1. EXERCISE PHYSIOLOGY
Department of Physiology
Faculty of Medicine
Universitas Sumatera utara

2. Systemic Responses to
Exercise

3. NEUROMUSCULAR FUNCTIONS AND
ADAPTATIONS TO EXERCISE
 Exercise maintains neuronal health by improving
blood flow to the brain and by increasing brain
levels of growth factors that promote optimal
function of neurons.
 Recent study in humans has concluded that
exercise improves brain function and reduces the
risk of cognitive impairment associated with aging.

4. NEUROMUSCULAR FUNCTIONS AND
ADAPTATIONS TO EXERCISE
 Humans skeletal muscle can be divided into several
different classes based on the histochemical or
biochemical characteristics of the individual fibers.
 Neural adaptations:
↑ maximal motor unit recruitment
↑ synchronous recruitment of motor units

6.  SO motor units are recruited first during incremental
exercise, followed by a progressive increase in
FOG and FG motor unit recruitment as exercise
intensity increases.
 Both endurance and resistance exercise training
have been shown to promote a fast-to-slow shift in
skeletal muscle fiber types but does not result in
complete transformation of all fast fibers.
 Training adaptations: increases in muscle size from
hypertrophy and hyperplasia.

7. METABOLIC RESPONSES TO EXERCISE:
INFLUENCE OF DURATION AND INTENSITY
Short-term, Intense Exercise
• During high-intensity, short-term exercise (i.e., two
to twenty seconds), the muscles’ ATP production is
dominated by the ATP-PS system.
• Intense exercise lasting more than twenty seconds
relies more on anaerobic glycolysis to produce
much of the needed ATP.
• High-intensity events lasting longer than forty-five
seconds use a combination of the ATP-PC system,
glycolysis, and the aerobic system to produce the
needed ATP for muscular contraction.

8. METABOLIC RESPONSES TO EXERCISE:
INFLUENCE OF DURATION AND INTENSITY
Prolonged Exercise
 The energy to perform prolonged exercise (i.e.,
more than ten minutes) comes primarily from
aerobic metabolism.
 A steady-state O2 uptake can generally be
maintained during prolonged, low-intensity
exercise.

9. METABOLIC RESPONSES TO EXERCISE:
INFLUENCE OF DURATION AND INTENSITY
Incremental Exercise
• The maximal capacity to transport and utilize O2
during exercise (maximal oxygen uptake, or VO2
max) is considered to be the most valid
measurement of cardiovascular fitness.
• Indeed, incremental exercise test (also called
graded exercise test) are often employed to
determine a subject’s cardiovascular fitness.
• These tests are usually conducted on a treadmill or
a cycle ergometer.

11. • Oxygen uptake increase in linear fashion during
incremental exercise until VO2 max is reached.
• The physiological factors that influence VO2 max
include:
– The maximum ability of the cardiorespiratory system to
deliver oxygen to the contracting muscle.
– The muscle’s ability to take up the oxygen and produce
ATP aerobically.

14. CARDIOVASCULAR FUNCTIONS AND
ADAPTATIONS TO EXERCISE
 With the start of exercise, cardiovascular function
changes by:
↑ Heart rate
↑ Ejection fraction
↑ Stroke volume
↑ Cardiac output
↑ Redistribution of Q in favor of contracting skeletal
muscle
↓ Vascular resistance
↑ Muscle blood flow

16.  Muscle Contraction
 Venous Return
 End Diastolic Volume  Contractility
 Stroke Volume  Heart
Rate
 Cardiac Output
 Cellular Respiration
Sympathetic
Stimulation
 Muscle Vascular
Resistance
 Muscle Blood
Flow
 a-vO2∆
 Oxygen Extraction
 Oxygen ConsumptionAcute cardiovascular
adaptations that combine to
increase oxygen
consumption during
exercise

17. CARDIOVASCULAR FUNCTIONS AND
ADAPTATIONS TO EXERCISE
 Cardiovascular adaptations to training are
extremely important for improving endurance
exercise performance, and preventing
cardiovascular disease
 The more important of these adaptations are:
↑ Plasma volume
↑ Red cell mass
↑ Total blood volume
↓ Systolic and diastolic blood pressire
↑ End diastolic dimensions and ventricular volumes
↑ Maximal stroke volume
↑ Maximal cardiac output

18. Training For
Long -Term Endurance
 Plasma Volume  Red Cell
Mass
 Blood Volume
 Venous Return  Ventricular Volume
 End Diastolic Volume
 Maximal Stroke Volume
 Muscle Capillary Density
 Maximal Muscle Blood Flow
 Oxygen Delivery
 VO2max
Exercise to VO2max
 Maximal Cardiac Output
Chronic adaptations
of the CV system
after exposure to
training for long
term endurance.
Adaptations are
related to their
affect during both
maximal &
submaximal
exercise

19. Training For
Long-Term Endurance
 Plasma Volume  Red Cell Mass
 Blood Volume
 Venous Return  Ventricular Volume
 End Diastolic
Volume
 Stroke Volume  Sympathetic Stimulation
 Heart Rate
Submaximal
Steady State Exercise
Chronic adaptations
of the CV system
after exposure to
training for long
term endurance.
Adaptations are
related to their
affect during both
maximal &
submaximal
exercise

20. PULMONARY ADAPTATIONS TO EXERCISE
 After the onset of exercise there is:
A rapid ↑ in ventilation
A similar rapid ↑ in pulmonary blood flow
An improved VE vs Q relationship in the lung
↑ Lung compliance
Airway dilation and ↓ resistance to air flow
 The lungs and pulmonary circulation do not express
the degree of long-term adaptations to exercise.
The improvement are more determined by
muscular and cardiovascular function.

22. Endocrine Adaptations to
Exercise