Physical Activity, Nutrients, and Body Adaptations

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 (boo!) that foster the development of several chronic diseases. [Then you die]

Benefits of Fitness Restful sleep Nutritional health Optimal body

composition Optimal bone

density Resistance to colds

and other infectious diseases

Lower risks of some types of cancer

Strong circulation and lung function

Lower risk of cardiovascular disease

Lower risk of type 2 diabetes Reduced risk of gallbladder

disease in women Lower incidence and severity

of anxiety and depression Long life and high quality of

life in the later years

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The 2005 Dietary Guidelines for Americans state that people need to participate in

30 minutes of physical activity most days of the week for health benefits and

60 minutes of physical activity most days of the week to maintain a healthy body weight.

THE 100-METER MOSEY

Before you criticize someone, you should walk

a mile in their shoes.

   That way, when you criticize them, you're a mile away and you have

their shoes

Developing Fitness Guidelines for conditioning that are

achieved through training. Cardiorespiratory Endurance

Frequency – 3-5 days per week Intensity – 55-90% maximum heart

rate Time/Duration – 20-60 minutes

Guidelines for conditioning Strength

Frequency – 2-3 days per week Intensity – enough to enhance muscle

strength, muscle endurance, and improve body composition

Time/Duration – 8 to 12 repetitions of 8 to 10 different exercises

I see no reason

Why You should not

engage in Strenuous

activity Well keep looking,

keep looking!

Guidelines for conditioning Flexibility

Frequency – 2-3 days per week Intensity – enough to develop and

maintain a full range of motion Time/Duration – 4 repetitions of 10-30

seconds per muscle group

Developing Fitness The Overload Principle – to slightly increase

comfortable capacity in each area. Also called the progressive overload principle.

Increase frequency – how often an activity is performed

Increase intensity – the degree of exertion while exercising

Increase time/duration – the length of time

Developing Fitness The Body’s Response to Physical Activity

Hypertrophy is muscle gain in size and strength, the result of repeated work.

Atrophy is muscle loss in size and strength, the result of lack of activity.

Other Tips Be active all week. Use proper equipment and attire. Use proper form when exercising. Include warm-ups and cool-downs. Challenge yourself, but not every time you exercise. Pay attention to body signals. Build intensity slowly.

Seven days without exercise makes one

weak!

Developing Fitness Cautions on Starting

Healthy people can start with a moderate exercise program without seeking medical advise first.

People with risk factors may need medical advice.

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Cardiorespiratory Endurance Cardiorespiratory conditioning is measured

by maximum oxygen uptake (VO2max). Increases cardiac output and oxygen

delivery Increases stroke volume Slows resting pulse Increases breathing efficiency Improves circulation Reduces blood pressure

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To prevent a heart attack, take one aspirin every day.

Take it for a walk, then take it to the gym,Then take it for a bike ride

Cardiorespiratory Endurance Muscle Conditioning

Muscles use oxygen efficiently. Muscles can burn fat longer.

A Balanced Fitness Program Individualized Cardiorespiratory Muscle strength and endurance Flexibility Choose an activity you enjoy

Weight Training Also called resistance training Increases muscle strength and endurance Prevents and manages cardiovascular

disease Enhances psychological well-being Maximizes and maintains bone mass Enhances performance in other sports

The Energy Systems of Physical Activity—ATP and CP ATP is adenosine triphosphate – a high-energy

compound that delivers energy instantaneously.

CP is creatine phosphate – a high-energy compound in the muscles, used anaerobically.

