintain thermoregulation. During this process, 80% of the cardiac output is sent to the active skeletal muscles and skin which are maximal rates of work.

When exercise is carried out in a more hot and humid environment, more cardiac output will be sent to the skin to counter the correspondent increase in body temperature.

6.A.4 EFFECT ON BLOOD PRESSURE

Blood pressure tends to increase with exercise, particularly systolic blood pressure as diastolic blood pressure remains at near resting levels. Increased rate of work causes a linear increase in the systolic blood pressure. The value reaches between 200 and 240 millimetres of mercury in normotensive patients. The mean arterial pressure is equal to cardiac output time’s total peripheral resistance. Therefore, the observed increase in mean arterial pressure results from an increase in cardiac output that outweighs a concomitant decrease in total peripheral resistance. This response of the body of the increase in mean arterial pressure is a normal and desired response. It is a result of a resetting of the arterial baroreflex to a higher pressure. If such a resetting was not present, the body would experience severe arterial hypotension during intense activity. In patients who have hypertension, the response of intense activity on systolic pressure is higher, hence their diastolic blood pressure also increases as the rate of work increases. Thus, the mean arterial pressure in such patients is much higher.

6.A.5 EFFECT ON RESPIRATORY RESPONSE

The challenges of exercise cause the respiratory system to respond. The most immediate response is increase in pulmonary ventilation. Increase in CO2 production, hydrogen ions (H+) , and body and blood temperatures at higher rates of work, further increase pulmonary ventilation. The respiratory rate of the body also increases at higher intensities of work. The pulmonary ventilation rate in normal untrained individuals can vary from 10 litres per minute at rest to more than 100 litre per minute at maximum work levels. The pulmonary ventilation rates in highly trained male athletes can reach more than 200 litres per minute at maximum work level.

6.B EFFECT OF RESISTANCE TRAINING

The effects of the cardiovascular and respiratory system on resistance training are almost similar as that during endurance training. The only important difference is that the blood pressure is exaggerated during resistance training. This may be because resistance training usually involves muscle mass which requires

administration of considerable force. Thus, the smaller arteries are compressed as result of this increased force. This results in substantial increase in total peripheral resistance.

7. ADAPTATIONS TO EXERCISE TRAINING

A number of adaptations take place in the cardiovascular and respiratory systems as a result of exercise.

The magnitude of these adaptations largely depends on the person’s initial fitness level; on mode, intensity, duration, and frequency of exercise; and on the length of training.

7.1 CARDIAC OUTPUT ADAPTATIONS

Following an endurance training program, cardiac output, essentially remains the same. However at maximum rates of work, the cardiac output is increased substantially by 30 percent or more.

7.2 STROKE VOLUME ADAPTATIONS

After training, at rest, the stroke volume is increased. This may be contributed to the fact that post endurance training the plasma volume increases. As a result of the increased plasma volume, the volume of blood available to be return to the right heart, and subsequently to the left ventricle is increased. Because of this increased volume of blood and increased return of blood, the diastolic volume also increases. Ventricular dilatation is a short term adaptive response. Hypertrophy of the cardiac muscle fibres is a long term adaptive response. This hypertrophy increases the muscle mass of the ventricles, permitting greater force to be exerted with each beat of the heart.

7.3 RESPIRATORY ADAPTATIONS

During endurance training, the tidal volume and respiratory rate increase. At maximal rates of work, the pulmonary diffusion is also increased due to increase in pulmonary blood flow, particularly to the upper regions of the lung. All of these changes lead to an increase in the maximal rate of pulmonary ventilation.

8. DEVELOPING CARDIO RESPIRATORY FITNESS: AEROBIC EXERCISE PROGRAM

An exercise program should be developed according to the muscular strength as well as endurance. Before building a program, a few points need to be kept in mind

1. Genetics: the genetic ability of each individual varies. A program should be designed keeping in mind the genetic abilities of an individual

2. The starting point: If the activity of a person is low, he/she would start and progress faster compared to a person who is already exercising

3. Commitment: Gaining and maintain high levels of strength takes a steady commitment.

Warm-up, conditioning stimulus and cool down is the three basic components of any exercise training program.

Warm up and cool down- Warm up and cooling down are important components. Warming up before beginning to exercise increases the temperature of the body slightly above resting level. It also helps to decrease the chance of injury. With a warm up, the heart gets time to adapt to increased intensity. Also, the body pumps and redirects blood to the active muscles at the time of a warm up. A warm session should be of a low intensity with whole body movements. 5-10 minutes of a warm session should be undertaken before any exercise program. Stretching, walking cab be a part of warm up sessions.

