One healthy lifestyle practice is to have regular scheduled medical check-ups, and we can also measure the parameters of our body health ourselves if we know the correct technique p. 33. This chapter covers four of them: body temperature, pulse rate, blood pressure and Body Mass Index (BMI) p. 33.
3.1 Body Temperature
Temperature is a measurement of the degree of hotness and coldness of a substance, and body temperature is the measurement of the degree of hotness and coldness of our body p. 34. Any change in body temperature, whether it is higher or lower, is a sign that our body has a health problem p. 34. The skin and the endocrine system are important to regulate body temperature p. 34.
Body temperature is measured by using a thermometer, and there are four types of thermometers p. 34. The clinical thermometer measures body temperature in the range of 35°C to 42°C, while the laboratory thermometer measures the temperature of liquids in the range of -10°C to 110°C p. 34. The rectal thermometer measures body temperature through the rectum, and the infrared thermometer measures it without having any contact with the body p. 34.
Clinical thermometer. Before using it, make sure its temperature is lower than 35°C; if it exceeds 35°C, shake the thermometer until the reading is lower than 35°C p. 35. Place it under the armpit or in the mouth for about 2 to 3 minutes, or until a ‘beep’ sound is heard on a digital clinical thermometer, then pull it out and record the reading p. 35. The kink in the clinical thermometer ensures that the mercury does not go down quickly after it is removed from the mouth or the armpit, which gives a more accurate reading p. 35.
Laboratory thermometer. It is not suitable to measure body temperature because it does not have a kink in the mercury tube, so the reading goes down quickly once it is removed from the body p. 35. If it is used, the reading must be taken while the thermometer is still in the mouth or under the armpit p. 35. The clinical thermometer can measure temperature with an accuracy of 0.1°C, whereas the laboratory thermometer has an accuracy of 1°C p. 35.
Rectal thermometer. It is usually used for infants less than 3 months old, and it must be labelled for rectal use p. 35. Clean the tip with alcohol, dab some petroleum jelly on it, raise the infant’s legs and insert 1.5 – 2.5 cm of the thermometer into the infant’s rectum until a ‘beep’ sound is heard, then record the temperature p. 35.
Infrared thermometer. It can be used without any contact with the individual: aim it on the forehead at a distance of about 5 cm, never directly or indirectly at the eyes, and record the temperature p. 36. Taking temperature with this thermometer is very quick p. 36.
A normal human body temperature is 36.9°C, and an increase or decrease of this temperature shows that the body is not in a healthy condition p. 36. Body temperature can rise above normal because of infection by bacteria or a virus, exposure to extreme heat such as heat stroke or extreme sunburn, or vigorous exercise p. 36. When your body temperature is above 37°C, you may be having a fever p. 36. Body temperature also goes below normal if you are exposed to extreme cold, and this condition can also lead to death p. 36. Homeostasis is the mechanism that regulates body temperature so that it remains in a balanced and stable state p. 36.
Figure 3.1 Types of thermometers
p. 34| Thermometer | What it measures | Range |
|---|---|---|
| Clinical | Body temperature | 35°C to 42°C |
| Laboratory | The temperature of liquids | -10°C to 110°C |
| Rectal | Body temperature through the rectum | – |
| Infrared | Body temperature without any contact with the body | – |
Using a clinical thermometer
p. 35- 1 Check the reading It must be lower than 35°C; if not, shake the thermometer until it is
- 2 Place it Under the armpit or in the mouth for about 2 to 3 minutes, or until the digital one beeps
- 3 Pull out and record The kink stops the mercury going down quickly, so the reading stays accurate
Figure 3.4 Factors that can cause body temperature to be above normal reading
p. 36- Bacteria
- Virus
- Heat stroke
- Extreme sunburn
- Vigorous exercise
Quiz 3.1 Finished 3.1? Next is 3.2 Pulse Rate →
3.2 Pulse Rate
Pulse rate is the measurement of the number of heartbeats per minute (bpm) p. 37. The pulse can be felt at pulse points, areas where the arteries are located very close to the surface of the skin; when the heart beats, the pulse is sent to these arteries and can be felt through the skin p. 37. Doctors usually take the pulse at the wrist because it is clear, prominent and easy p. 37.
Experiment 3.1 tests how gender, age and physical activity affect the pulse rate, using a stopwatch and counting the pulse for 1 minute p. 38. Its hypotheses are that females have a higher pulse rate compared to males, and that the older a person is, the lower his pulse rate p. 38. For physical activity, the hypothesis is that the more vigorous the physical activity, the higher the pulse rate p. 39. In that part, a student rests, walks and runs, each for two minutes, and rests for 5 minutes before the next activity p. 39. Activity 3.1 then gathers information on how the pulse rate relates to health level, fitness level, emotions and stress p. 40.
Experiments and activities
Experiment 3.1A: Human pulse rate based on genderp. 38
Aim: To study the effect of gender on the human pulse rate.
- Manipulated variable
- Gender
- Responding variable
- Pulse rate
- Constant variable
- Time period, age and type of physical activity
- Hypothesis: females have higher pulse rate compared to males.