The Energy-Yielding Nutrients Nutrients work together while one may predominate. Depends on diet, intensity and duration of the

activity, and training

Extremely intense activity 8-10 seconds ATP-CP (immediately available) No oxygen needed (anaerobic) Activity example – 100 yard dash, shot put

Very highly intense activity 20 seconds to 3 minutes ATP from carbohydrate (lactic acid) No oxygen needed (anaerobic) Activity example – ¼ mile run at maximum speed

Highly intense activity 3-20 minutes ATP from carbohydrate Oxygen needed (aerobic) Activity example – cycling, swimming, running

Moderately intense activity More than 20 minutes ATP from fat Oxygen needed (aerobic) Activity example – hiking

Glucose Use during Physical Activity Diet Affects Glycogen Storage and Use

High-carbohydrate diets increase glycogen stores

Enhance endurance

Intensity of Activity Affects Glycogen Use Moderate activities use glycogen slowly.

Intense activities use glycogen quickly.

Glucose Use during Physical Activity Lactate

Low intensity activities can clear lactic acid from the blood.

During highly intense activities lactic acid accumulates and activity can only be maintained for 1-3 minutes.

Lactate is converted to glucose in the liver (Cori cycle). Duration of Activity Affects Glycogen Use

First 20 minutes – primarily use glycogen After 20 minutes – use glycogen and fat

Glucose Use during Physical Activity “Hitting the wall” – exhaustion of glucose stores Maximizing Glucose Supply

High-carbohydrate diet – 8 g/kg body weight or 70% of total energy intake

Glucose during activities if activity last longer than 45 minutes (sports drinks, diluted fruit juice)

Eat approximately 60 g of high-carbohydrate foods after activity.

Carbohydrate loading is a regime of diet and exercise that maximizes glycogen storage. It is also called glycogen loading or glycogen super compensation.

Glucose Use during Physical Activity Glucose during Activity

Activities lasting longer than 45 minutes Light carbohydrate snacks under 200 kcalories

Glucose after Activity High-carbohydrate meal within 15 minutes

accelerates glycogen storage by 300% High-carbohydrate meal within 2 hours and rate

of glycogen storage declines by half High-glycemic index foods

Glucose Use during Physical Activity Training Affects Glycogen Use

Muscles that repeatedly deplete glycogen through hard work will store greater amounts of glycogen.

Conditioned muscles rely less on glycogen and more on fat for energy.

Trained muscle cells have more mitochondria and can use oxygen better.

Untrained muscle cells depend more heavily on anaerobic pathways.

Fat Use during Physical Activity Duration of Activity Affects Fat Use

Beginning of activity uses fatty acids in the blood

After 20 minutes, uses body fat as major fuel Intensity of Activity Affects Fat Use

As intensity increases, fat makes less of a contribution to the fuel mix

Oxygen must be abundant to break down fat

Fat Use during Physical Activity Training Affects Fat Use

The better trained the muscles, the more fat is used

The better trained, the stronger the heart and lung to deliver oxygen

If better trained, then hormones prevent glucose release from the liver, so they rely more on fat

Protein Use during Physical Activity—and between Times Protein Used in Muscle Building

Synthesis of protein is suppressed during activity.

After activity protein synthesis accelerates. Repeated activities cause body adaptations to

support needs. Remodeling Daily, ¼ to 1 ounce of body protein is added to

muscle mass during muscle-building phase.

Protein Use during Physical Activity—and between Times Protein Used as Fuel

During physical activity muscles use amino acids for fuel. 10% of total fuel used

Diet Affects Protein Use during Activity Diets rich in energy and carbohydrate allow the

body to use less protein for fuel. Carbohydrates spare protein.

Protein Use during Physical Activity—and between Times Intensity and Duration of Activity Affect Protein

Use during Activity If glycogen stores get depleted, then more reliance on

protein Anaerobic strength training demands more protein to

build muscles but not large amounts. Training Affects Protein Use

The more trained the less protein used for energy

Protein Use during Physical Activity—and between Times Protein Recommendations for Active People

Athletes in training need more protein than sedentary people.

Athletes in training need to meet energy and carbohydrate needs first.

