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A Healthy Lifestyle
Summary
Title of the Chapter: A healthy lifestyle
Diet đĨđ
Your lifestyle is how you live your life every day.
A healthy lifestyle is the best way to keep your body healthy and strong.
The most important things you can do are eating healthy food, exercising (moving your body), and not smoking.
In Chapter 4, you learned a lot about diet.
Diet is the food and drink you have every day.
You saw a picture (Figure 4.9) that looked like a pyramid to help you choose a balanced diet.
Everyone needs a balanced diet to grow well and be healthy.
Here are some ways that a poor diet (a diet that is not balanced) can stop humans from growing and developing well.
Malnutrition đĨ
Malnutrition means you are not eating the right kinds of food or not eating enough food.
We read about malnutrition and famine (when many people don't have enough food) in Chapter 4.
Malnutrition can happen even if you eat too much, but it usually happens in places that don't have enough food.
Deficiency diseases đŠš
When you don't eat enough of a vitamin or a mineral, you can get a deficiency disease.
Sometimes, these diseases happen in places where there is not enough food.
If you don't eat enough iron, your body can't make enough red blood cells.
This disease is called anemia (or anaemia).
People with anemia look very pale and feel tired all the time.
When there is not enough vitamin C, a disease called scurvy can happen.
When there is not enough vitamin D, a disease called rickets can happen.
You learned that vitamin D helps your body use calcium to make bones strong.
You saw on page 29 that not having enough oxygen can cause a disease.
This happens because there is not enough hemoglobin in the blood.
Hemoglobin is the part of the blood that carries oxygen.
If a person with this disease doesn't get enough oxygen, they will always feel tired.
Obesity đ
Obesity is when a child or an adult has too much body fat.
This happens when they eat a lot of sweets, foods with a lot of fat, chips, pizza, or other foods with too many carbohydrates and fat.
The person uses less energy than they take in from food, so the extra energy is stored as fat.
Having too much body fat makes a person heavier and look different from people with a normal weight.
Obesity is a serious health problem that needs special talking and treatment from a doctor.
The doctor's goal is to help the person get better completely.
Anorexia nervosa đ
Anorexia nervosa is a disease where a person doesn't eat enough food and is very scared of gaining weight.
They think they are heavier than they really are.
This disease happens more often to teenage girls and young women.
It causes the body to use up the energy stored in fat first.
Then, it uses the energy stored in protein, like the protein in muscles.
The body's energy is used up, and the person loses a lot of weight.
In the worst cases, this disease can cause death.
Treating obesity đââī¸
There are two main parts to treating obesity in children and adults.
One part is eating a balanced diet (the right kinds of food).
The second part is exercising a lot to burn the extra energy.
The goal is to help the person's body grow into the right size so that their weight and height match up as they get older.
The treatment for adults and children is a bit different.
The most important goal is for the person to lose fat and become a healthier weight.
A healthy heart â¤ī¸
Your heart is about the size of your fist and is a strong muscle.
It beats about 2.5 billion times during a person's life!
It works to pump blood all around your body.
It sends about 5 litres of blood around every minute.
The blood goes to all the small blood vessels (like tubes) in the body.
Blood vessels are like a network of tubes that carry the blood.
The heart's beat pushes the blood out of the heart and into the arteries (the largest blood vessels).
This push is called blood pressure.
When you push your finger on a drawing pin into a board, you use pressure. This is similar to the force the heart uses to pump blood around the body.
The walls of the arteries are strong and can stretch when the heart pumps the blood.
In young people, the arteries are wide open, so the blood flows easily without much pressure.
As the body gets older, the walls of the arteries become less stretchy.
The heart has its own blood vessels called the coronary arteries and veins.
These vessels bring blood to and from the heart muscle itself.
Cholesterol and the circulatory system đŠ¸
Over time, fatty things like cholesterol stick to the inside walls of the arteries.
Cholesterol is a waxy, soft substance that is part of every cell.
When this sticky plaque builds up, it makes the artery smaller.
This makes it harder for the blood to push through the artery, and the blood pressure goes up.
The artery has less space for the blood to flow through.
