Chemistry for Changing Times11th Edition

Hill and Kolb

Chapter 18

Fitness and Health

John Singer

Jackson Community College, Jackson, MI

© 2007 Prentice Hall

Calories: Quantity and Quality

Caloric reduction may be the key to a long life.

Caloric reduction has been demonstrated to promote longevity in mouse studies.

Humans seem to stay healthier when we eat less than when we overeat.

Calories: Quantity and Quality

Food Pyramid

Calories: Quantity and Quality

Fat IntakeMore than half of the fats in the American diet are animal fats and 70% of saturated fat comes from animal products.It is recommended that total fat intake should be between 20 and 35% of calories from fat. Most should be polyunsaturated fat. Less than 10% should be saturated fats, and trans fats should be minimized. Total cholesterol intake should be less than 300 mg/day.

Calories: Quantity and Quality

Dietary Reference Intake (DRI) is nutrition-based reference values established by the Food and Nutrition Board of the U.S. National Academy of Sciences for use in planning and assessing diets.

Calories: Quantity and Quality

Nutrition and the Athlete

Carbohydrates provide energy.

Muscle is built through exercise, not by consuming excess protein. As muscle contracts against resistance, the amino acid creatine is released. Creatine stimulates the production of the protein myosin that contributes to the construction of muscle tissue.

Vitamins and Minerals

Vitamins are organic substances that the human body needs but cannot manufacture.

Minerals are inorganic elements required by the body.

Vitamins and MineralsDRI Values of Vitamins and Minerals

Vitamins and Minerals

Vitamin A a fat-soluble vitamin that is essential for vision, bone development, skin maintenance, and may help resist cancers.

Most cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, and cabbage contain β-carotene that is converted to vitamin A by the body.

Vitamins and Minerals

B vitamins are a class of eight water-soluble vitamins important in maintaining the skin and nervous system. B vitamins include:Vitamin B3 (niacin) which helps lower blood cholesterol and provides relief from arthritis.Vitamin B6 (pyridoxine) which is a coenzyme for more than 100 different enzymes and has been found to be helpful in relieving arthritis.Vitamin B12 (cyanocobalamine) prevents pernicious anemia.Folic acid is critical to the nervous development of a fetus and may help prevent cardiovascular disease.

Vitamins and Minerals

Vitamin C is known as ascorbic acid. It is a water-soluble vitamin that serves a number of functions. It will prevent scurvy and promote the healing of wounds, burns, and lesions. It is important in maintaining collagen and is an antioxidant. In addition, it has been shown to increase the body’s production of interferons, which interfere with the growth of viruses.

Vitamins and Minerals

Vitamin D is a steroid-type vitamin that promotes absorption of calcium and phosphorus and helps promote healthy bones and prevent rickets.

Vitamins and Minerals

Vitamin E is a mixture of tocopherols. Vitamin E is an antioxidant that deactivates free radicals and has been used to treat coronary heart disease, angina, high blood pressure, varicose veins, and other cardiovascular problems.

Body Fluids and Electrolytes

Electrolytes are substances that form ions in solution and allow the solution to conduct electricity. In the human body, electrolytes are required by cells to maintain charge balance and control the flow of water molecules across the cell membrane. The main electrolytes are Na+, K+, Cl-, Ca2+, Mg2+, SO4

2-, HPO42-, and HCO3

-.

Body Fluids and Electrolytes

The best way to replace water lost through sweat, tears, respiration, and perspiration is to drink water.

Body Fluids and Electrolytes

Effects of Dehydration

Weight Loss Diets

Dieting is a major industry in the U.S.

One pound of adipose tissue = 3500 Cal.

Reduction caloric intake by 100 Cal/day would cause the loss of one pound of fat in 35 days.

Very low Calorie diets are likely to be deficient in proper nutrition.

Weight Loss Diets

Biochemistry of HungerGhrelin is an appetite stimulant peptide produced in the stomach.PYY is an appetite suppressant peptide.Leptin is a protein produced in fat cells. It promotes weight loss. Most obese humans have high blood levels of leptin and are resistant to its effects.Cholecystokin is a peptide produced in the intestine that signals when we have had enough to eat.

Weight Loss Diets

Crash Diets: Quick = Quack

Quick weight-loss programs often involve water loss to make the appearance of actual weight loss. Many people who participate in such programs will often regain their weight when the body is rehydrated.

