1.2.2 - The
cardiovascular
system during
exercise
The cardiovascular
system
The cardiovascular system is made up of:
o
o
o
The Heart
Blood
Blood Vessels
The heart is a muscular pump that pushes the blood around
the body through the blood vessels to the working
muscles.
There are 3 blood vessels:
Arteries
Capillaries
Veins
Comparing arteries and veins
Arteries
Veins
Take blood away from the heart
Take blood to the heart
Walls are thick and elastic
Walls are thin
Transport oxygenated blood
Transports de-oxygenated blood
Has small lumen
Has large lumen
Has a pulse and blood travels
Has no pulse and blood travels
in spurts
smoothly
Has no valves
Has valves
Blood provides a link between all the other tissues and organs of the body. The
cardiovascular system also regulates body heat.
It has the capacity to carry essential items around the body.
These are
1.
2.
3.
4.
Oxygen from lungs around body to muscles
Waste carbon dioxide from body back to lungs
Glucose and nutrients from digestive system to cells
To transport nutrients and hormones around the body
Blood pressure
Blood is pumped out of the heart under pressure.
Pressure is calculated by measuring the pressure needed to stop the flow of
blood through an artery.
Two readings are taken, the systolic pressure when the heart contracts and
the diastolic pressure when the heart relaxes.
This is given as a number.
120/80 is the average reading for a young adult.
Blood pressure can be used as an indicator of general health.
Constant high blood pressure is known as hypertension and has become
associated with a number of cardiovascular diseases.
This is usually caused by a restriction of blood through the arteries making the
heart work harder to move blood around the body.
What happens to the cardiovascular system during exercise
You need to know the immediate, short term and long term effects of ecercise
on the Cardiovascular system.
We use our heart as a guide when training to see how hard our body is
working. We measure our heart rate in beats per minute (BPM).
Definitions
Blood pressure - 'the force exerted by circulating blood on the walls of the
blood vessels.'
Heart rate - 'The number of times the heart beats per minute'
Stroke volume - 'the volume of blood pumped out of the heart by
each ventricle during one contraction'
Cardiac output - 'the amount of blood ejected from the heart in one minute'
Resting heart rate
The average heart rate when we are at rest is 60-80 BPM
Your resting heart rate can be a sign of fitness. people with high cardiovascular
fitness have lower resting heart rates as the body is more efficient at
transporting the blood around the body.
Immediate effects of exercise on the
cardiovascular system
Adrenaline released
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Heart rate increases and contracts more strongly
Breathing becomes faster and deeper
Body temperature increases
Blood pressure rises
Sweating starts and the body requires replacement fluids
Exercise makes the body work harder. When we exercise the body releases
adrenaline. Adrenaline causes our heart rate to increase and glycogen
stores to be released into the blood.
Working muscles need a supply of oxygen and glycogen to make
energy and create movement. The more the muscles are used the
more glycogen and oxygen is needed. As the chemical reactions
occur in our muscles heat is also produced.
As we exercise we breathe deeper to get more oxygen
into the blood, our heart beats quicker and harder to
get that oxygen to the working muscles and we sweat to
try and cool the body down.
To help our body cool down our blood is redirected closer to the skin so that
heat can easily be lost. This is why we become red when we exercise.
Long term effects of regular exercise on the
cardiovascular system
Regular or long term participation in physical activity has many benefits, the
most important of which is that the heart becomes more efficient.
The benefits of regular exercise are:
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Size and volume of the heart increases
Lower resting heart rate
Lower blood pressure
Good recovery rate (returning to resting heart rate quicker)
Increased stroke volume (the heart pumps more blood per
beat)
Veins & Arteries become healthier reducing the risk of
coronary heart disease
More capillaries in muscles (more areas to exchange oxygen)
The resting heart rate gives an indication of fitness. This is because the heart is
a muscle. As you train it the heart becomes bigger and stronger. This means it
can push more blood out per beat and doesn't have to beat as many times to
deliver the same amount as it used to.
This graph shows the difference between the heart rate of a fit person who
exercises regularly and someone who does not exercise. You can see the
following:
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The fit person has a lower resting heart rate, before they begin to
exercise
The fit persons heart rate rises more slowly
The maximum heart rate reached by the fit person is a lot lower than the
unfit person
The fit persons heart rate drops quicker when they finish exercise
The heart rate of the fit person returns to their resting heart rate in a
quicker time
Remember - training thresholds use your heart rate to plan training
Can you remember how to figure out your maximum heart rate?
220-your age
Do you know your training thresholds?
Aerobic – 60-80%
Anaerobic 80% plus
Aerobic and anaerobic training and exercise
Training and exercise for CARDIOVASCULAR FITNESS can be aerobic,
anaerobic or a combination of both, but whatever method is used, certain
effects will be brought and these include:
Aerobic respiration
•Aerobic respiration happens in the cells of the working muscles. Aerobic
respiration is the process of making energy from glycogen combined with a
good supply of oxygen.
