Health and Fitness
Health and Fitness means refearing to a persons physical wellbeing.
being healthy means being free from infection and being fit relates to how much physical activities you are able to do and how easy your body is able to recover after.
Different types of exercise develop different aspects of fitness,whitch are measurable,for exmple strength stamina flexibility agility and speed
Cardiovascular effiency-How well the heart copes with aerobic exercise and how quickly it recovers afterwards-is often used as a measure of general fitness
The Circulatory System
The Heart pumps blood around the body in blood vessels called arteries,capillaries and veins. It beats automatically but the rate varies depending on the body's level of stress and exertion.
The heart is a muscular pump. it alternately relxes to fill with blood and contracts to squeeze the blood out into the arteries, so the blood is always under pressure. this ensures that it reaches all the cells to supply them with oxygen and glucose for respiration
Equation for respiration
Glucose+Oxygen>Carbon dioxide+water energy released
Word equation for respiration
Blood pressure is a measure of the force of the blood per unit area as it flows through the arterie. blood pressure is measured in mm Hg (millimetres of mercury)
Blood pressure is at its highest when the heart muscle contracts, forcing blood into the arteries this is called the systolic blood pressure. when the heart relaxes the pressure in the arteries drops this is called the diastolic blood pressure.
Healthy blood pressure
Normal blood pressure is about 120/80mm Hg.
(120mm Hg is the systolic pressure) However, it can be affected by age and lifestyle
Regular aerobic excercise strengthens the heaer and helps maintain a normal blood pressure. A healthy diet can also help.
Long term high blood pressure and Low blood pressu
Long-term high blood pressure is dangerous
because the blood vessels can weaken and eventually burst. Burst blood vessels in the brain (called a stroke) or in the kidneys can cause permanent damage.
Low blood pressure, usally caused by weak pumping of the heart, can also be a seriouse problem. The blood does not circulate efficiently so some parts of the body are deprived of glucose and oxygen. This can lead to dizziness and fainting, and cold hands and feet
Excess weight (whitch can lead to obesity) due to a lack of exercise and a poor diet puts strain on the heart,whitch can lead to high blood pressure. Other factors that can damage the heart and blood vessels and lead to high blood pressure
- High stress level
- exess alchcol
- a diet which is high in saturated fat,sugar or salt
Effect of Exercise
As a person exercises their breathing and pulse rate increase to deliver oxygen and glucose to the cells in the muscles more quickly. This increase helps to remove carbon dioxide that is produced during respiration more quickly.
However there are limits to how much oxygen and glucose can be devlivered around the body so there is another method of respiration what is called Anaaerobic Respiration Anaerobic respiration takes place in the absence of oxygen. It quickly releases a small amount of energy through the incomplete breakdown of glucose.
Glucose-----> Latic acid=A bit of energy released
Anaerobic respiration occurs when the muscles are working so hard that the lungs and circulatory system cannot deliver enough oxygen to break down all the avaliable glucose through aerobic respiration.
At this point, anaerobic respiration starts to take place in addition to aerobic respiration. The latic acid produced during anaerobic respiration is relatively toxic to the cells and can cause pain (cramp) and a sensation of fatigue in the muscles
Recovering After Anaerobic Respiration
Latic acid produced during anaerobic respiration must be broken down fairly quickly to avoid cell damage and relieve the feeling of fatigue.
immediately after anaerobic exercise
- The heart rate stays high-pumping blood through the musckes to remove the lactic acid and transport it to the liver to be broken down
- Deep breathing continues-ensuring enough oxygen is taken in to oxidise the lactic acid (producing carbon dioxide and water)
in effect the body is taking in oxygen that is not available for anaerobic respiration during exertion. This is why the process is sometimes referred to as repaying the oxygen debt.
A Balanced Diet
A balanced diet must contain
- Carbohydrates and fats to provide energy
- protein for growth and repair of tissues (and energy if carbohydrates are in short supply)
Other substances are also needed in a balanced diet to keep us healthy, although they do not provide energy they include...
- Minerals,such as iron which is needed to make haemoglobin in the red blood cells
- Vitamins such as vitamin C,which is needed to prevent scurvy
- Fibre,whitch prevents constipation
- water which prevents dehydration