1          What is health and technology?

The meaning of health

There are three sides to health. This is called the health triangle.

• Social
• Mental
• Physical

If any one of these is not right then you will feel unhealthy.

Healthy Lifestyles

A healthy lifestyle would include:

• eating an appropriate range of foods
• taking regular exercise
• taking part in pleasurable activities
• taking regular relaxation
• avoiding unnecessary health risks such as smoking cigarettes, drinking alcohol and taking drugs.

Physiological measurements as indicators of health

Taking certain physiological measurements can give an indication of the health of the person.
Some measurements would include:

temperature body fat

blood pressure heart (pulse) rate

 

These measurements can be taken using high tech and low tech approaches.

Physiological Measurement	High tech approach	Low tech approach
Temperature	Thermocouple Or thermister	Thermometer
Body fat	Digital body fat sensor	Skin fold calipers
Blood pressure		Stethoscope and mercury manometer
Heart (pulse)rate	Pulsometer Heart rate monitor

Comparison of high tech and low tech measurements

 

Physiological Measurement	Advantage	Disadvantage
High tech approach	Increased accuracy	Not widely available
Low tech approach	In expensive Easy to use Widely available	Less accurate

 

2.         A Healthy Heart

The heart and circulatory system

• Students must know how to take a pulse rate measurement using a stopwatch and pulsometer.

 

The heart is made of muscle and pumps blood around the body. When the heart muscle contracts it pumps blood through vessels around the body. There are valves in your heart that make sure that the blood always flows in the right direction. It is the closing of these valves that gives the sound of the heart beat which can be heard when using a stethoscope.

Diagram of a human heart

There are three kinds of blood vessels: arteries, capillaries and veins. Arteries carry blood away from the heart, they divide again and again and eventually form very tiny blood vessels called capillaries. Capillaries allow nutrients and oxygen to pass from the blood to the tissues and allow carbon dioxide and other wastes to leave tissues. The capillaries join up with one another to form large vessels called veins. Veins return blood to the heart.

Diagrams of artery, capillary and vein

 

from heart

ARTERY

CAPILLARY

VEIN

To heart

 

 

 

Diagram showing blood flow around the body

Pulse rate as a health indicator

Each time the heart beats it pushes blood into our arteries and make them swell out a little. The pressure wave is transmitted to all parts of the body and can be detected as a pulse.

Pulse rates are expressed as beats per minute and give a direct measure of the speed at which your heart is beating. The pulse can be measured using a pulsometer or heart rate monitor.

We can find out how fit we are by measuring our resting pulse rate. This value gives a measure of the efficiency of the heart and circulation.

Normal range of pulse rate is between 60 - 70 beats per minute.

A high resting pulse rate means that your heart is having to work hard just to circulate blood around the body and can lead to heart disease.

A low resting pulse rate and a short recovery time (i.e. the time for the pulse rate to return to normal after exercise) can indicate fitness.

The resting pulse rate can be reduced by taking regular exercise.

Blood pressure under different conditions

Blood pressure is the pressure of our blood in our arteries. This pressure is caused by the pumping action of the heart.

Blood pressure can be measured using a sphygmomanometer.

Our blood pressure changes significantly depending on our emotional and physical condition, where the arm is placed during the measurement and how and where the cuff is fastened.
Blood pressure is taken as two readings:

• the first, higher pressure, is caused when the heart contracts and is pushing blood into the arteries.
• the second, lower pressure, is caused when the heart relaxes and is refilling with blood.

 

The blood pressure readings are measured in millimetres of mercury (mmHg).

A typical blood pressure of 110 (first reading), 75 (second reading) is written as 110/75.
Any reading up to 140/90 is considered to be within the normal range.

High blood pressure can be caused by a number of factors:

• overweight — being overweight puts more strain on the heart which has to work harder
• lack of exercise
• incorrect diet - too much fat and salt in food
• drinking excessive amounts of alcohol
• stress
• smoking — the heart has to work harder because carbon monoxide restricts oxygen carrying

capacity of red blood cells and nicotine narrows blood vessels

High blood pressure increases with age and can lead to a heart attack or stroke.

Low blood pressure is uncommon but can lead to fainting or can indicate heart failure.

 

Blood tests and blood counts

Often it is possible to analyse our blood to give us an indication of the state of our health. This analysis will also be able detect and monitor various illness.
Blood tests and cell counts can be used to detect:

• anaemia - iron content and red blood cell numbers are low. Common symptoms are tiredness and a pale complexion.
• infection - the presence of microbes, antibodies in the blood and an increased white blood cell count
• leukaemia - the number of white blood cells is either abnormally high or low
• diabetes - the sugar content of the blood is too high and sugar is present in the urine.
• blood groups - types of red blood cells (A, B, AB, 0).

 

3.         Healthy Lungs

The lungs and breathing

Our lungs are found inside our rib cage and they are situated on either side of the heart. The lungs are spongy pink in colour and are made up of millions of air sacs. The lungs take in oxygen into the blood and remove carbon dioxide from the blood to the air.

