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Chapter 14 – Fitness: Physical Activity, Nutrients, and Body Adaptations
Learning Objectives
After completing Chapter 14, the student will be able to:
1. List the benefits of regular physical activity.
2. Explain the components of fitness and conditioning.
3. Describe the energy systems of physical activity, including ATP and CP.
8. Describe the uses of protein during exercise and determine the protein needs of the athlete.
9. Discuss the roles of vitamin E and iron in the athlete.
10. Explain sports anemia and the iron requirements for the athlete.
11. Discuss fluid needs of the athlete and the symptoms and consequences of inadequate intake.
12. Describe the hydration schedule for physical activity and the need for electrolyte replacement.
Assignments and Other Instructional Materials
The following ready-to–use assignments are available in this chapter of the instructor’s manual:
• New! Case study
• Worksheet 14-1: Cardiorespiratory Endurance Calculation
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Other instructional materials in this chapter of the instructor’s manual include:
• Answer key for How To (p. 469) activity
• Classroom activities
• Worksheet answer keys (as appropriate)
Lecture Presentation Outline
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“Of special interest to…” symbol key: = Hot Topic = Personal Health
= Health Care Professionals = Science Majors
Key to instructor resource annotations (shown to the right of or below outline topics):
PL = Available on Power Lecture DVD-ROM (ISBN 0538797592): V = video
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Worksheets 14-1 and 14-4 contributed by Daryle Wane.
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Introductory/whole chapter resources: PL figure JPEGs; Test Bank; IM WS 14-2, CA 14-1
I. Fitness IM WS 14–4, CI 14.2, 14.3
Fitness involves physical activity or exercise. The components of fitness are cardiorespiratory endurance,
flexibility, muscle strength, and muscle endurance. All of these characteristics describe a healthy body.
Today’s world encourages sedentary lifestyles that foster the development of several chronic diseases.
A. Benefits of Fitness
1. There are many benefits:
a. Restful sleep.
b. Nutritional health.
c. Optimal body composition.
2. The 2008 Physical Activity Guidelines for Americans state that people should avoid inactivity and stay
physically active to promote health.
a. Aerobic physical activity is necessary to obtain substantial health benefits.
b. The duration of activity recommended is dependent on whether the activity is a moderate-
intensity activity or a vigorous-intensity activity.
B. Developing Fitness 11e TRA 26; 12e TRA 20; IM WS 14–3, CA 14-2
1. Guidelines for conditioning that is achieved through training. IM CI 14.1
a. Cardiorespiratory Endurance
1. Frequency – 5-7 days per week.
b. Strength
1. Frequency – 2 or more nonconsecutive days per week.
c. Flexibility
1. Frequency – 2-3 days per week.
2. Intensity – enough to develop and maintain a full range of motion.
3. Duration – 4 repetitions of 10-30 seconds per muscle group.
2. The Overload Principle – to slightly increase comfortable capacity in each area. This is also called the
progressive overload principle.
3. The Body’s Response to Physical Activity
a. Hypertrophy is muscle gain in size and strength, the result of repeated work.
b. Atrophy is muscle loss in size and strength, the result of lack of activity.
c. Other Tips
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5. Challenge yourself, but not every time you exercise.
4. Cautions on Starting a Fitness Program
a. Healthy people can start with a moderate exercise program without seeking medical advise first.
b. People with risk factors may need medical advice.
C. Cardiorespiratory Endurance 10e TRA 149; IM WS 14-1
1. Cardiorespiratory conditioning is measured by maximum oxygen uptake (VO2max).
a. Increases cardiac output and oxygen delivery.
2. Muscle Conditioning
a. Muscles use oxygen efficiently.
b. Muscles can burn fat longer.
3. A Balanced Fitness Program
a. Individualized.
D. Resistance Training is also called weight training.
1. Increases muscle strength, power, and endurance.
2. Prevents and manages cardiovascular disease.
II. Energy Systems and Fuels to Support Activity
The mixture of fuels used during physical activity depends on diet, intensity and duration of the activity, and
A. The Energy Systems of Physical Activity—ATP and CP
1. ATP is adenosine triphosphate – a high-energy compound that delivers energy instantaneously.
2. CP is creatine phosphate – a high-energy compound in the muscles, used anaerobically.
3. The Energy-Yielding Nutrients
a. Nutrients work together while one may predominate.
b. Depends on diet, intensity and duration of the activity, and training.
