Energy Expenditure Flashcards
rely on feedback from various body parts
and provide feedforward signals according to general
(autonomic, innate,learned) principles and according to
situation-dependent (voluntary, motivational) Rules.
Control Centers
control center of the body
Brain
provides oxygen for
energy metabolism and dissipates metabolic
by-products.
Respiratory System
- carries oxygen from
the lungs to cells that consume oxygen. - brings “fuel,
” that is,
derivatives of carbohydrates and fats to the
cells and removes metabolic by-products
from the combustion sites.
Circulatory System
supports the chemical
processes in the body, particularly those that
yield energy
Metabolic System
Volumes of _______ L of blood in women and _______ L in men are normal.
4 - 4.5
5- 6
Dissolved materials carried by blood
Oxygen
Nutrients
hormones
enzymes
salts,
vitamins
transport oxygen
through
hemoglobin,
an
iron containing
protein
molecule.
Red blood cells
reacts with oxygen and
carbon dioxide simultaneously, but
has high affinity for carbon monoxide,
causing its toxicity.
Hemoglobin
Architecture of the Circulatory System
Systemic Circuits
Pulmonary Circuits
Self regulating process by which
internal stability of human body is
maintained while adjusting to
conditions optimal for survival
Homeostasis
Overtime, Homeostasis achieves balance between input and output where :
Inputs are ______
Outputs are ______
Nutrients, Proteins, (Food Intake)
Work and Heat
measured in terms of physically useful energy (when we perform tasks)
Work
A portion of the energy consumed is lost as ____. This helps in maintaining body temperature.
Heat
Refers to all chemical processes in the living body
Describes the overall energy yielding process
Metabolism
Defined as the ratio of work performed and energy input
Work efficiency
Types of Reactions
Catabolism
Anabolism
________ is exothermic (output). Breaking down of complex molecules into numerous simple ones.
Catabolism
________ is endothermic (input). Building complex molecules from simple ones.
Anabolism
Primary source of quick energy, converted to
glucose.
Stored as glycogen in muscles and liver
Carbohydrates
Major energy reserve, stored in adipose tissue.
Digestion releases glycerol and fatty acids for
energy.
The carrier of vitamins a, d, e and K in food
Fats
Chains of amino acids for body functions
(enzymes, hemoglobin).
Used as energy source when other fuels are
depleted
Proteins
are the amount of food energy that should be eaten
to compensate for caloric expenditure.
Energy Requirements
refers to the amount of energy an individual uses to
maintain essential body function (respiration, circulation
and digestion) and as a result of physical activity.
Energy Expenditure
Components of Energy Expenditure
Basal Metabolic Rate (BMR)
The Thermic Effect of Food
Physical Activity
amount
of energy
the
body
needs to
maintain
basic
physiological
functions
while
at rest, such as breathing, circulation, cell
production, and nutrient processing.
Basal Metabolic Rate (BMR)
Factors that influence basal metabolic rate
Age
Body composition
Genetic factors
Gender
Hormonal Balance
Environment factors
Physical Activity levels
88.4 + (13.4 × weight it kg) +
(4.8 × height in cm) - (5.68 ×
age)
Male
447.6 +( 9.25 × weight in kg)
+ (3.10 × height in cm) - (4.33
× age)
Female
The amount of energy it takes for your body to digest, absorb,
and metabolise the food you eat.
Thermic Effect of Food (TEF)
Foods that have the Highest Thermic Effect
- Proteins 20%-30%
- Carbohydrates 5%-10%
- Fats 0%-5%
Normally represent between 20%-40% of the
energy expenditure.
It varies significantly between individuals on the
basis of the deployed activity. It is not constant
and depends on daily physical activity.
Physical Activities
is operationally defined as a “reduced
muscular ability to continue an existing effort.”
best researched in regard to maintained static
(isometric) muscle contraction.
Fatigue
Benefit of Fatigue
Prevention of serious damage
Given the same ratio of “total resting
time” to “total working time,
” many short
rest periods have more recovery value
than a few long rest periods.
True
Individual Factors
Age
Sex / Gender
Fitness Level
Body Mass Index
Health Status
Task Related Factors
Task Demands
Workload
Work Environment
Equipments / Tool Design
Environmental Factors
Climate/ Weather
Lighting
Vibration
Noise
Situation Specific Factors
Shift Work
Work Schedule
Travel/Commute
Work Home Interface
How to Calculate Physical Activity Expenditure
Physical Activity Expenditure = Activity x Time
A person’s oxygen consumption while performing work is a
measure of his or her _____________________________.
metabolic energy production
compares the
carbon dioxide expired with the oxygen consumed.
also called respiratory exchange rate RER
Respiratory Exchange Quotient (ROQ)
Tools for assessment of human energy capabilities
bicycle ergometers
treadmills
steps
Measuring Oxygen Uptake
Period of time
Physicians or Physiologist
Indirect Calorimetry
Counting Heart Rates
Palpation
PLETHYSMORGRAPHIC METHOD
ECG
How to compute power function
P = e + f ( I − g) ^n
___ ________ on a formal “light” to “hard”
scale can be used to measure the
intensity of a task.
RPE Scale
category scale with
ratio properties that yields ratios and levels
and allows comparisons but still retains the
same correlation (of about 0.88) with the heart
rate as the RPE scale, particularly if large
muscles are involved in the effort
General Scale
Energy Requirements
Metabolic Cost x Duration
Given the largely ________ relationship between heart rate and
energy uptake, one can often simply use the heart rate (see above) to label work as
“light” or “heavy.”
linear
▪︎
involves rhythmic muscle
contraction and relaxation
▪︎
blood flow is maintained
▪︎ Energy consumption is
significant and measurable
Dynamic Work
▪︎
involves sustained muscle
contraction
without significant movement
▪︎
blood flow occuluded
▪︎
energy consumption is lower
than perceived exertion
Static Work
Measures energy expenditure during
ascent. Varies based on incline and
climbing method
Oxygen Consumption
Indicates cardiovascular strain. Increases
with steeper angles amd more
challenging cimbs
Heart Rate Monitoring
user preferences and perceived effort.
Important for real-world application and
comfort
Subjective Ratings
Angle-based
recommendations for
vertical access
Ramps 0-20°
Stairs 20-50°
Stair Ladders 50-75°
Ladders above 75°
