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Lecture 4

PSY333H1 Lecture Notes - Lecture 4: Antigen, Coronary Artery Disease, Public Health Agency Of Canada

Course Code
Nevena Simic

of 10
Lecture 4 Health-Enhancing Behaviors
Health-Enhancing Behaviors
After looking at some of the attitudinal and
behavioral principles identified in Chapter 3, we are
going to look at how these principles may be applied
in health-enhancing behaviors
- Exercise
- Accident prevention
- Cancer prevention
- Healthy diet
- Weight control
- Sleep
Physical Activity: any skeletal muscle contraction
that results in an increased energy expenditure.
-Any physical activity (even fidgeting) will use
energy and burn calories.
Exercise: repetitive physical activity or movement
aimed at improving or maintain fitness or health.
Four Componenets of Physical Activity
1. Type: identifies the physiological systems used in a
particular activity
- Aerobic
- Strength
- Endurance
- Flexibility
2. Frequency: describes how much activity is performed
over a period of time.
3. Intensity: describes load imposed on physiological
4. Duration: temporal length of physical activity.
Does Type Matter?
Many different types of exercise or physical
activity…but physiologically there are 5 forms of
Resistance related
1. Isometric exercise- contract muscle group against
immovable object without movement in body (improves
muscle strength)
Example: planking
2. Isotonic exercise- place resistance on muscles by
moving muscle groups; e.g. weightlighting (improves
strength & endurance)
Example: push up
Lecture 4 Health-Enhancing Behaviors
3. Isokinetic exercise- place resistance that overloads
muscle groups through complete range of motion with
variable resistance; need special equipment (best for
strength and endurance)
Example: bicycle where you can change resistance to make
it like your going uphill
Other two forms are
1. Aerobic
2. Anaerobic
Energy for exercise comes from burning glucose and
fatty acids
- Can be in the presence of oxygen or not
Aerobic exercise
- Sustained exercise, prolonged oxygen (O2) use
-High intensity, long duration, high endurance
- Stimulates and strengths heart and lungs - - ->
improved body’s O2 usage
- Ex) Jogging, bicycling, swimming
Anaerobic exercise
- High-intensity, short-duration, low-endurance
- Creates deficit in O2
Example: sprinting
Exercise Physiology
Ability to perform physical work is dependent upon the
ability of the muscle to transform chemical energy
into mechanical energy
How Exercise Works
Muscles: source of energy that keeps everything going
is Adenosine triphosphate (ATP)
Biochemical way to store and use energy
- Adenine nucleotide bound to three phosphates
- Energy stores in the bond between the second and
third phosphate groups
When you take one away you are left with energy.
Your body uses the oxygen you breathe to make ATP. ATP
attaches to myosin and forced it to let go off actin.
Nerve impulses set off a biochemical reaction that
causes myosin to stick to actin.
The two molecules lock together, pulling the muscles
thick and thin filament toward each other.
How Does Body Create ATP?
Several different systems to create ATP
Lecture 4 Health-Enhancing Behaviors
Work together in phases
- Different forms of exercise use different systems,
so a sprinter is getting ATP in a completely different
way from a marathon runner
ATP comes from three different biochemical systems in
the muscle, in this order:
- Phosphagen system
- Glycogen-lactic acid system
- Aerobic respiration
Phosphagen System
Muscle cells contain a high-energy phosphate compound
called creatine phosphate
- Phosphate group is removed from creative phosphate
by an enzyme called creatine kinase, and is
transferred to ADP to form ATP
ATP levels and creatine phosphate levels = phosphagen
- Supply energy needs of working muscle at a high
rate, but only for 8 to 10 seconds
Glycogen-Lactic Acid System
Muscles have big reserves of a complex carbohydrate
called glycogen (chain of glucose molecules)
Cells splits glycogen into glucose - - -> uses
anaerobic metabolism (anaerobic means without
energy) to make ATP and a byproduct called lactic
acid from the glucose
12 chemical reactions take place to make ATP under
this process, so it supplies ATP at a slower rate than
phosphogen system
- Produce enough ATP to last about 90 seconds
Aerobic Respiration
When oxygen is present, glucose can be completely
broken down into carbon dioxide and water in a process
called aerobic respiration
Glucose can come from three different places:
- Remaining glycogen supplies in the muscles
- Breakdown of the liver’s glycogen into glucose,
which gets to working muscles through the bloodstream
- Absorption of glucose from food in the intestine,
which gets to working muscle through the bloodstream
Can also use fatty acids from fat reserves in muscle
and the body to produce ATP