1. Extremely intense activity
a. 8-10 seconds.
2. Very highly intense activity
a. 20 seconds to 3 minutes.
3. Highly intense activity
a. 3-20 minutes.
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d. Activity examples – cycling, swimming, and running.
4. Moderately intense activity
a. More than 20 minutes.
d. Activity example – hiking.
B. Glucose Use during Physical Activity
1. Diet Affects Glycogen Storage and Use
2. Intensity of Activity Affects Glycogen Use
a. Moderate activities use glycogen slowly.
b. Intense activities use glycogen quickly.
3. Lactate
a. Low-intensity activities can clear lactate from the blood.
4. Duration of Activity Affects Glycogen Use
5. Glucose Depletion
a. “Hitting the wall” – exhaustion of glucose stores.
b. Maximizing glucose supply
1. High-carbohydrate diet – 8 g/kg body weight or 70% of total energy intake.
2. Glucose during activities if activity lasts longer than 1 hour (sports drinks or diluted fruit
6. Glucose during Activity
a. Activities lasting longer than 1 hour.
b. Should consume 30-60 grams of carbohydrate per hour.
7. Glucose after Activity
8. Training Affects Glycogen Use
a. Muscles that repeatedly deplete glycogen through hard work will store greater amounts of
C. Fat Use during Physical Activity
1. Duration of Activity Affects Fat Use
2. Intensity of Activity Affects Fat Use
a. As intensity increases, fat makes less of a contribution to the fuel mix.
b. Oxygen must be abundant to break down fat.
3. Training Affects Fat Use
a. The better trained the muscles, the more fat is used.
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D. Protein Use during Physical Activity—and between Times
1. Protein Used in Muscle Building
a. Synthesis of protein is suppressed during activity.
2. Protein Used as Fuel
3. Diet Affects Protein Use during Activity
4. Intensity and Duration of Activity Affect Protein Use during Activity
a. If glycogen stores get depleted, then more reliance on protein.
b. Anaerobic strength training demands more protein to build muscles but not large amounts.
5. Training Affects Protein Use – the more trained the less protein used for energy.
6. Protein Recommendations for Active People
a. Athletes in training need more protein than sedentary people.
III. Vitamins and Minerals to Support Activity
A. Supplements
1. Do not enhance performance.
B. Nutrients of Concern
1. Vitamin E supplements have shown inconsistent results with the vitamin’s effects on free radicals.
2. Iron deficiency
3. Iron-Deficiency Anemia
4. Sports Anemia
5. Iron Recommendations for Athletes
a. Blood tests should guide the decision.
b. Depends on the individual.
IV. Fluids and Electrolytes to Support Activity PL V “Hot-Weather Exercise Tips”; IM CA 14-3
A. Temperature Regulation
1. Introduction
a. Muscle heat is 15-20 times greater when active than at rest.
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c. 1 liter of sweat dissipates 600 kcalories of heat.
2. Hyperthermia – an above-normal body temperature.
a. Body heat builds up.
b. Triggers maximum sweating without sweat evaporation.
c. Symptoms of heat stroke – a dangerous accumulation of body heat with accompanying loss of
body fluid.
1. Headache.
3. Hypothermia – a below-normal body temperature. Symptoms begin with shivering and euphoria and
progress to weakness, disorientation, and apathy.
4. Fluid Replacement via Hydration
a. Full hydration is imperative for athletes.
1. Two to three hours before activity – 2-3 cups.
2. 15 minutes before activity – 1-2 cups.
3. Every 15 minutes during activity – ½-1 cup.
4. After activity – 2 cups for every pound of body weight lost.
5. Electrolyte Losses and Replacement
a. Greater in the untrained.