Cooling down after exercise is as equally important as a warm up. It helps to get the body back to the normal resting state. The heart rate slowly returns to normal. This prevents a large drop in blood pressure, dizziness and other potential cardiovascular complications. It also helps to maintain blood flow. 5-10 minutes of cooling down should be carried out after intense physical activity. The intensity of exercise should be decreased gradually during cooling down.

30 minutes or more of moderate-intensity physical activity on most days of the week (intermittent activities have same health benefits as continuous activities)

8.1 THE AEROBIC EXERCISE PROGRAM SHOULD BE DESIGNED USING THE FITT THEORY.

Frequency, Intensity, Time (duration), and Type of activity.

I) Frequency: ACSM recommends aerobic activity to be performed for atleast 3-5 days a week. This ensures complete adaptation to the training program. Training in excess ( more than 5 days a week), may lead to injuries and training for fewer than 3 days leads to inadequate adaptation and may therefore not have any positive impact on the overall fitness level.

II) Intensity: The most important aspect of an exercise training program is determining the intensity of exercise. Different methods have been employed for estimating and deciding the intensity of training. These include:

1) Target Heart Zone 2) MET

3) Rate of perceived Exertion (RPE) 4) Talk Test

1) Target Heart Zone: The easiest method to estimate the intensity of an aerobic fitness program is determining one’s heart rate. An individual need not exercise at maximum heart rate (MHR) to develop cardio respiratory fitness, adaptations occur best at a lower heart rate and this also reduces the risk of injuries.

ACSM recommends training at 65-90% of maximum heart rate. This depends on the fitness level and capacity of an individual and is termed as ‘Target Heart Zone’. This is the heart rate at which cardio respiratory benefits are at its peak.

Target Heart Zone (THZ) is calculated as follows:

1) Calculate MHR: 220-Age

2) To calculate THZ: Multiply MHR by 65% and/or 90% (This depends on the basal fitness level and health of an individual, for example, for very unfit individuals MHR is multiplied by 55%)

For example, for a 23 year old:

MHR= 220-23= 197

65% training intensity= 0.65*197=128 BPM 90% training intensity=0.90*197=177 BPM

Thus, for achieving cardio respiratory fitness, exercise should be performed between 128-177 beats per minute.

Instead of Target Heart Zone, Heart Rate Reserve may also be used to determine exercise intensity. This is calculated as the difference between maximum heart rate and resting heart rate (MHR-RHR)

The intensity of the training program should be increased gradually. Sedentary individuals should begin with a lower target heart rate for atleast 4-6 weeks and progressively increase the same. If the intensity of the exercise is kept at a lower rate, the frequency or duration may be increased (within limits) in order to obtain maximum benefits. For individuals with a lower initial fitness level, an intensity of 55-64% of MHR may be sufficient to start, for average individuals 70-85% of MHR may be suitable.

2) MET: MET represents the body’s resting metabolic rate. MET describes fitness in terms of the capacity to increase basal metabolism. MET is the oxygen consumption at rest. It is represented as volume of oxygen consumed per kilogram per minute.

1 MET = 3.5ml/kg/min

When MET is expressed in terms of metabolic rate, exercise intensities of less than 3–4 METs are considered low. Moderate intensity exercises increase metabolic rate by 6-8 METs and metabolic rate is increased by more than 10 METs during vigorous activity.

However, MET is only an approximation of exercise intensity and is affected by skin, weight, body fat and environment.

3) Ratings of Perceived Exertion: It is an accurate way to check on exercise intensity and is also easier and more convenient than Target heart Zone or MET. It is estimated by assigning a numerical value to subjective perception to exercise exertion. This scale was designed by Gunnar Borg and is also known as the Borg scale.

The Borg scale is given below:

6 No exertion at all 7 Extremely light 8

9 Very light 10

11 Light 12

13 Somewhat hard 14

15 Hard (heavy) 16

19 Extremely hard 20 Maximal Exertion

4) Talk test: During cardio respiratory endurance exercise, the breathing rate increases. However, it shouldn’t increase to an extent at which an individual is unable to talk. The talk test is an effective estimate of intensity for many types of activities.

III) Time (Duration) of training: ACSM recommend 20-60 minutes of aerobic exercise to develop cardio respiratory fitness. This can either be done together or in intermittent sessions. The intensity of exercise will determine its duration:

a) Low to moderate ( such as walking) – 45-60 minutes b) High intensity- 20 minutes

c) Extremely vigorous activity- 5 to 10 minutes

IV) Type of activity: The following aerobic activities can be performed to develop cardio respiratory fitness:

a) Brisk walking b) Jogging c) Cycling d) Swimming e) Aerobic dancing

These are only a few amongst many.