Glucose + Oxygen = Carbon Dioxide, Water, Energy
C6H12O6 + 6 O2 = 6 CO2 + 6 H2O + energy
Aerobic fitness is the ability to exercise or compete for a long time without
getting breathless.
AEROBIC FITNESS will help in the endurance events and games that go
on for long periods of time, examples include swimming, squash, tennis,
football and rugby.
Anaerobic respiration
Anaerobic respiration also happens in the cells of the working muscles.
Anaerobic respiration is the process of making energy from glucose in the
absence of Oxygen.
Anaerobic exercise can only supply quick bursts of energy. Working with
Anaerobic Respiration alone can only supply energy for about 10-15sec, about
the time it takes to run a 100m race.
Glucose = Energy, Carbon Dioxide, Lactic Acid
C6H12O6 = Energy +2CO2 +2C2H5OH
ANAEROBIC FITNESS is the ability to work at a high intensity for a short
period of time.
ANAEROBIC FITNESS will help in the activities where shorter, faster bursts
of energy are required, examples include sprint events up to 400m, shorter
races in swimming and any sprints in the games mentioned above where a
combination of aerobic and anaerobic fitness is required.
Lactic acid
When we work hard over 80% of our maximum heart rate, our body produces
energy through anaerobic respiration. Anaerobic respiration makes energy
without oxygen. It is a
you the anaerobic our muscles work and produce energy through aerobic and
anaerobic respiration lactic acid body works up to 75% of its maximum work
rate then lactic acid
Lactic acid is a poison. It builds up slowly during exercise that is up to 75% of
maximum work rate. During higher intensity work it builds up much more
quickly.
If you train you improve your muscles ability to produce energy and they work
more effectively. Lactic acid can also occur when glycogen stores begin to run
low in the muscles after prolonged exercise.
After a while lactic acid makes the muscles ache. It will eventually
cause cramp and the muscles will stop working. Athletes need to
rest while the blood brings fresh supplies of oxygen.
Oxygen debt
•When we produce energy through Anaerobic respiration we are doing so with
out the use of Oxygen. Our body then needs to recover and take on oxygen
before the muscles can work properly again. The repayment comes in the form
of gasping breaths at the end of an activity.
•This is to enable as much oxygen as possible to get back into the respiratory
system and to eliminate as much of the waste product as possible (lactic Acid).
Definition
Oxygen debt – the amount of oxygen consumed during recovery above that
which would have ordinarily been consumed in the same time at rest (this
results in a shortfall in the oxygen available).
The effect of lifestyle on the
cardiovascular system.
Rest
When athletes train it is really important for them to allow time to rest so the
body can repair and recover. This is particularly important after cardiovascular
training sessions. Rest allows the heart to grow and thicken in size and allows
the capillary network to grow.
When you start training you should allow the body one day rest after a
cardiovascular training session.
As you get fitter and stronger you can reduce the amount of rest days a week
you need.
Damage to the cardiovascular system
There are a few lifestyle traits than can have negative effects on the
cardiovascular system and can increase the chance of developing coronary
heart disease. These are:High cholesterol
Recreational drugs
Sedentary lifestyle and lack of exercise
Stress
High cholesterol
Your body needs cholesterol but there are 2 types
Bad - Low-density lipoprotein (LDL) - to much can clog up your arteries and
put strain on your cardiovascular sytem.
Good - High-density lipoprotein (HDL) - helps keep arteries clear and break
down LDL's. Can be increased with exercising.
Eating foods that are high in fat increases your cholesterol intake. Although
your body needs fat you should keep track of the fat you consume and try to
have god fats instead of low bad fats.
Recreational drugs
Alcohol and Nicotine increase blood pressure
Sedentary lifestyle and lack of exercise
If you do not exercise you do not get the benefits that exercise have on the
cardiovascular system. Also lack of exercise can be linked to gaining weight as
calories are not burnt off with exercise.
Stress
On going stress in every day life has a negative affect on your cardiovascular
system as it increases resting heart rate and raises blood pressure.
Blood composition
Red blood cells
Red blood cells contain haemoglobin that is a compound of protein andiron.
Haemoglobin combines readily with oxygen to form a compound
calledoxyhaemoglobin.
It will combine with oxygen where oxygen is plentiful and yet readily lose it
where oxygen is scarce, as in the body tissue.
Red blood cells are produced in the red marrow of bones such as the sternum,
ribs and vertebrae.
White blood cells
White blood cells form a mobile guard and repair system to keep disease from
the body.
They are made in the bone marrow, the lymph nodes and the spleen.
Platelets
Platelets are tiny structures.
They produce clotting when a blood vessel is damaged.
Plasma
Plasma is a pale, straw coloured, liquid.
It is 92% water.
The remaining 8% consists of food substances.
It also maintains the correct balance of chemicals, water content and
temperature levels within the body.