Download Heart Rate (HR) x Stroke Volume (SV) = Cardiac Output

Cardiovascular System
DEFINTION: This is the system that transports blood (and nutrients) around the body. It is
made up of the heart, blood vessels and blood.
During exercise the cardiovascular system is in charge of delivering oxygen (arteries) to
the working muscles and removing carbon dioxide (veins).
- Heart Rate: The speed of the heartbeat measured by the number of contractions of the
heart per minute (bpm).
- Stroke Volume: is the amount of blood pumped out of the heart with each beat.
- Cardiac Output: is the amount of blood pumped out of the heart per minute. This is
worked out by:
Heart Rate (HR) x Stroke Volume (SV) = Cardiac Output
- Blood Pressure: The amount of force the blood applies on the sides of the blood vessels.
There are two types; systolic (pressure when blood is pumped out of the heart – the
higher number) and diastolic (pressure when the heart relaxes – the lower number).
Cardiovascular System (GCSE PE: Unit 1.2.2)
Immediate Effects of Exercise on the Cardiovascular System
These things happen as soon as the body starts exercising.
They all happen because the body needs more OXYGEN to create ENERGY for the
working muscles.
1. Increase Heart Rate: the heart beats quicker during exercise to pump more blood
(and therefore more oxygen) around the body.
2. Increased Blood Pressure: Since the heart is pumping faster there is more pressure
and force on the walls of the blood vessels.
3. Increased Cardiac Output: As heart rate increases so does the amount of blood
pumped out every minute.
Remember: Heart Rate (HR) x Stroke Volume (SV) = Cardiac Output
Cardiovascular System (GCSE PE: Unit 1.2.2)
Long Term Effects of Exercise on the Cardiovascular System
These things happen when the body has been exercising over a long period (e.g. 6 months).
1. Cardiac Hypertrophy: the heart is a muscle. If it is trained it will increase in size and strength.
BENEFIT: A large, strong heart can reduce the chance of heart disease.
2. Increased Stroke Volume: Since the heart gets bigger, more blood can be pumped out with every
beat
BENEFIT: More blood every beat means more oxygen can be pumped to the muscles.
3. Increased Maximum Cardiac Output: Since more blood can be pumped every beat (stroke
volume) the total amount of blood pumped out every minute also increases.
BENEFIT: Increased oxygen delivery.
Remember: Heart Rate (HR) x Stroke Volume (SV) = Cardiac Output
4. Decreased Resting Heart Rate: Since the heart can pump out more blood every beat it does not
have to work so hard when resting.
BENEFIT: Puts less stress on heart when resting.
Cardiovascular System (GCSE PE: Unit 1.2.2)
Long Term Effects of Exercise on the Cardiovascular System
These things happen when the body has been exercising over a long period (e.g. 6 months).
5. Increased number of Capillaries (around muscles) and more Red Blood Cells: Training leads to
the growth of more small blood vessels and red blood cells within the blood.
BENEFIT: Allows more oxygen to be carried in the blood and to be absorbed into the muscles.
6. Improved Recovery Heart Rate: Fitter people will see their working heart rate return to its resting
levels quicker.
BENEFIT: Allows a quicker recovery after exercise.
7. Decreased Blood Pressure: Since the heart does not have to work as hard when trained, the
blood pressure will drop.
BENEFIT: Reduces chances of heart attacks and allows more effective transfer of blood (and oxygen).
8. Healthy Veins & Arteries: Long periods of exercise helps to reduce the amount of cholesterol in
the blood vessels.
BENEFIT: Allows blood to flow through the vessels more easily.
Cardiovascular System (GCSE PE: Unit 1.2.2)
Lifestyle Effects on the Cardiovascular System
There are a number of different lifestyle factors that can also have an effect on the cardiovascular
system.
1. Cholesterol: Eating a diet with lots of a unhealthy fats – low density lipoproteins (LDL) - will
increase cholesterol. Cholesterol builds up in the blood vessels, causing the vessels to get narrower.
EFFECT: High cholesterol can lead to high blood pressure, strokes and heart attacks because of the
narrow blood vessels.
2. Iron: Foods that are high in iron allow oxygen to get into the red blood cells more easily.
EFFECT: This allows more oxygen to get to the working muscles and therefore gives muscles more
energy. Lack of iron can lead to anaemia.
3. Rest: When exercising it is important to allow rest days for the heart to recover and adapt.
BENEFIT: Rest allows the heart to increase in size (cardiac hypertrophy) – and therefore increases
stroke volume.
4. Lack of Exercise: Lack of exercise can cause stress on the heart (will mean blood pressure and
resting heart rate remain high).
BENEFIT: Can lead to heart disease.
Cardiovascular System (GCSE PE: Unit 1.2.2)