6. Hyponatremia
a. Decreased concentration of sodium in the blood.
b. Causes
1. Excessive sweat.
2. Overhydration.
c. Symptoms
1. Severe headache.
d. Prevention
1. Replace sodium during prolonged events.
2. Do not restrict salt in the diet in the days leading up to events.
B. Sports Drinks
1. Provide fluids to replace losses.
2. Provide glucose polymers that maintain hydration and blood sugar.
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A. Choosing a Diet to Support Fitness 10e TRA 150
1. Water
a. Thirst mechanisms are not as reliable.
b. Must be replenished.
2. Nutrient Density – consume nutrient-dense foods that are high in carbohydrate, moderate in fat, and
adequate in protein.
3. Carbohydrate
a. 60%-70% total energy intake.
4. Protein
a. Strength athletes: for males 84-119 g/day, females 66-94 g/day.
b. Endurance athletes: for males 84-98 g/day, females 66-77 g/day.
5. A Performance Diet Example 10e TRA 151
B. Meals Before and After Competition
1. Pregame Meals
a. Fluids.
2. Postgame Meals
a. High-carbohydrate meals.
b. Liquids often preferred.
A. Ergogenic Aids
1. Problems with distinguishing valid claims versus bogus claims.
2. Marketing techniques are used to generate sales.
3. Substances promoted as ergogenic aids
a. Arginine is a nonessential amino acid.
b. Boron is a nonessential mineral.
B. Dietary Supplements
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1. Carnitine
2. Chromium Picolinate
a. Essential mineral in carbohydrate and lipid metabolism.
b. Supplementation has no effect on strength, lean body mass, or body fat.
3. Complete Nutrition Supplements
4. Creatine
5. Conjugated Linoleic Acid (CLA)
6. Caffeine
a. Caffeine can enhance performance by stimulating fatty acid release.
b. Adverse effects include stomach upset, nervousness, irritability, headaches, and diarrhea.
c. Use in moderation.
d. Use as an addition to other fluids, not as replacement.
C. Hormonal Supplements
1. Anabolic Steroids
a. Illegal.
2. DHEA (dehydroepiandrosterone) and Androstenedione
3. Human Growth Hormone (hGH)
a. Used to build lean tissue and increase height if still growing.
Case Study
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Theresa is a 17-year-old high school student who gained 20 pounds her junior year of high school when she quit the
girls’ soccer team and joined the debate team. She is 5 feet 2 inches tall and weighs 154 pounds. She has been
monitoring her food intake for 2 weeks and reports eating about 1600 kcalories a day. Although her weight is stable
at this calorie level, she would like to lose weight. She notes that she has not been consistent with her exercise,
although she enjoys getting out by herself or with her family to walk or jog or go to the beach. She comes to you for
encouragement and a fitness program that is reasonable for her lifestyle.
1. Explain to Theresa the benefit of well-trained muscles on body composition and weight control.
2. Explain to Theresa the basic components of a balanced fitness program and the necessity of each component.
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5. Based on a 1600-kcalorie diet, calculate how many kcalories from carbohydrates, fat, and protein are provided
in a diet that derives 60 percent calories from carbohydrate, 25 percent from fat, and 15 percent from protein.
Calculate the daily grams of each of these nutrients for Theresa to consume. (Remember that 1 gram of
carbohydrate or protein yields 4 kcalories and 1 gram of fat yields 9 kcalories.)
6. Assuming Theresa will begin her exercise program this week, what advice for fluid intake do you recommend
(including type and amount)?
Answer Key:
1. Muscles that use oxygen efficiently burn fat longer; exercise that builds muscles burns more calories and can
help her lose weight without having to severely decrease her calorie intake. The more muscle she has, the more
energy she will burn.
Suggested Classroom Activities
Fitness and athletics are receiving much attention these days and as a result students are increasingly interested in
issues of nutrition to support physical activity. This chapter will assist students by providing information about how
to exercise and how to nourish themselves for optimal performance.
Classroom Activity 14-2: Physical Activity Diary
Key concept: Evaluation of physical activity Class size: Any
Instructions: Instruct students to keep an activity log or diary in which they can record physical activities they
participate in daily. Have them keep the record for seven days, and ask them to bring the record to class. Divide
students into groups and have them evaluate their activity patterns. (You could use Worksheet 14-3 in conjunction
with this activity.)
