Benefits
of Aerobic Exercise
The major objective in
training is to cause biologic adaptations in order to improve
performance in a specific ask. This requires adherence to
carefully planned and executed activities. Attention is
focused on factors such as frequency and length of workouts, type of
training, speed, intensity, duration, and repetition of the activity.
To enhance physiologic improvement effectively and to bring
about a training change, a specific exercise overload must be applied.
By exercising at a level above normal, a variety of
training adaptations take place that cause the body to function more
efficiently.
Aerobic
System Adaptations
- Increased ability to produce
energy (ATP) by cellular mitochondria
- Increased intracellular
aerobic system enzymes and mitochondria to produce ATP
- Skeletal muscle myoglobin
content may increase up to 80% facilitating oxygenation
- Increased capacity of
the muscle to mobilize and oxidize fat
- Greater capacity to oxidize
carbohydrates and store carbohydrates as glycogen
- Hypertrophy of different
muscle fibres depending on the type of training
Cardiovascular and
Respiratory Changes
- Heart Size.
The weight and volume of the heart increases with
long term aerobic training due to enlargement of the left ventrical and
thickening of its walls.
- Blood Volume.
Plasma volume and total hemoglobin increase with endurance
training thereby enhancing circulatory and thermoregulatory dynamics to
facilitate oxygen delivery.
- Heart Rate.
Resting and submaximal heart rate decreases.
This is especially true for previously sedentary individuals.
- Stroke Volume.
The hearts stroke volume increases significantly in endurance
athletes as a result of increased heart volume and enhanced myocardial
contractility.
- Cardiac Output.
The heart's increased outflow capacity with training is a
direct result of improved stroke volume.
- Oxygen Extraction.
Training produces significant increases in the amount of
oxygen extracted from the blood stream. This is the result of more
effective distribution of cardiac output to working muscles and of
enhanced capacity of the trained muscle cells to extract and utilize
oxygen.
- Blood Flow and Distribution.
As the cell's ability to deliver, extract, and utilize
oxygen increases, less regional blood flow is required to meet the
muscle's oxygen needs.
- Blood Pressure.
Regular aerobic training tends to reduce blood pressure
during rest and submaximal exercise. The larges decreases
occur in systolic pressure and are most apparent in hypertensive
individuals.
- Respiratory Function. In
submaximal exercise the trained individual ventilates less than prior
to training reflecting increased efficiency.
As a general rule,
aerobic capacity improves if exercise is of sufficient intensity to
increase heat rate to about 70 % of maximum.
Exercise need not be
strenuous in order to obtain positive results. An exercise
heart rate of 70% maximum represents moderate exercise that can be
continued for a long time with little or no discomfort. This
training level is commonly referred to as "conversational exercise" in
that it is sufficiently intense to stimulate a training effect yet not
so strenuous that it limits a person from talking during the workout.
It is unnecessary to exercise above this heart rate to
improve physiologic capacity. To keep pace with the training
effects, the work rate must be increased periodically to achieve the
threshold heart rate or whatever target heart rate has been
established. A person who began training by walking now has
to walk more briskly; this is gradually replaced by jogging for periods
of the workout and, eventually, continuous running required to achieve
the same relative strenuousness at the desired target heart rate.
If the progression in exercise intensity is not matched with
training improvements, the exercise program essentially becomes a
"maintenance" program for aerobic fitness.
What is a Calorie?
A calorie is a measure used to express the heat
or energy value of food and physical activity. It is defined
as the amount of heat necessary to raise the temperature of 1
litre of water 1 degree Celsius from 14.5 -15.5 degrees C.
For example if 300 Calories is
the caloric value of a particular food, then the energy trapped within
the chemical bonds of this food, if released, would change the
temperature of 300 litres of water by 1 degree C.
Utilizing
established medical research, we can
calculate an estimate amount of calories burned from running.
Calculate
the Calories You've Burned
What is a Body Mass Index?
The body mass index is
calculated from a person's height and weight,
is a reliable indicator of "fatness" in sedentary individuals, and can
be used to identify health
risks. The BMI is the person's weight divided by the square of the
height:
It is meant to be used
as a simple means of classifying sedentary individuals with
an average body composition. For these individuals, the
current value settings are as follows: a BMI of 18.5 to 25 may indicate
optimal weight; a BMI lower than 18.5 suggests the person is underweight, while a number above 25 may
indicate the person is overweight; a BMI below 15 may suggest the
person has an eating disorder; a number above 30 indicates
that the person is obese (over 40, morbidly obese).
Accuracy of this
measure is compromised by variable body composition, fitness level,
muscle mass, bone mass, gender, etc.
Calculate Your Body Mass Index