Factors affecting the heart

How does exercise affect the heart?

Exercise increases the heart rate:

• Muscles require more oxygen for aerobic respiration.

• That oxygen is supplied by the bloodstream.

• The flow of blood is determined by the heart rate

Exercise also increases stroke volume:

• Stroke volume is the volume of blood pumped in one heartbeat.

• A more powerful contraction in the heart causes more blood to be pumped every ‘stroke’.

How to measure heart rate

Heart rate can be estimated by measuring pulse rate.

• The heartbeat will cause the walls of arteries to ‘pulse’ at the same rate.

• A pulse is usually taken by holding two fingers to the neck or the wrist

How to measure the change in heart rate after excersise

• Take a resting pulse for 1 minute.

• Run for 2 minutes at maximum effort.

• Take pulse again

Adrenaline

Adrenaline is a hormone that is released during exercise or stress.

• Adrenaline is responsible for the ‘fight or flight’ response.

• Adrenaline increases both heart rate and stroke volume.

• More oxygen is supplied to tissues for respiration.

• More energy is released.

Blood is also redirected from other organs.

• Blood is diverted from the digestive system during periods of intense exercise.
  

Cause of coronary heart disease (CHD)

• Fatty substances including cholesterol can deposit on the walls of the coronary arteries.

• This plaque can cut off the blood supply to the cardiac muscle.

Symptoms of coronary heart disease

• Chest pain

• Shortness of breath

What can CHD cause

Heart attacks

Where does CHD occur

The coronary arteries in the heart

Diagram for coronary heart desease

Risk factors of CHD (4)

• Genetics

• Diet

• Stress

• Smoking

Explanation for genetics as a risk factors of CHD

Many people have a genetic predisposition to CHD

Explanation for diet as a risk factors of CHD

Poor diet can lead to high cholesterol which is a major risk factor for CHD

Explanation for stress as a risk factors of CHD

When stressed blood pressure inceases causing damage to the walls of arteries.

Explanation for smoking as a risk factors of CHD

Nicotine increases blood pressure and increases the likelihood of blood clots.