Exercise for Weight Loss

Exercising increases the metabolic rate. This leads to proper fitness and weight-loss. The best way to lose excess weight is to eat a nutritious, low-calorie diet along with a consistent exercise program.

Measuring Fitness

Measuring fitness is usually to measure the amount of body fat. Percent body fat can be determined by measuring a person’s density, making measurements of a person’s waist and hips, or by bioelectric impedance analysis.

Measuring Fitness

Body mass index (BMI) is used as a measure of fatness.

BMI = 705 body wt (lbs)

[height (in)]2

Ideal BMI for adults is between 18.5 and 24.9. A BMI of 25-29.9 = overweight. Greater than 30 = obesity.

Measuring Fitness

VO2 Max: A Measure of Fitness

VO2 max is the maximum amount of oxygen, in mL, that a person can use in one minute per kilogram of body weight.

VO2 max can be estimated from the percent maximum heart rate (%MHR) as follows:

%MHR = (0.64 x % VO2 max) + 37

Some Chemistry of Muscles

The human body has about 600 muscles.

Exercise makes muscles larger, more flexible, and more efficient in their use of oxygen.

With regular exercise, one’s blood pressure and pulse remain lower, and the person is able to do more physical work with less strain. This is known as the training effect.

Some Chemistry of Muscles

Two proteins play an important role in muscle contraction, actin and myosin. Together they form a complex called actomyosin. The potential energy of ATP is converted to kinetic energy of muscle contraction.

Some Chemistry of Muscles

Aerobic Exercise: Plenty of Oxygen

During exercise, ATP in muscle tissue is consumed in a few minutes. The muscle tissue then consumes glycogen stores for energy. Under aerobic conditions, the glycogen is converted to pyruvic acid and oxidized to carbon dioxide and water.

Some Chemistry of Muscles

Anaerobic Exercise and Oxygen Debt

Under anaerobic conditions, the pyruvic acid is converted to lactic acid. The build up of lactic acid in muscle tissue leads to muscle fatigue.

Some Chemistry of Muscles

Muscle Fibers

Type I (slow-twitch) fibers have high myoglobin levels and therefore high respiratory capacity. They are used for light or moderate work and are active under aerobic conditions.

Type IIB (fast-twitch) fibers demonstrate a high level of glycogen use and can generate ATP rapidly. They are stronger and larger muscle fibers that are more suited for anaerobic activity.

Some Chemistry of Muscles

Some Chemistry of Muscles

Building MusclesEndurance exercise helps increase myoglobin levels but does not contribute to muscle mass. It favors the development of Type I muscle fibers.

Weight training helps build Type IIB muscle fibers but does not increase respiratory capacity.

Drugs and the Athlete

Restorative drugs are used to alleviate pain or soreness, or treat injuries. These restorative drugs include analgesics (painkillers) such as aspirin and acetominophen and anti-inflammatory drugs such as aspirin, ibuprofen, ketoprofen, and cortisone.

Drugs and the Athlete

Stimulant drugs are used to enhance performance. These include caffeine, amphetamines, and cocaine. Stimulants mask symptoms of fatigue and give athletes a sense of increased stamina.

Drugs and the Athlete

Anabolic steroids include testosterone and its semisynthetic derivatives. They are used to increase muscle mass rapidly. Side effects of taking anabolic steroids include testicular atrophy, impotence, acne, and liver damage, as well as potential cancer, and growth of breasts.

Drugs and the Athlete

The use of drugs to improve athletic performance is unsafe and illegal. Many competitions include drug screening to detect the use of performance-enhancing drugs.

Exercise and the BrainExercising causes the body to release pain relieving endorphins to the blood. These endorphins are the cause of what is known as the “runner’s high.”

Exercise also increases blood flow to the brain and causes the production of neurotrophins which enhance the growth of brain cells.

Exercise is good for both the mind and body.

No SmokingTobacco smoke contains more than 4000 chemical substances. Tobacco use has been linked to cancer, heart disease, emphysema, and premature death. Smoking during pregnancy can lead to stillbirth, premature birth, and death of the newborn child. Exposure to second-hand smoke causes an estimated 3000 premature deaths each year in the U.S.

No Smoking