Chapter 13
• Fitness: 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. 4
• The cardiorespiratory system includes the circulatory and respiratory systems, delivering oxygen and nutrients to the cells.
• Hypertrophy: an increase in the size of a muscle or organ.
• Atrophy: wasting or decrease in the size of a muscle or other tissue caused by lack of use.
Over 4 in 5 Canadians are not meeting physical activity recommendations.
• Because of the impact of physical activity on health, the Canadian government has launched initiatives to increase activity: o Canada’s Physical Activity Guide o ParticipACTION (relaunched) Physical Activity Levels of Canadians Regular aerobic exercise strengthens the heart muscle, increases stroke volume, decreases the resting heart rate. • Resting heart rate can be measured by counting the number of pulses per minute while at rest.
•Aerobic capacity: The body’s maximum ability to generate ATP by aerobic metabolism during exercise. Also called VO2 max.
• Hypertrophy: when stress or overload during exercise causes muscles to adapt by increasing in size and strength.
• 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:
o Weight management
o Cardiovascular health
o Diabetes prevention or management
o Bone and joint health
o Possible reduction of cancer risk
o Psychological health Target Heart Rates During Exercise
Starting and Maintaining an Exercise Program
• Start slowly. Set specific attainable goals. Once you have met them, add more.
• Make exercise fun and convenient.
• Stay motivated.
• Keep your exercise safe.
Fuelling Exercise
• Aerobic metabolism: metabolism in the presence of oxygen.
o Glucose, fatty acids, and amino acids are completely broken down to form CO2 and H20 and to produce ATP.
• Anaerobic metabolism: metabolism in the absence of oxygen.
o Each molecule of glucose produces two molecules of ATP.
o Glucose is metabolized in this way when oxygen cannot be supplied quickly enough to the tissues to support aerobic metabolism.
o Also called anaerobic glycolysis. Oxygen Delivery to Muscle
Relationship of Exercise to Intake
•In an athlete’s diet, the source of dietary energy can be as important as the amount of energy.
• Vitamins and minerals requiring special attention from athletes: o B vitamins o Antioxidant vitamins (e.g., vitamins C and E) o Iron o Calcium
• The general proportion of energy for athletes and healthy individuals should be: o 45-65% total energy from carbohydrates o 20-35% from fat o 10-35% from protein
Sports anemia: Reduced hemoglobin levels that occur as part of a beneficial adaptation to aerobic exercise in which expanded plasma volume dilutes red blood cells. 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.
• 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.
Recommended Fluid Intake
Before Exercise
• Begin exercise well hydrated by consuming generous amounts of fluid in the 24 hours before exercise.
• Consume 5 to 10 ml/kg body weight of fluids 2 to 4 hours before exercise.
During Exercise
• Consume water to replace losses from sweating, typically 0.4 to 0.8 L per hour.
• For exercise lasting 60 minutes or less, plain water is the only fluid needed but beverages containing carbohydrate and electrolytes will not hurt performance.
• For exercise lasting longer than 60 minutes, consuming a fluid containing about 6%–8% carbohydrate may improve endurance.
• For exercise lasting longer than 60 minutes, a fluid containing electrolytes can increase fluid intake by stimulating thirst and increasing absorption.
After Exercise
• Begin fluid replacement immediately after exercise.
• Consume 500–750 ml (16–24 ounces) of fluid for each 0.5 kg (1 lb) of weight lost. Hyponatremia
Evaluating the Benefits and Risks of Ergogenic Supplements
• Follow the recommended dose on the label. More isn’t always better and may cause side effects. How much does it cost? • More expensive is not always better. • Compare costs and ingredients before you buy.
Claims, Benefits, and Risks of Popular Ergogenic Aids
Ergogenic Aid
Media Claims, Often Unsubstantiated
Proven Benefits
Potential Risks
Used as Natural Health Product?
Arginine, ornithine, and lysine
Causes the release of growth hormone, which stimulates muscle development and decreases body fat.
No increase in lean body mass observed with supplementation.
Reduced absorption of other amino acids. Diarrhea at high doses.
Yes; arginine is cleared to support modest improvementsin exercise capacity in individuals with stable cardiovascular disease.
Bee pollen
Causes faster recovery from training workouts, which enables a higher level of training.
No evidence that it improves training level.
Allergic reactions.
Yes, a minor ingredient in many multi-ingredient preparations.
Bicarbonate (sodium bicarbonate, baking soda)
Helps buffer lactic acid produced during exercise and delays fatigue.
Increases blood pH and may enhance performance and strength during intense anaerobic activities.
Causes bloating, diarrhea, and high blood pH.
No, common food ingredient.
Branched-chain amino acids (leucine, isoleucine, and valine)
Improves endurance and prevents fatigue.
Evidence of an effect is inconsistent.
No toxicity reported.
Yes, pre-cleared to be used in support of protein maintenance.
Caffeine
Increases the release of fatty acids from adipose tissue, spares glycogen, and enhances endurance.