The blood can get sticky and form a small clot called a thrombus (many are called thrombi).
A thrombus can block the artery and stop the blood from getting to a body part.
If this happens in a coronary artery (a vessel of the heart), it stops the oxygen and nutrients from getting to the heart muscle. This causes a heart attack.
The word "coronary" is used to describe a heart attack.
Did You Know?
A thrombus (blood clot) in an artery in the brain causes a stroke.
A stroke means a part of the brain is damaged because it can't get oxygen and nutrients (food).
Science in context đ¨âđŦ
A long time ago, in the early 1900s, a Russian scientist named Nikolay Anichkov (1885-1964) was studying things that cause heart disease.
He fed rabbits a diet with lots of cholesterol and found that patches of a fatty substance formed inside their arteries.
Other scientists did not pay attention to his work because they thought it was only true for rabbits.
About 40 years later, an American scientist named John Gofman (1918-2007) started working on a similar problem: how to connect cholesterol in human blood to heart disease.
He created ways to separate the different fatty substances that carried cholesterol in the blood.
He did experiments to test his ideas and found proof that they were right.
Again, other scientists did not listen to his work, but his ideas were shown to be correct by new proof later on.
After some time, another American scientist named Ancel Keys (1904-2004) started a study that looked at heart disease in different countries.
He set up a big investigation called the Seven Countries Study.
The results of this study supported the idea that high levels of cholesterol in the blood were a cause of patches forming in the arteries and causing heart disease.
Activity and the heart đââī¸
The heart is made of muscle, just like all other muscles in the body.
It needs exercise to stay strong and healthy.
The heart muscle squeezes when you exercise, making it stronger.
Doing exercise often makes many of your organ systems (groups of organs that work together) better.
It helps you lose weight because it burns up the extra fat you've stored.
Exercise helps your body use oxygen better.
More blood is pumped to your muscles when you exercise.
The muscles need more blood to work hard.
The heart beats faster and harder during exercise than when you are resting.
This makes your body more flexible and strong and increases your endurance (how long you can keep doing an activity).
Table 5.1 Levels of fitness required for different activities.
Here is what the table says about different activities and the types of fitness they need:
Basketball needs a high level of Strength, Flexibility (being able to bend), and Endurance (stamina).
Dancing needs a medium level of Strength and high levels of Flexibility and Endurance.
Golf needs a medium level of Strength and Flexibility and a low level of Endurance.
Long-distance running needs a low level of Strength and Flexibility and a high level of Endurance.
Rugby needs high levels of Strength, Flexibility, and Endurance.
Soccer needs medium levels of Strength, Flexibility, and Endurance.
Squash needs high levels of Strength, Flexibility, and Endurance.
Swimming needs high levels of Strength, Flexibility, and Endurance.
Tennis needs a medium level of Strength and high levels of Flexibility and Endurance.
Walking needs a low level of Strength and Flexibility and a medium level of Endurance.
Care with exercise đ¤¸
When people want to get fit, they can choose activities that they like.
But sometimes people try to exercise too hard or too much when they first start.
This can cause a sprain (a stretch or tear of a strong band called a ligament) or pain in a joint (where bones meet).
It takes a long time for the body to get used to new activities.
The skeleton (bones) and muscles have to work together to move your body.
It is very important to start exercising slowly and build up the time you spend exercising.
This helps your muscles and joints get used to the movement slowly.
If someone gets hurt (an injury), they might not want to continue exercising.
But it's important to remember that the body gets stronger and fitter over time.
Smoking and health đŦ
We all need a respiratory system (lungs and airways) that works well to take in oxygen and let out carbon dioxide.
A healthy respiratory system is important for a person's good health.
The respiratory system is easily damaged by smoking.
There are over a thousand different chemicals (bad things) in cigarette smoke.
One of these chemicals is nicotine, which is highly addictive (it makes you want to keep smoking all the time).
Smoking and growth and development đļ
We have seen that smoking can hurt the lungs and affect a person's growth and how they develop.
The damage to the lungs makes them less good at taking in oxygen and giving it to the body's cells.
Pregnant women who smoke take in less oxygen, which is bad for the baby they are carrying.