- Work in pairs: count the pulse of the male students for 1 minute while a partner keeps the time with a stopwatch.
- Record the pulse count in 1 minute, then repeat for the female students.
Experiments and activities
Experiment 3.1B: Human pulse rate based on agep. 38
Aim: To study the effect of age on the human pulse rate.
- Manipulated variable
- Age
- Responding variable
- Pulse rate
- Constant variable
- Time period, gender and type of physical activity
- Hypothesis: the older a person is, the lower his pulse rate.
- Count the pulse of a student for 1 minute while another student keeps the time.
- Repeat with your teacher and the laboratory assistant, of the same gender as the student.
Experiments and activities
Experiment 3.1C: Human pulse rate based on physical activityp. 39
Aim: To study the effect of physical activity on the human pulse rate.
- Manipulated variable
- Type of physical activity
- Responding variable
- Pulse rate
- Constant variable
- Time period, age and gender
- Hypothesis: the more vigorous the physical activity, the higher the pulse rate.
- A student rests, walks and runs, each for two minutes, resting for 5 minutes before the next activity.
- Count the pulse for 1 minute after each activity and record it in a table.
Quiz 3.2 Finished 3.2? Next is 3.3 Blood Pressure →
3.3 Blood Pressure
Blood pressure is the pressure applied by the blood on the walls of the blood vessels during blood circulation p. 41. It is measured by using a sphygmomanometer, and its unit is millimetres of mercury, with the symbol mmHg p. 41. Medical practitioners in hospitals and clinics use the sphygmomanometer along with the stethoscope, while blood pressure can be monitored at home with a digital sphygmomanometer p. 41.
Blood pressure is measured by taking two readings p. 41. The top number is the systolic pressure, the pressure applied on the wall of blood vessels when the heart muscles contract p. 41. The bottom number is the diastolic pressure, applied when the heart muscle is resting between heartbeats p. 41. Both are stated in mmHg because mercury was used in the first accurate pressure gauges and is still the standard unit of measurement for pressure in medicine p. 41. The measurement is recorded as systolic/diastolic, for example 120/80 mmHg p. 41.
Readings that are high and prolonged show that you might be experiencing high blood pressure, while readings that are low and prolonged show that you might be experiencing low blood pressure p. 42. Table 3.1 classifies adult readings, from optimal (less than 120 / less than 80 mmHg) to high blood pressure stage 3 (180 and above / 110 and above mmHg) p. 42. High blood pressure does not usually have any clear symptoms, and if it is not well-controlled it can lead to more serious problems such as stroke p. 42. The best way to track this problem is by having regular medical check-ups p. 42.
Table 3.1 Classification of blood pressure readings for adults
p. 42| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Optimal | Less than 120 | Less than 80 |
| Normal | 120 – 129 | 80 – 84 |
| At risk | 130 – 139 | 85 – 89 |
| High blood pressure stage 1 | 140 – 159 | 90 – 99 |
| High blood pressure stage 2 | 160 – 179 | 100 – 109 |
| High blood pressure stage 3 | 180 and above | 110 and above |
Quiz 3.3 Finished 3.3? Next is 3.4 Body Mass Index (BMI) →
3.4 Body Mass Index (BMI)
Body Mass Index, commonly known as BMI, is the measurement of body mass against height p. 43. It is calculated as body mass in kg divided by the square of the height in m², and BMI is a way to determine whether we have a body mass problem or not p. 43. Table 3.2 classifies a BMI below 18.5 as underweight, 18.5 – 24.9 as desirable weight, 25.0 – 29.9 as overweight and 30.0 or more as obese p. 43. Studies show that a person with an ideal BMI of 18.5 – 24.9 kg m⁻² has a longer lifespan than a person with a lower or higher BMI p. 43.
Being overweight increases the risk of serious illnesses such as heart attack, high blood pressure, stroke, diabetes mellitus and complications of joints and bones p. 44. Being underweight can also increase the risk of heart diseases, a decrease in the body’s defence against diseases, fatigue, anaemia and depression p. 44. Achieving and maintaining an ideal body weight through a healthy diet and consistent physical activities can prevent these illnesses p. 44. To decrease body mass, set a realistic goal such as reducing half a kilogram of mass weekly, and do moderate exercises such as brisk walking, cycling and swimming for at least 30 minutes, three times a week p. 44.
Table 3.2 Body Mass Index chart
p. 43| BMI (kg m⁻²) | Category |
|---|---|
| Less than 18.5 | Underweight |
| 18.5 – 24.9 | Desirable weight |
| 25.0 – 29.9 | Overweight |
| 30.0 or more | Obese |
Changing body mass in a healthy way
p. 44Ways to increase body mass
- Healthy, balanced diet based on the Malaysian food pyramid and the Malaysian Healthy Plate
- Eat at fixed times
- Snacks packed with nutrients to increase calories
- Eat more nutritious food
Ways to decrease body mass
- A realistic goal such as reducing half a kilogram of mass weekly
- Monitor and record your body mass once a week
- Reduce or avoid food with high sugar or fat content
- Moderate exercise for at least 30 minutes, three times a week
Quiz 3.4 Finished the chapter? Test yourself with the chapter quiz.Test yourself