Increases endurance in some individuals.
Dehydration, nervousness, anxiety, insomnia, digestive discomfort, abnormal heartbeat.
Yes, pre-cleared for use to promote energy. Claims, Benefits, and Risks of Popular Ergogenic Aids (2 of 3) TABLE 13.5 Claims, Benefits, and Risks of Popular Ergogenic Aids
Ergogenic Aid
Media Claims, Often Unsubstantiated
Proven Benefits
Potential Risks
Used as Natural Health Product?
L-Carnitine
Enhances the utilization of fatty acids and spares glycogen.
No increase in fatty acid utilization or improvement in exercise performance found.
D,L-carnitine and D-carnitine forms can be toxic.
Yes, pre-cleared as an aid in recovery from muscle fatigue.
Chromium (chromium picolinate)
Increases lean body mass, decreases body fat, delays fatigue.
No effect on protein or lipid metabolism unless a chromium deficiency exists.
No toxicity reported in humans.
Yes, pre-cleared to support healthy glucose metabolism.
Coenzyme Q10
Increases mitochondrial ATP production, acts as an antioxidant, and may combat fatigue.
No effect on exercise performance observed.
No toxicity reported.
Yes, pre-cleared to maintain cardiovascular health.
Creatine (creatine monohydrate)
Increases ATP production and speeds recovery after high-intensity exercise.
Increases muscle creatine and creatine phosphate synthesis after exercise. Enhances strength, performance, and recovery from high-intensity exercise.
Stomach pain.
Yes, pre-cleared to increase muscle mass and strength during resistance training.
Ginseng (Panax ginseng or Chinese ginseng)
Enhances performance.
Little evidence of ergogenic effects.
May increase the effects and side effects of other stimulants such as caffeine.
Yes, pre-cleared for a variety of traditional uses including to enhance physical capacity.
Ergogenic Aid
Media Claims, Often Unsubstantiated
Proven Benefits
Potential Risks
Used as Natural Health Product?
Glutamine
Increases muscle glycogen deposition following intense exercise, enhances immune function, and prevents the adverse effects of overtraining.
Little evidence that glutamine increases immune function, prevents the symptoms of overtraining, or increases glycogen synthesis.
No evidence of toxicity.
Yes, pre-cleared for muscle cell repair and recovery from physical stress.
Glycerol
Improves hydration and endurance.
Evidence of an effect is equivocal.
May cause cellular dehydration, nausea, vomiting, diarrhea.
Yes, as a laxative, not for any exercise-related use.
HMB (β-hydroxy-β-methylbutyrate)
Increases ability to build muscle and burn fat in response to exercise.
Some evidence of an increase in lean body mass and strength.
No toxicity in animals, but little information in humans.
Yes, pre-cleared for enhancing strength in untrained individuals during intense resistance training.
Medium-chain triglycerides (MCTs)
Provides energy without promoting fat deposition; reduces muscle protein breakdown during prolonged exercise.
Provides energy, readily metabolized rather than stored as body fat. They increase endurance and fatty acid oxidation in mice, but there is no evidence of a benefit in humans.
None known.
No, used as a non-medicinal ingredient in some natural health products.
Ribose
Increases cellular ATP and muscular power.
No research.
None known.
Yes, pre-cleared as a carbohydrate in workout supplements.
Vanadium (vanadyl sulfate)
Aids insulin action; allows more rapid and intense muscle pumping for body builders.
No evidence to support a benefit for body builders.
Reduces insulin production.
Yes, most commonly part of a multivitamin mineral supplement for the maintenance of health. Banned Ergogenic Aids TABLE 13.6 Banned Ergogenic Aids
Ergogenic Aid
Claim/Effectiveness
Adverse Effects
Amphetamines (beans or greenies)
Decreases reaction time and increases endurance
Anxiety, irregular heartbeat, hallucinations, addiction, death
Anabolic steroids (testosterone or “T”)
Increases muscle mass and strength, decreases body fat
Testicular atrophy, liver damage, heart disease, hypertension
Androstenedione (andro)
Increases testosterone production leading to increased muscle mass and strength
Unknown; may increase cardiovascular risk and cause side effects similar to anabolic steroids
Ephedra (ma huang, guarana)
Boosts metabolism, burns fat, increases alertness, increases endurance
Anxiety, irregular heartbeat, hallucinations, addiction
Erythropoietin (EPO)
Increases endurance, increases oxygen-carrying capacity of the blood
Increased blood viscosity, increased risk of heart attack, or pulmonary embolism
Human growth hormone (HGH)
Stimulates body growth to increase muscle mass
Muscle and cardiac abnormalities, carpal tunnel syndrome, abnormal growth
What are three things a person needs to do according to Canadian Physical Guidelines?
- Aerobic training- 10 mins (150 mins per week) cardio
- Bone and muscle training- 2 days a week strength
- Flexibility training- warm up basic stretching. 5 mins warm-up
How to keep your exercise safe?
- stretching