This can cause the baby to be born smaller and less developed.
Adults who smoke may not feel like eating as much, so they get less food and fewer nutrients.
This can also lead to heart disease and other health problems.
Emphysema đ¨
In the air sacs of the lungs (called alveoli), the smoke causes damage to the walls.
This makes it harder for oxygen and carbon dioxide to exchange (switch places).
The alveoli burst and merge (join together) to make bigger, less helpful air sacs.
This disease is called emphysema.
It causes people to breathe faster than healthy people.
Chronic bronchitis đˇ
Chronic bronchitis is another disease caused by smoking.
In the airways of the lungs (called bronchi), the smoke causes the lining to get swollen (inflamed).
The airways make too much mucus (a sticky liquid).
The bronchi get smaller and smaller, making it hard to breathe.
It also causes a lot of coughing.
Cancer of the lung đĻ
The tiny hairs inside the airways (called cilia) move mucus and small pieces of dirt out of the lungs.
The chemicals in cigarette smoke damage these cilia, so they can't do their job well.
This means small bits of dirt and mucus stay in the throat.
The smoker tries to get the dirt and mucus out by coughing. This is the smoker's cough.
The cells lining the airways are hurt by the chemicals in the smoke.
Some of these damaged cells may change and become cancer cells.
These cells start to divide (copy themselves) very quickly and form a tumour (a lump of bad cells).
The tumour can block the airway or spread to other parts of the lung where more tumours can grow.
Helping smokers stop đ
People smoke because they become addicted (their body needs) to the nicotine in the tobacco.
Addiction is a condition where a person can't live a normal life without a substance.
Some ways to help smokers stop are by giving them something that has nicotine but not the other harmful chemicals in smoke, like nicotine patches (sticky pads) or nicotine gum.
This helps them slowly stop needing the nicotine.
Some people need special help and support to stop smoking, like from a doctor or counselor.
In some countries, smoking in public places and smoking cigarettes are not allowed.
Some research suggests that e-cigarettes (vapes) are dangerous and do not help people stop smoking.
End of chapter questions â
Here are some questions to help you remember what you learned!
1. What can happen in an artery if there is too much cholesterol in the diet?
If you eat too much cholesterol, it can stick to the inside of your arteries (the tubes that carry blood). This makes the artery smaller and harder for blood to flow.
2. What is a thrombosis?
A thrombosis is a small, sticky blood clot that can block an artery.
3. What causes a heart attack? â¤ī¸
A heart attack happens when a blood clot (thrombus) blocks an artery that goes to the heart muscle. This stops oxygen and food from getting to the heart muscle.
4. What causes a stroke?
A stroke happens when a blood clot (thrombus) blocks an artery that goes to the brain. This stops oxygen and food from getting to a part of the brain.
5. What should you include in your diet to stop you getting a high level of cholesterol?
You should eat foods that are good for you, like fresh fruits and vegetables, and foods that are low in fat.
6. What disease could you develop if your diet lacks vitamin C?
You could get a disease called scurvy.
7. How does smoking affect the lungs?
a. It can cause diseases like chronic bronchitis and emphysema.
b. It can also cause lung cancer.
c. It causes damage to the tiny hairs (cilia) in the lungs.
d. It stops the lungs from working well to get oxygen and get rid of carbon dioxide.
8. Your teacher will put an inquiry question on the board. You will need a stopwatch or timer. Use your pulse to measure your heartbeats per minute (bpm).
Plan, investigation and recording data:
1. Hold out your right hand with the palm facing up.
2. Put the thumb of your left hand under your right wrist.
3. Put the first two fingers of your left hand on your wrist.
4. Feel around on your wrist with these two fingers to find a throbbing artery (this is your pulse).
5. You can measure your pulse rate by counting how many times your pulse beats in one minute.
Here is a reminder: You learned how to measure your pulse rate last year.
Some people count the beats for 15 seconds, then multiply the number by 4 to find the beats per minute. This helps you be more exact.