Adult RDA: for males 56 g/day, for females 44 g/day Strength athletes: for males 112-119 g/day, females 88-

94 g/day Endurance athletes: for males 84-112 g/day, females 66-

88 g/day U.S. average intake of protein: for males 95 g/day,

females 65 g/day

Vitamins and Minerals to Support Activity Supplements

Do not enhance performance Deficiencies may impede performance Timing makes a difference; supplements take

hours or days to combine with cells. Nutrient-dense foods provide nutrients needed.

Vitamins and Minerals to Support Activity Vitamin E

Protects against oxidative stress Does not improve performance More research needed Vegetables oils and antioxidant fruits and vegetables

Iron Iron losses in sweat Small blood losses in digestive tract Poor iron absorption

Vitamins and Minerals to Support Activity Iron Deficiency

Common in physically active young women Consume good dietary sources of iron

Iron-Deficiency Anemia Impairs physical performance Cannot perform aerobic activity and tire easily

Vitamins and Minerals to Support Activity Sports Anemia

Low blood hemoglobin for a short time Adaptive, temporary response to endurance

activity Does not require supplementation

Iron Recommendations for Athletes Blood tests should guide the decision Depends on the individual

Fluids and Electrolytes to Support Activity Fluid Losses via Sweat

Muscle heat is 15-20 times greater when active than at rest

Cooling mechanism 1 liter of sweat dissipates 600 kcalories of heat

Fluids and Electrolytes to Support Activity Hyperthermia – an above-normal body

temperature Body heat builds up Triggers maximum sweating without sweat

evaporation

Symptoms of heat stroke – a dangerous accumulation of body heat with accompanying loss of body fluid Headache Nausea Dizziness Clumsiness Stumbling Hot, dry skin Confusion or other mental changes

Prevention of heat stroke Drink fluids Rest in the shade when tired Wear appropriate clothing

Fluids and Electrolytes to Support Activity Hypothermia – a below-normal body temperature

Symptoms Shivering and euphoria Weakness, disorientation, and apathy

Prevention Drink fluids Wear appropriate clothing

Water Recommendations 1.0 to 1.5 mL/kcal expended ½ cup per 100 kcal expended

Fluids and Electrolytes to Support Activity Fluid Replacement via Hydration

Full hydration is imperative for athletes. Those who are aware of their hourly sweat rate can

replace lost fluids. Plain, cool water is recommended. Endurance athletes may require carbohydrate-containing

beverages. Hydration schedule

Two hours before activity – 2-3 cups 15 minutes before activity – 1-2 cups Every 15 minutes during activity – ½-2 cups After activity – 2 cups for every pound of body weight lost

Fluids and Electrolytes to Support Activity Electrolyte Losses and Replacement

Greater in the untrained Training improves electrolyte retention. Eat regular diet meeting energy and nutrient

needs Endurance athletes may need sports drinks. Salt tablets worsen dehydration and impair

performance.

Fluids and Electrolytes to Support Activity Hyponatremia

Decreased concentration of sodium in the blood Causes

Excessive sweat Overhydration Drinking sports drinks during an activity; sports

drinks offer glucose polymers

Symptoms of hyponatremia Severe headache Vomiting Bloating Confusion Seizure

Prevention of hyponatremia Replace sodium during prolonged

events. Do not restrict salt in diets the days

before events.

Poor Beverage Choices: Caffeine and Alcohol Caffeine is a stimulant. Alcohol is not the beverage to replace

fluids and carbohydrate.

A diet that provides ample fluids and nutrient-dense foods to meet energy needs will enhance an athlete’s activity and overall health.

Pregame and postgame meals should be light and carbohydrate rich.