Any activity that involves rhythmic movements of large muscles for an extended time period helps in improving cardiovascular endurance

.

The FIIT principle for training

8.2 TRAINING PROGRESSION:

3 stages are involved in progression:

1. Initial conditioning stage 2. Improvement conditioning stage 3. Maintenance conditioning stage

Stage Week Exercise

Frequency

Exercise Intensity

(% of HR)

Exercise duration

Initial Conditioning

1 3 40-50 15-20

2 3 40-50 20-25

3 3-4 50-60 20-25

4 3-4 50-60 25-30

Improvement Stage

5-7 3-4 60-70 30-35

8-10 3-4 60-70 30-35

11-13 3-4 65-75 30-35

14-16 4-5 65-75 35-40

17-20 4-5 70-85 35-40

21-24 4-5 70-85 35-45

Maintaince stage

24+ 3-5 70-85 30-40

Adapted From: American College of Sports Medicine.2006. ACSM’s Guidelines for Exercise Testing &

prescription.

9. TESTS TO ESTIMATE CARDIO RESPIRATORY FITNESS:

1) Gold Standarad- VO2 max:

2) Treadmill test: it should be electronically driven. And have a wide range of speeds from 1.6 km to 12.8km. Elevation should also be electronically contolled, with options from no elevation to 20% elevation.

3) Cycle ergometer: This is an alternative for treadmill test. It is less expensive and portable. Work intensity can be adjusted by variations in resistance and cycling rate. Work rate can be calculated in watts or kilopond-meters per min⁻¹ (kpm/min). physiological responses differ between treadmill test and cycle ergometer. Maximun oxygen uptake is 5-20% lower on cycle ergometer than treadmill. Two types of stationary cycles are used: mechanically braked and electronically braked.

4) Shuttle run and 5) distance/timed run 10. SUMMARY:

· The cardiorespiratory system consists of heart, blood vessels and respiratory system

· It involves oxygen delivery and oxygen extraction

· VO2 max is used as a gold standard to determine cardiorespiratory fitness

· A number of factors have an effect on VO2 max

· Cardio respiratory fitness involves many benefits including reduced risk of cardiac diseases and metabolic syndrome

· It also builds up the respiratory system

· Both endurance and resistance training have a positive impact on cardio respiratory fitness

· An exercise program for building cardio respiratory fitness should be planned using FIIT principle

· The exercise program should be tailor made and progressed gradually

· Various tests are available for estimating cardio respiratory fitness

Journal References:

· Carl J. Lavie et al, Exercise and the Cardiovascular System, American Heart Association, Circulation Research, 2015

· Leonard A. Kaminsky et al, The Importance of Cardiorespiratory Fitness in the United States: The Need for a National Registry, A Policy Statement From the American Heart Association,2013

· ACSM's Guidelines for Exercise Testing and Prescription, American College of Sports Medicine, 2006

· Cardiorespiratory Fitness Fitness, ACE Personal Trainer Manual, Third Edition

· Lance dalleck, , Angela dalleck ,The ACSM exercise intensity guidelines for cardiorespiratory fitness: why the misuse?, Journal of Exercise Physiologyonline, 2008

· Ileana L. Pina et al , Guidelines for Clinical Exercise Testing Laboratories, A Statement for Healthcare Professionals From the Committee on Exercise and Cardiac Rehabilitation, American Heart Association, American Heart Association.

· Jonathan Myersa et al, Physical Activity and Cardiorespiratory Fitness as Major Markers of Cardiovascular Risk: Their Independent an d Interwoven Importance to Health Status, Progression in Cardiovascular Diseases, 2015-08-03

Textbook Reference:

· Cardiorespiratory Programming, Personal Fitness Training: Theory and Practice, Chapter 6

· Physical activity and Health, Physiologic responses and long-term adaptations to exercise, Chapter 3

· Health-Related Fitness Measures for Youth: Cardiorespiratory Endurance. Available from:

http://www.ncbi.nlm.nih.gov/books/NBK241309/

· Cardiorespiratory endurance, Fit and Well online learning centre

· Katch VL, Katch FI, McArdle WD, Exercise Physiology: Energy, Nutrition, & Human Performance,2007

· Plowman SA, Smith DL, Exercise Physiology: for Health, Fitness, and Performance, 2nd Edition, 2003

· Health and Wellness for Life, By Human Kinetic