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Classroom Activity 14-4: Fitness Quackery Evaluation
Key concept: Evaluation of fitness information from the media Class size: Medium to small
Classroom Activity 14-5: Fitness Facility Evaluation
Key concept: Evaluation of fitness facilities Class size: Any
Instructions: Instruct students to visit a local fitness facility and investigate the dietary advice they offer as part of
the service. Do they sell nutrient supplements? What qualifications or training in nutrition do the fitness instructors
have?
How To “Try It” Activities Answer Key
How to Maximize Glycogen Stores: Carbohydrate Loading
4-7 days before the event: 350 carbohydrate g per day; 1-3 days before the event: 700 g carbohydrate per day
Critical Thinking Questions
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These questions will also be posted to the book’s website so that students can complete them online and e-mail their
answers to you.
1. As discussed in this chapter, there are many benefits of physical activity. For clients participating in a weight-
loss program, what are some of the benefits of physical activity that a client might gain greater benefit from,
and in what areas might the dietitian want to be more cautious and provide more frequent assessments?
Answer: A client undergoing weight loss can often benefit even more from the advantages of physical activity.
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Any client undergoing changes in diet and lifestyle, including exercise, should be monitored closely. One would
want to check the client’s cardiovascular and respiratory systems on a regular basis. Also include blood sugar
levels for type 2 diabetes and watch mood and behavior for signs of anxiety, depression, and eating disorders.
Clients undergoing weight loss can change their biochemical parameters (blood lipids, blood sugar, and beyond)
quickly. Depending on the patient’s medical history, severity of problem, progress, etc., patients/clients must be
monitored for relapse or development of a problem that is not anticipated. Weight loss is a great goal; however,
some clients do have underlying issues that can make them highly vulnerable to compromise with many
changes. It is always best to be alert.
2. Discuss the body’s use of high-energy compounds and energy nutrients during physical activity. In other words,
differentiate between an athlete’s energy needs for short-distance and sprint events vs. endurance events.
Answer: The body retains many sources of energy for exercise.
The most immediate source of energy is two compounds called ATP and CP: these are adenosine triphosphate
and creatine phosphate. These energy sources are used by the muscles and are quickly available to them for
A high-carbohydrate diet provides more energy for the athlete over the short term.
Fatty acids: Epinephrine signals the fat cells to break down fat for use in physical activity. Once glycogen is
utilized or when performance is at 60% or less than VO2 max, the body uses fatty acid for energy. These types
of athletic events are primarily aerobic events rather than quick, short bursts of intense exercise, and are
characterized as the endurance types of sports. Fatty acids are a rich source of energy, depending on the
individual, allowing for greater than 70,000 kcal of energy. Clearly fat is a great energy source for distance
events, but fatty acids are unavailable for short events that are anaerobic.
3. Manufacturers of sports drinks select top athletes to speak in commercials for this multi–billion dollar business.
In your opinion, are the benefits of sports drinks worth their cost? There is no right or wrong answer!
Answer: Table 14-7 provides a start for the students to start thinking about this question. In the field of sports
nutrition, athletes will take anything that they hear will benefit their “game.” The RD that is not prepared to
substantiate their point of view will not have credibility in the athletic world. It is always best to work with the
4. As your chapter points out, physical activity provides many great benefits for an individual’s cardiovascular and
respiratory systems and emotional well being, and helps to maintain their bone health and flexibility. Yet,
exercises done improperly can be harmful to an individual, and there are also many products on the market that
are promoted to improve a person’s game—products that may truly have no value. Imagine yourself as a
famous sports dietitian with a broad clientele. Discuss areas of concern that you would need to address with the
following clients.
These are two vary different athletes that are motivated and working hard. What are your assessment concerns
for each, what are your recommendations, and why?
A 45-year-old male “weekend warrior” has decided to return to his favorite college team sport of running to get
back into shape and lose some weight. At present, he is 20 pounds overweight and has not been to his physician
for about 1.5 years, but at that time he states he was in perfect health. He has decided to go on a popular high–
protein diet to help hasten his weight loss and support tissue repair from the running. His eating plan includes
protein bars, protein shakes, and protein water drinks. He is also taking chromium, zinc, vitamins C and E, and
tryptophan supplements. He is presently running 3 miles a day, 4 days a week, and 10 miles a day, 2 days a
week. His goal is to be able to do a marathon in six months.