Exercise improves the efficiency of gas exchange in the lungs. A fit person’s breathing rate will be slower than that of an unfit person. A fit person will also have a shorter recovery time i.e. it will take less time for their breathing rate to return to normal after exercise than it will for an unfit person.

Diagram of the human respiratory system

 

The physiological measurements of the lungs

The measurement of vital capacity, tidal volume and peak flow allow us to measure the state of the health of our lungs.

Vital capacity

The vital capacity is the maximum volume of air we can breathe out after we have taken a deep breath. The vital capacity of a 16-year-old female is about 2800cm3 and for a 16-year old male it is about 4000cm3.

Tidal volume

The tidal volume is the normal volume of air breathed in or out from our lungs. This is usually about one tenth of the normal vital capacity.

Peak flow

The peak flow is a measure of the maximum rate at which air can be forced from the lungs. The peak flow rate can be used as a measurement of health e.g. it can be used in the diagnosis and management of asthma.

 

The vital capacity, tidal volume and peak flow of a person depends on the age, sex, size and
fitness of the person e.g.

• Age - vital capacity reaches a maximum by the age of 20
• Sex - females have lower vital capacities than males
• Size - the taller you are the greater your vital capacity
• Fitness - endurance training gradually increases your vital capacity

 

Health risks and effects of smoking

Smoking increases the risk of cancer and heart disease.
Carbon monoxide is a poisonous gas found in cigarette smoke. This gas reduces the oxygen carrying capacity of the blood.

4. A Healthy Body

The importance of diet and energy balance

The food and drink we eat everyday makes up our diet.
A healthy diet contains a balance of all the important nutrients:

• carbohydrates
• proteins
• fats
• vitamins and minerals
• fibres
• water.

 

Energy giving nutrients are:

• carbohydrates found in food like cereal, bread, potato
• fats found in butter, margarine and bacon.

Body building nutrients are:

• proteins found in fish, meat and peanuts.

Protective nutrients are:

• vitamins and minerals found in fresh fruit and vegetables.

About half the population in Britain are overweight and about one-fifth of them are obese. Someone who is obese is more likely to suffer from diseases such as coronary heart disease or diabetes.

There are many reasons why people are overweight but scientists are convinced that a person’s diet or eating habits is one of the many factors which determines a person’s weight.

The relationship between fat and health

The amount of body fat you have can indicate the health of a person.

Being overweight can lead to an increased risk of:

• heart disease — fat can narrow the arteries and cause an increase in blood pressure and heart attacks
• kidney failure
• arthritis
• diabetes.

Being underweight can indicate illnesses such as:

• cancer
• anorexia.

 

Body fat can be measured using calipers.

 

A skinfold caliper is a device which measures the thickness of a fold of skin with its underlying layer of fat. By doing this at key locations; shown by research to be representative of the total amount of fat on the body, it is possible to estimate the total percentage body fat of a person.

The body should have about 20% fat.

The normal ranges of body fat are shown in the table below.

Age Range (years)	Ideal % Body Fat
	Females	Males
up to 30	14-21	9-15
30-50	15-23	11-17
over 50	16-25	12-19

The relationship between body temperature and health

Students must know how to measure temperature.

 

Our body temperature needs to be kept at a constant temperature between 36.0 — 37.0°C. Our body temperature can alter slightly depending on where it is measured, the time and day and in women, the time of the month (menstrual cycle).

A body temperature above 40°C can lead to heatstroke or indicate fever as a result of fighting infection.

A body temperature below 35°C indicates hypothermia. If the temperature of the body falls below 30°C, death can result. Babies and the elderly are particularly at risk.

Exercise and the health of muscles

Most of the energy obtained from food is used for movement. AU movement is brought about by the action of muscles.

Muscles can only contract.  When they contract the parts of the body which they are attached to move. After contraction, muscles relax and return to their original shape. Muscles must work in pairs.

Diagram of muscle pairs in the arm:

Muscle strength and endurance are good ways of measuring someone’s physical fitness, but not necessarily their general state of health.

The size, strength, and efficiency of muscles can be improved through regular exercise. Muscles respond to regular exercise by growing larger and developing a better blood supply.

One way to improve the strength of our muscles is to exercise them regularly.

Muscle mass decreases if muscles are not exercised regularly. Muscle fatigue (tiredness) can be relieved by relaxation.

Reaction time as an indicator of health

Reaction time is the time taken for a person to respond to a certain stimulus.

Reaction time is a good indicator of health.

It can be measured using a dropped ruler or electronic timer.

A slow reaction time can indicate diabetes, brain or nervous disorders or arterial disease.

Our reaction time can be affected by:

• drugs — slows down reaction time
• alcohol — slows down reaction time
• excitement — speeds up reaction time

Health risks and the effects of alcohol

The effects of drinking small amounts of alcohol occasionally are short term and will not harm your body. However, alcohol is a depressant drug, and small amounts can slow down processes in your brain.

• In the short term, alcohol in the blood leads to:
• slower reaction time (increase in time taken to react)
• poor muscle control
• poor judgement.

 

In the long term, drinking alcohol can cause:

• liver damage
• brain damage.