What is aerobic exercise?
Aerobics is a gym class, set to music and led by a qualified instructor who will lead you through a variety of structured movements that will raise your heart rate and get blood and oxygen flowing more quickly around your body. Aerobics classes will often include some anaerobic exercises as well.
What is aerobics good for?
A good aerobics class will benefit your body in many ways. A regular workout will:
* strengthen your heart muscle and lungs by making them work harder; with regular exercise, you can lower your blood pressure and cholesterol
* stimulate the circulation of blood and lymph around your body, and so help strengthen your immune system
* help you burn calories and reduce your body fat
* raise your serotonin levels, stimulate your brain to release endorphins and so give you a natural "high" and easing any stress or anxiety
* increase your body strength so you are less prone to injury
* improve the shape and tone of your body.
Before you go
The important thing when you undertake any exercise class is that you choose the right one for your level of fitness. You'll usually find that aerobics classes are offered at beginner, intermediate and advanced levels.
Fitting aerobics into your day: you can timetable aerobics into your day without taking any special precautions; you can go straight back to work afterwards. Just leave yourself time to have a shower as you'll sweat a lot in the class and you'll probably find you want to wash your hair. Your make-up could take some punishment, too, so it's a good idea to take it off beforehand and allow your skin to breathe, and reapply if you want to when you leave.
What to wear: you should wear clothes that allow your skin to breathe, and you to move freely. We've all seen Jane Fonda's lycra body stockings but for us mere mortals, leggings, light tracksuit trousers and a t-shirt will be just as good. Trainers with sweat-absorbing socks are a good idea, too.
How long is it? An aerobics class usually lasts about 45 minutes to one hour.
Precautions
You should not do aerobics if:
* you have a history of heart or respiratory problems
* you have problems with your joints
* you have recently had surgery, or are prone to or recovering from injury.
You should consult your doctor if:
* you have any other medical condition, or are receiving treatment of any kind.
If you are, or think you might be pregnant, you should stick to low-impact aerobics, and can probably find a class specially for mums-to-be. A specially trained instructor will make sure you only do exercises that are appropriate.
If you feel any pain during a class or are unhappy with something you're being asked to do, for any reason, stop.
What to expect at an aerobics class
Aerobics includes a range of movements and exercises that will work on all areas of your body, from gentle jogging on the spot to star jumps, lunges, twists, stretches and tummy crunches.
A good aerobics instructor will take you through different levels of movement. You'll start with gentle low-intensity warm-up exercises including stretches as well as some light jogging, and stepping. You'll be taken gradually up to high-intensity exercises that will really help you burn calories. You will get quite out of breath and will feel your heart working.
Your instructor should then take you back down "through the gears" to gradually lower your heart rate. Borrowing something of yoga, these days some classes include a few minutes of rest or guided meditation to relax and calm you before you leave.
Be prepared for some potentially quite complicated routines and sets; some instructors may also use a lot of jargon to describe movements that you aren't familiar with. If you're not careful, you could end up with someone "grapevining" into you as you are standing there looking for the vegetation. Try not to get self-conscious if you're not doing everything in time, kicking as high, or squatting when you should be diamond-stepping. You'll soon get used to it, and you may as well try to find it hilarious getting it wrong in the meantime. Think of your serotonin levels.
Different kinds of aerobics
Apart from different classes for different levels of fitness, you can also do different kinds of aerobics classes, so you choose the one that appeals to, and suits you best!
High-impact aerobics: High-impact aerobics is a very energetic form of exercise which features lots of movements that lift you off the ground: jumping, hopping and jogging. High impact aerobics is not for the faint-hearted. It is very vigorous. It's probably a class to graduate to rather than start with as you need to be quite fit to do it. It can also be hard on your joints, so this is not a good class for anyone with weaker joints. Because it's so energetic, a high-impact class will make your body release endorphins and serotonin, which will make you feel really refreshed, energised and happy afterwards! And you'll sleep well, too. All of which can't be bad.
Low-impact aerobics: Low-impact aerobics focuses on floor-based exercises, stretches and movements, all of which involve you keeping at least one foot on the floor at all times! Whilst still giving you a good aerobic workout, a low-impact class is a more sedate form of aerobics and doesn't put so much pressure on your joints.
Because it is less vigorous, low-impact aerobics is especially good for:
* pregnant women
* older people
* anyone who is overweight
* people who have weaker joints or frailties of other kinds who are not suited to high-impact aerobic exercises
* people recovering from injury.
Low-impact aerobics for pregnant women: Aerobic exercise strengthens your heart and lungs and helps maintain muscle tone. As long as you choose exercises that are low impact - meaning no high kicks and leaps, and keeping one foot on the ground at all times to minimise stress on your joints - you should be able to continue your routine throughout most of your pregnancy.
Although you could stay fit at home with the help of an exercise video, an aerobics class designed for mums-to-be is your best bet. You'll enjoy the company of other pregnant women, and the expertise of an instructor who understands how to keep you and your baby safe. Many community recreation centres offer antenatal exercise classes. If you're already signed up for a regular aerobics class, let your instructor know that you're pregnant; she can suggest ways to modify movements that may be unsafe or too strenuous for you.
You might also enjoy yoga, particularly in the later stages of your pregnancy; these classes also offer breathing techniques that you can use during labour.
Body conditioning: A body conditioning class focuses on intensive, but low-impact exercises which tone, shape and strengthen muscles. Classes may also include some light, high-repetition weight training. Body conditioning classes often focus on particular areas such as "bums and tums".