The teacher will ask you to:
1. Plan a way to write down your results.
2. Take your pulse while sitting down for 1 minute and record the beats per minute.
3. Take your pulse for 15 seconds, then multiply the number of beats by 4 and record the beats per minute.
4. Make a plan for someone else to take your pulse to check your results. If your teacher says it's okay, try it!
Examining the results:
1. Compare the numbers you got from your own measurements and from the measurements of someone else.
Conclusion:
1. Write a conclusion (what you found out). Which way of measuring is the most exact, or are they both the same?
2. Is your conclusion limited in some way? Explain your answer.
3. What things could be done better? Explain the changes that you suggest.
a. Anwari, Baylee, Chumbo, and Daisy used their pulse to test their heart rate monitor results.
b. They checked their pulse rate when resting, 1 minute after exercise, 2 minutes after exercise, and 3 minutes after exercise.
c. Here are their results (beats per minute):
Anwari: 71 when resting, 110 after 1 min, 90 after 2 min, 79 after 3 min.
Baylee: 74 when resting, 115 after 1 min, 88 after 2 min, 77 after 3 min.
Chumbo: 80 when resting, 107 after 1 min, 98 after 2 min, 87 after 3 min.
Daisy: 69 when resting, 80 after 1 min, 77 after 2 min, 72 after 3 min.
d. The teacher will ask you to:
1. Make a table of the results.
2. Make a graph of the results.
3. What pattern can you see in the results?
4. When did Anwari and Baylee's hearts beat at the same speed?
5. Anwari says he is healthier than Chumbo. Do you think the results show he is right? Explain your answer.
6. Which result does not follow the pattern (the trend)? Explain why this may be so.
Challenge Yourself đĒ
Heart health:
Having a healthy heart means it takes you less time to return to your resting heartbeat (your normal one) after running.
Plan an investigation to find your normal heartbeat and your heartbeat 2 minutes after running for 2 minutes.
Plan this with your friends and your teacher!
Cholesterol levels:
Scientists are still studying the links between diet and diseases.
Use the internet to find out the newest advice about healthy cholesterol levels.
Use the websites and information that your teacher suggests.
How do the things you find compare with the results of studies from a long time ago?
Smoking survey:
9. A survey (a set of questions) was made to find out about the smoking habits of young people aged 20 to 25.
For each year group, 1000 men and 1000 women were asked if they were occasional smokers (smoke sometimes) or regular smokers (smoke often).
The results for four of the age groups are shown here:
Table 5.2 Smokers
Age 21: 10 women were occasional smokers; 15 women were regular smokers.
Age 21: 10 men were occasional smokers; 20 men were regular smokers.
Age 22: 35 women were occasional smokers; 0 women were regular smokers.
Age 22: 30 men were occasional smokers; 40 men were regular smokers.
Age 23: 70 women were occasional smokers; 90 women were regular smokers.
Age 23: 60 men were occasional smokers; 70 men were regular smokers.
Age 24: 160 women were occasional smokers; 110 women were regular smokers.
Age 24: 140 men were occasional smokers; 80 men were regular smokers.
a. How is the information for occasional and regular smokers for men similar?
b. Where is there a result that is very different from the others (an anomalous result)? Give a reason why it might be that way.
c. What is the difference in the number of regular smokers between men and women at the age of 24?
d. What is the percentage of the men aged 24 who are regular smokers? (Remember: 80 out of 1000).
e. Do you think the percentage of men and women who are regular smokers will go up, stay the same, or go down for men and women aged 25?
f. In which group, men or women, do you think will have more occasional smokers at the age of 25?
Summary â¨
One part of a healthy lifestyle is having a balanced diet.
An unbalanced diet can lead to malnutrition (not enough food or bad food), deficiency diseases (missing vitamins), anorexia nervosa, or obesity (too much fat).
A healthy heart is very important for a healthy lifestyle.
Poor blood pressure or high cholesterol can lead to problems with the heart, such as blood clots, thrombosis, or a stroke.
Regular exercise makes many of the organs (like the heart and lungs) work better. It also makes you less likely to get hurt or sick.
Smoking is bad for health, growth, and development and can cause sicknesses such as cancer, emphysema (bad lungs) and 'smoker's cough'.
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