Chapter 13 NUTRITION AND PHYSICAL ACTIVITY. Exercise, Health and Fitness Fitness is defined as the ability to perform routine physical activity without

Chapter 13NUTRITION AND PHYSICAL ACTIVITY

Exercise, Health and Fitness Fitness is defined as the ability to perform routine

physical activity without undue fatigue. The overload principle assumes that the body will

adapt to the stresses placed on it. Aerobic exercise includes endurance exercises such as

jogging, swimming or cycling, or any exercise that increases heart rate and requires oxygen in metabolism.

The cardiorespiratory system includes the circulatory and respiratory systems, delivering oxygen and nutrients to the cells.

Copyright 2012, John Wiley & Sons Canada, Ltd.

Exercise, Health and Fitness Fifty five percent of adults are physically unfit. The Canadian Health Measure Survey 2007

and 2009 show a decline in fitness. Because of the impact of physical activity on

health, the Canadian government has launched initiatives to increase activity: Canada’s Physical Activity Guide ParticipACTION (relaunched)


The Toll of Physical Inactivity


Exercise, Health and Fitness


Exercise, the Heart and the Muscles Regular aerobic exercise strengthens the heart muscle, increases

stroke volume and decreases the resting heart rate. The resting heart rate can be measured by counting the number of

pulses per minute while at rest. Aerobic capacity is the body’s maximum ability to generate ATP by

aerobic metabolism during exercise. Aerobic capacity is also called VO2 max.

Stress or overload during exercise causes muscles to adapt by increasing in size and strength. This is called hypertrophy.

When muscles are not used, they atrophy, becoming smaller and weaker.

Exercise builds and maintains muscles. People who are fit have a greater proportion of lean body tissue than those who are not fit.


Health Benefits of Exercise In addition to increased flexibility and the

ability to easily perform daily activities, benefits of regular exercise include:

Weight management Cardiovascular health Diabetes prevention or management Bone and joint health Possible reduction of cancer risk Psychological health


Exercise Recommendations


Target Heart Rates During Aerobic Exercise


Components of a Good Exercise Regimen


Fueling Exercise Aerobic metabolism is metabolism in the presence of

oxygen. Glucose, fatty acids and amino acids are completely broken down to form CO2 and H20 and to produce ATP.

Anaerobic metabolism is metabolism in the absence of oxygen. Each molecule of glucose produces two molecules of ATP. Glucose is metabolized in this way when oxygen cannot be supplied quickly enough to the tissues to support aerobic metabolism.

Anaerobic metabolism is also called anaerobic glycolysis.


Fueling Exercise by the Minute


The Process of Anaerobic Metabolism


The Effect of Exercise Intensity


Nutrient Needs for Physical Activity


Relationship of Exercise to Intake The source of dietary energy can be as important as

the amount of energy in an athlete’s diet. Vitamins and minerals requiring special attention from

athletes: B vitamins Antioxidant vitamins, such as vitamins C and E Iron Calcium

The general proportion of energy for athletes and healthy individuals should be:

45-65% total energy from carbohydrates 20-35% from fat 10-35% from protein


Fluid Needs for Physical Activity During exercise, water is needed to eliminate heat, to transport

oxygen and nutrients to the muscles and to remove waste products such as lactic acid from the muscles.

The ability to dissipate heat depends on hydration levels. At rest in a temperate climate, an adult loses about 4½ cups of

water per day through evaporation from the skin and lungs. Even with regular consumption, it may not be possible to

consume sufficient fluid to remain properly hydrated. Failure to compensate for fluid losses can result in dehydration. If heat cannot be lost from the body, body temperature rises and

exercise performance as well as health can be jeopardized.


Fluid Needs for Physical Activity Dehydration occurs when water loss is great enough for

blood volume to decrease. Dehydration reduces the body’s ability to deliver oxygen

and nutrients to muscles.


Heat-Related Illnesses


Recommended Fluid Intake


Hyponatremia


What Are You Getting From That Sports Bar?


Evaluating the Benefits and Risks of Ergogenic Supplements


Claims, Benefits and Risks of Popular Ergogenic Aids


Claims, Benefits and Risks of Popular Ergogenic Aids (continued)









Caffeine


Impact of Diet versus Supplements


Copyright

Copyright © 2012 John Wiley & Sons Canada, Ltd.

All rights reserved. Reproduction or translation of this work beyond that permitted by Access Copyright (The Canadian Copyright Licensing Agency) is unlawful. Requests for further information should be addressed to the Permissions Department, John Wiley & Sons Canada, Ltd. The purchaser may make back-up copies for his or her own use only and not for distribution or resale. The author and the publisher assume no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information contained herein.

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Chapter 13 NUTRITION AND PHYSICAL ACTIVITY. Exercise, Health and Fitness Fitness is defined as the ability to perform routine physical activity without