Choosing a Diet to Support Fitness Water

Thirst mechanisms are not as reliable Must be replenished

Nutrient Density – consume nutrient-dense foods that are high in carbohydrate, moderate in fat, and adequate in protein

Choosing a Diet to Support Fitness Carbohydrate

60-70% total energy intake Avoid fiber-rich foods in the pregame meal. Added sugar and fat may be needed during intensive

training. Liquid supplements should not replace foods. 8-10 g carbohydrate/kg body weight during heavy training

Protein Strength athletes: for males 112-119 g/day, females 88-94

g/day Endurance athletes: for males 84-112 g/day, females 66-88

g/day

Choosing a Diet to Support Fitness A Performance Diet Example

Total kcalories – 3000 63% kcal from carbohydrate 22% kcal from fat 15% kcal from protein All vitamin and mineral RDAs are met

Meals Before and After Competition Pregame Meals

Fluids 300-800 kcalories Carbohydrate-rich foods low in fat and fiber Light and easy to digest

Postgame Meals High-carbohydrate meals Liquids often preferred

It is difficult to distinguish valid versus bogus claims about ergogenic aids.

Many individuals believe these drugs, supplements, or procedures will enhance physical performance in activities.

Some are harmless, some have dangerous side effects, and some are costly.

Most do not meet claims.

Substances promoted as ergogenic aids Arginine – a nonessential amino acid Boron – a nonessential mineral Brewer’s yeast is falsely promoted as

an energy booster. Cell salts are sold as health promoting. Coenzyme Q10 is not effective in

improving athlete performance. DNA (deoxyribonucleic acid) is falsely

promoted as an energy booster. Epoetin is illegally used to increase

oxygen capacity.

Substances promoted as ergogenic aids Gelatin is not a strength enhancer. Ginseng has many side effects. Glycine – a nonessential amino acid Growth hormone releasers do not enhance

performance. High doses of guarana can stress the heart and

cause panic attacks. Herbal steroids or plant sterols do not enhance

hormone activity. HMB (beta-hydroxy-beta methylbutyrate) claims to

increase muscle mass and strength. Inosine has been shown to reduce endurance of

runners.

Ma huang has many dangerous side effects.

Niacin does not enhance performance and has side effects.

Octacosanol has false promotions. Ornithine – a nonessential amino acid Pangamic acid does not speed oxygen

delivery. Phosphate pills do not extend endurance

or increase efficiency of aerobic metabolism. Pyruvate has common side effects of gas

and diarrhea.

Ribose has some false claims. RNA (ribonucleic acid) does not enhance

performance. Royal jelly is falsely promoted. Sodium bicarbonate may cause intestinal

bloating and diarrhea. Spirulina is potentially toxic. Succinate is not a metabolic enhancer. Superoxide dismutase (SOD) is useless; it is

digested. Wheat germ oil is not an energy aid.

Carnitine Non-essential nutrient Facilitates transfer of fatty acids across

mitochondria membranes Supplementation does not increase muscle

carnitine or enhance exercise performance. Chromium Picolinate

Essential mineral in carbohydrate and lipid metabolism

Supplementation has no effect on strength, lean body mass, or body fat.

Complete Nutrition Supplements Taste good and provide food energy, but do not

provide complete nutrition Should not replace regular meals

Creatine Some studies suggest improvement in muscle

strength and size, cell hydration and glycogen loading capacity

Safety issues and side effects

Conjugated Linoleic Acid (CLA) Derived from linoleic acid, an essential fatty acid Increases lean body mass in animals Few human studies have been performed.

Caffeine Caffeine can enhance performance by stimulating fatty acid

release. Adverse effects include stomach upset, nervousness,

irritability, headaches, and diarrhea. Use in moderation. Use as an addition to other fluids, not as replacement.

Oxygenated Water Oxygen cannot enter the bloodstream by way of the GI tract. The body gets oxygen from the lungs.

Anabolic Steroids Illegal Authorities ban use Plant sterols from herbs are poorly

absorbed. Dangerous side effects on the body and

the mind

DHEA (dehydroepiandrosterone) and Androstenedione Hormones that are precursors to testosterone No evidence to support claims Short-term effects are identified

Human Growth Hormone (hGH) Used to build lean tissue and increase height if

still growing Extremely high cost Many adverse side effects