Physiology of Exercise

Exam 1

acute exposure to exercise

short term/ low intensity

chronic exposure to exercise

long term/ repetitive

exercise physiology

how the body functions under physical stress

physiology

study of the function of cells, tissues, organs, and systems

body systems

interrelated parts for a task/ complex

ACSM exercise

physical activity consisting of planned, repetitive movement done to improve or maintain physical fitness

ACSM physical activity

any bodily movement that results in energy burn

stress

the state of having a challenge to homeostasis

stress response

change from baseline homeostatic function (largely predictable)

change in heart rate

maintains 02 availability

change in sweating

maintain core temperature

change in ventilation

maintain gas levels in blood

change in glycogen breakdown

maintain energy availability in muscle cells

homeostasis

maintenance or a constant normal internal environment

is small fluctuation in body functions normal?

yes

the body maintains environment by controlling what factors

pH, blood gasses, ATP levels, temperature

homeostasis is BOTH

normal, stable environment AND normal, stable physiological functional

acute response

stress response (change in function) to meet the homeostatic challenge imposed by exercise

acute response is what happens in ________ term, single session

short

chronic response

what happens in long term, repeat exposure to acute stress

two functional ways the body responds to stress

control and signaling cascade

Control

Type of response that is predictable and proportional to change

Signaling Cascade

type of response that links acute exercise to chronic

what are the 2 chronic adaptations to exercise

exert greater homeostatic control to given stress, accumulate net protein synthesis for physical changes

mechanistic view of exercise

believes that doing specific physical activity causes specific adaptation, creates a new normal for them

dose-response view of exercise

take a “dose” or certain amount of exercise and you get this outcome

homeostatic perturbation

the thing that is disruption homeostasis

Formula for Work (J)

Work= force (N) x displacement (m)

Formula for Power

Power (W) = work (J) / time (s)

Energy

potential to do work or cause a change

Calorimetry

measure of energy expenditure

direct calorimetry

uses measurement of body heat production

indirect calorimetry

uses measured gas exchange (VO2 VCO2)

1 kcal = how many J?

4186 J

there is a predictable relationship between

external work rate (intensity) and internal energy expenditure

oxygen consumption is related to

metabolic rate

movement economy

the metabolic cost for physical activity to occur

homeostatic set point is

dynamic

Steady State

constant environment and constant physiological function, but not necessarily “normal” level

3 functions of control system

1. recognizing a set point

2. sensing change

3. altering function

2 types of control systems in the body

intracellular and organ

intracellular control systems

protein breakdown and synthesis, energy production, maintenance of stored nutrients

organ control systems

pulmonary and circulatory system, replenish oxygen and remove CO2

3 parts of a control system

1. control center

2. sensor

3. effector

Biological Control System

interconnected components that maintain a physical or chemical parameter at a near constant value

Sensor or receptor

detects changes in physical or chemical parameter

control center

assesses input and initiates response

effector

changes internal environment back to normal

Negative feedback

work of the effector is opposite of the initial stimulus

Gain

degree to which a control system can maintain homeostasis

Gain equation

gain = correction/ error

Large gain means

large magnitude of correction and small error while regulating

exercise can be viewed as a test of

homeostatic control

Strain

how challenged your physiology is in exerting control

Recovery Adaptation Process

regain what was lost, change in structure or function of cell or organ, improved ability to maintain control and stresses

recovery

regain what was lost

adaptation

change in structure and function of cell or organ systems

acclimation

adaptation to environmental stress

hormesis

exposure to low-moderate dose of potentially harmful stress that results in adaptation

General Adaptation System (GAS)

ability of an organism to adapt to stress over its lifetime

what are the 3 phases of the GAS system?

Alarm phase, resistance phase, exhaustion phase

Alarm Phase

temporarily reduced ability to overcome stress

Resistance Phase

positive adaptations: return to baseline or higher

Exhaustion phase

prolonged stress depletes resources, fatigue

Allostasis

Achieving stability through change

Allostatic Load

cumulative cost of long-term, repeated adaptation

Cell signaling pathways

promote acute response and chronic adaptation to exercise training

Intacrine

chemical messenger inside triggers response

juxtacrine

chemical messenger passed between two connected cells

autocrine

chemical messenger acts on that same cell

paracrine

chemical messengers act on nearby cells

endocrine

hormones released into blood act on cells with specific receptor

How do cell signals regulate protein synthesis?

by turning on and off specific genes

biomechanics reactions (metabolism) helps to regulate/ control

homeostasis

total metabolism

total volume of work completed total energy expended,

rate of metabolism

how much is done per unit of time, energy use per moment

type of metabolic reactions

processes to match the rate needed

metabolism

sum of all chemical reactions that occur in the body

reactants

go into the reaction

products

come out of the reaction

central unit of metabolism, energy currency

ATP

rate of atp use is proportional to

intensity of stress

primary factor for fitness

power output

explain more atp use effect on homeostatic control

more atp use- more o2 needed- strain on HR, respiration- greater substance delivery rate- strain on neuromuscular system

anabolic reactions

synthesis of molecules

endergonic

energy is added to reactions

exergonic

energy is cleaved or released

are anabolic reactions endergonic or exergonic?

endergonic

are catabolic reactions endergonic or exergonic?

exergonic

catabolic reactions

breakdown molecules (less complex)

give an example of a catabolic reaction

cellular oxidation of glucose, use glucose to release energy

give an example of an anabolic reaction

glucose built up to glycogen

ATP

adenosine triphosphate: biological energy carrier

3 forms of biological work

mechanical, chemical, transport

chemical work

synthesis of cellular molecules

mechanical work

muscle contractions

transport work

transport of substances

energy

potential to do work or cause a change

3 major ATP consumers in skeletal muscle

myosin crossbridge cycle, sarcoplasmic reticulum pumps, Na-K+ pumps

which consumes the most ATP

myosin crossbridge cycle and sliding filament consumes 70% of ATP