Your second client is a world–class female figure skater aged 13 years. At present, she is 5’ 2” tall and weighs
95 pounds. She has not started her menstrual cycle but appears to be in Tanner stage 5 or full sexual
development. Her coach does not want her to gain any further weight for her height; however, if she does get
taller, then he may be amenable. Her diet is approximately 60% protein, 35% carbohydrate, and 5% fat. She
eats lean meats but tries to stay with the vegetarian proteins, complex carbohydrates, and monounsaturated fatty
acids. She is very motivated about her diet and her mother is constantly watching her as well as her coach. She
does eat salads and fruits and of course exercises or works out approximately 10 hours a day, if not more at
times. Along with diet, this athlete consumes unknown supplements and ergogenic aids to support her athletic
training. At her young age, she has won several world championships and is considered the next Olympic gold
medal champion. The Olympics are two years away and she is highly motivated to be there and win.
Answer: For the instructor, the point of the exercise is to demonstrate to the student some of the issues that can
arise with athletic clients, taking athletic issues from two very different perspectives.
First client: With a “weekend warrior” the RD must be careful to assess all physiological and medical
parameters as well as his diet to protect him from injury and more importantly long-term damage from his new
regime. First, it is great that he has decided to get active and undertake a more healthful diet; however, when a
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It is best to encourage this athlete to consume a multivitamin rather than all the different supplements, at
random. Given that these supplements will not enhance performance, this individual can benefit more from a
multivitamin supplement, given the diet, rather than taking supplements that have no proven benefit. It is also a
better balance for the nutrients overall in the body. To help influence this client toward this direction, the RD
might discuss the benefits of gaining vitamins and minerals through the foods one eats rather than in
supplement form because of the variety of factors that influence their uptake and use in the body. However, if
the client insists on taking these supplements, no harm will come from their use and the RD can thus remain
flexible with clients. This flexibility increases trust between the client and nutrition professional.
Second client: This world-class skater is under constant medical and training care. Therefore, we know that she
has been assessed medically. In general, most of these athletes have an athletic trainer that provides some
nutrition information. At times there may be an RD. Her diet is too high in protein, so she needs to increase the
fat intake to 10% and increase the carbohydrate intake to 65%. At her age, she is especially in need of the fat for
steroid production as well as cellular membranes, etc. Given that she consumes more of a vegetarian diet, I
would also suggest that she take a multivitamin with iron to ensure that she is receiving all her necessary
vitamins and minerals.
Overall, it would be important to work with the skater and her mother (perhaps separately and then together) on
some cycle menus and snack ideas. Given the age and energy expenditure of this skater, her energy
requirements are very high. Her estimated energy expenditure is 4549.22 on a daily basis. To consume this
many calories can be difficult and with everyone watching the skater, it is important for the mother, coach, and
skater to understand her needs and to work with each other to plan healthful food choices that can be available
Most of all, while this particular skater appears to enjoy what she is doing, this sport can become very stressful
and many skaters become disillusioned early in their careers. Remind her to have fun with her skating and with
what she eats. A good diet includes a variety of foods so that boredom does not set in while still nourishing
one’s body to perform.
5. Differentiate between moderate-intensity and vigorous-intensity aerobic activity. How does “the overload
principle” impact the outcome of the physical activity that an individual participates in?
Answer: Aerobic physical activity is basically cardiovascular fitness training. It is the type of activity that
allows an individual to move all body parts and work the cardiovascular and respiratory systems as well as the
muscular and skeletal systems for a positive influence on health status.
IM Worksheet Answer Key
Worksheet 14-1: Cardiorespiratory Endurance Calculation
Worksheet 14-2: Chapter 14 Crossword Puzzle
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Worksheet 14-3: Physical Activity Self-Evaluation – Answers will vary.
Worksheet 14-4: Fitness Review (Internet Exercise)
Canadian Information
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14.1 Physical Activity Guide to Healthy Active Living
Note: Effective September 2004, the Public Health Agency of Canada (PHAC) was established and the Healthy
Living Unit within PHAC assumed lead responsibility from Health Canada for delivering the federal government’s
role in physical activity. Resources published prior to this date and referenced to Health Canada should now be
assumed to be resources of the PHAC.
