Transcript Chemistry for Changing Times 11th Edition Hill and Kolb

Chemistry for Changing Times
11th 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 Intake
More 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 Minerals
DRI 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+, SO42-, 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 Hunger
Ghrelin 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 weightloss. 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 Muscles
Endurance 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 Brain
Exercising 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 Smoking
Tobacco 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