14.2 Physical Activity in Canadian Adults
The Canadian Fitness and Lifestyle Research Institute reports on physical activity trends in Canada. Using 2004
Canadian Community Health Survey data, 51% of adults are classified as inactive,
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defined as an average daily
14.3 Nutrition and Physical Activity on the Net—Canadian
The Healthy Living Unit of PHAC promotes active living and provides information about the benefits of regular
guidelines. In March 2009, DC, the American Dietetic Association, and the American College of Sports
Nutrition published a joint position paper titled, Nutrition and Athletic Performance. The paper is available on
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Contributed by Gail Hammond.
between knowledge and behaviour on physical activity and educates Canadians about the importance of living a
healthy and active lifestyle.
to improve the effectiveness of coaching across all levels of the sport. Click on Sport Nutrition for their current
nutrition-related resources written for coaches and parents.
Highlight 14: Supplements as Ergogenic Aids
Many of the ergogenic aids described in this highlight are regulated in Canada under the Natural Health Products
Regulations.
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As noted in the Canadian Information section for Highlight 10 in this Instructor’s Manual—Vitamin
and Mineral Supplements—natural health products must be safe for consideration as over-the-counter products, be
available for self-care and self-selection, and not require a prescription to be sold. To learn about ergogenic products
and claims that are permitted in Canada, check the Natural Health Products Directorate web site.
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Worksheet 14-1: Cardiorespiratory Endurance Calculations
For each of the individuals below calculate the Maximum Heart Rate (MHR) and the Target Heart Rate Range
(THRR).
Individual
Maximum Heart Rate
Target Heart Rate Range
15 year old
50 year old
80 year old
30 year old
18 year old
45 year old
65 year old
* As one ages, the MHR decreases and the range between THRR narrows.
22 year old
12 year old
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Worksheet 14-2: Chapter 14 Crossword Puzzle
Across:
Down:
1. a below-normal body temperature
4. a decreased concentration of sodium in the blood
5. the volume of blood discharged by the heart each
minute (stroke volume X heart rate)
2. an above-normal body temperature
3. the amount of oxygenated blood the heart ejects
toward the tissues at each beat
4. the dangerous accumulation of body heat with
1 2
3
4
5 6
7
8
9
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Worksheet 14-3: Physical Activity Self-Evaluation
Fitness depends on a certain minimum amount of physical activity. Ideally, the quantity and quality of the physical
activity you select will improve your cardiorespiratory endurance, body composition, strength, and flexibility.
Examine your activity choices by keeping an activity diary for one week. For each physical activity, be sure to
record the type of activity, the level of intensity, and the duration. In addition, record the times and places of
beverage consumption and the types and amounts of beverages consumed. Now compare the choices you made in
your one-week activity diary to the guidelines for physical fitness.
1. How often were you engaged in aerobic activity to improve cardiorespiratory endurance? Was the intensity of
aerobic activity between 55 and 90 percent of your maximum heart rate? Did the duration for each session last
at least 20 minutes?
4. Do you drink plenty of fluids daily, especially water, before, during, and after physical activity?
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Worksheet 14-4: Fitness Review (Internet Exercise)
Go to the following website to answer questions 1-8:
1. The American College of Sports Medicine and the American Heart Association recommend that
healthy adults get a minimum of 60 minutes of moderate-intensity aerobic activity on five days each
2. Which of the following is NOT a benefit of regular physical activity?
3. According to CDC research findings obtained in 2001, with respect to cardiovascular disease, the
estimated direct medical cost was nearly $24 billion.
a. True
b. False
4. Any type of physical activity that meets the criteria of the “talk test” without a corresponding increase
5. Research has shown that swimming exercises substantially reduce the chance of developing heart
6. 30 minutes of moderate-intensity aerobic activity a day is the optimal level that one should seek to
achieve.
a. True
b. False
7. The Borg scale can be used to evaluate one’s perception of how hard one is exercising.
8. One benefit of strength training is that it increases lean body mass.