"Kickfit" or kick-aerobics: A variation on high-impact aerobics, a kick aerobics class incorporates martial-arts style kicking and other movements to the exercise-routines, but it is non-contact. The class may also include some body conditioning.
Step aerobics: Step aerobics combines low-impact and body-conditioning exercises with a raised platform or "step" to accelerate and intensify the workout to your lower body. Step aerobics is particularly beneficial for developing and strengthening the muscles in your legs, spine and hips, and also works on your co-ordination.
A recent survey has shown that step aerobics is particularly good for strengthening bones.
Spas should provide any equipment you need for an exercise class. This includes a step. Some are bigger than others; the platform height increases with your fitness and ambition!
All stages of the class - from warm up to cool down - are likely to involve the step. Your instructor will show you the right and wrong ways to use it; the "right way" includes, for example, always stepping heel-toe when going onto or off the step, and keeping your back straight.
Be prepared for the fact that the step takes a bit of getting used to. At first, it can feel a bit like rubbing your tummy and patting your head simultaneously but stick with it. Step aerobics can be pretty tough and you can "feel it working" (we're sure you know what we mean), and you should feel results quite quickly.
Dance aerobics: Dance aerobics is a mixed-impact aerobics class with a dance slant - from jazzercise to aeropop and even hiphopics (really). This is a great way to have fun and shape up at the same time.
The movements and exercises in aerobic dance classes will depend a lot on the kind of dance that has inspired it - maybe more ballet, bellydancing or bhangra. Having said this, the exercises will be dance variations on the aerobics theme, rather than the other way around. The class will involve a similar ratio of warm up, high-intensity and cool-down exercises as other classes.
Body pump: Body pump is one of a range of branded classes that are run in exactly the same way, and involve the same exercises across the UK, and in gyms across the world.
Afterwards
After a good aerobics class, you should feel energised (if a bit tired out). Don't let that lovely natural high distract you from the fact that you will also have done a lot of sweating; make sure you allow yourself time to have a shower, or go for a swim afterwards.
If you haven't done the class before you might find you're a bit achey a few days later. This is just because your body has worked some dormant muscles and it should ease off. Definition of Aerobics:
Using the same large muscle group, rhythmically, for a period of 15 to 20 minutes or longer while maintaining 60-80% of your maximum heart rate.
Think of aerobic activity as being long in duration yet low in intensity. Aerobic activities include: walking, biking, jogging, swimming, aerobic classes and cross-country skiing. Anaerobic activity is short in duration and high in intensity. Anaerobic activities include: racquetball, downhill skiing, weight lifting, sprinting, softball, soccer and football.
Aerobic means with air or oxygen. You should be able to carry on a short conversation while doing aerobic exercise. If you are gasping for air while talking, you are probably working anaerobically. When you work anaerobically, you will tire faster and are more likely to experience sore muscles after exercise is over.
Cardiovascular Benefits
Aerobic exercise conditions the heart and lungs by increasing the oxygen available to the body and by enabling the heart to use oxygen more efficiently. Exercise alone cannot prevent or cure heart disease. It is only one factor in a total program of risk reduction; examples of other factors are high blood pressure, cigarette smoking and high cholesterol level.
Additional Benefits of Aerobic Exercise
In addition to cardiovascular benefits, other benefits of aerobic exercise include:
- Control of body fat. (Aerobic exercise in conjunction with strength training and a proper diet will reduce body fat.)
- Increased resistance to fatigue and extra energy.
- Toned muscles and increased lean body mass.
- Decreased tension and aid in sleeping.
- Increased general stamina.
- Psychological benefits - exercise improves mood, reduces depression and anxiety.
Avoid the Aerobic Curve.
The aerobic curve occurs when you begin exercising, increase your intensity level, hit the high point and gradually decrease your intensity level. The goal when exercising aerobically is to hit your target heart rate and maintain it for the entire exercise session. This works the heart muscle more effectively and burns more calories. Think of riding a bike, running or swimming - you start, hit your pace (or target zone), then you maintain your pace until the cool down. As your heart becomes conditioned, you will have to work harder to reach the target zone. Less conditioned athletes will reach their target zones quickly because their heart muscle isn't used to the workload.
Aerobic Classes (step, hi/low, slide, interval etc...)
In an aerobic class, you can do moves in low intensity or high intensity. The level of intensity depends upon how high you bring your arms (not whether the class is low impact or high impact). Aerobic instructors should show class members how to do moves in high or low intensity. Participants should choose their own level of intensity dependent upon their level of fitness and how frequently they exercise.
If you are too tired to continue exercising in an aerobic class, march in place for a while until you can resume exercising. IT IS NOT OK to stop in the middle of an aerobic class because your body is sending extra blood to the muscles. Stopping suddenly can lead to muscle cramping and dizziness (this is why all aerobic classes have a cool down at the end of the aerobic section).
Exercise Frequency
Cardiovascular fitness is an ongoing process and requires consistent reinforcement. To maintain your current level of fitness you should do aerobic exercise at least 3 times a week. To increase your level of fitness, try exercising 4 to 5 times per week.
Imagine that you're exercising. You're working up a sweat, you're breathing hard, your heart is thumping, blood is coursing through your vessels to deliver oxygen to the muscles to keep you moving, and you sustain the activity for more than just a few minutes. That's aerobic exercise; any activity that you can sustain for more than just a few minutes while your heart, lungs, and muscles work overtime. In this article, I'll discuss the mechanisms of aerobic exercise; oxygen transport and consumption, the role of the heart and the muscles, the proven benefits of aerobic exercise, how much you need to do to reap the benefits, and more.
The beginning
It all starts with breathing. The average healthy adult inhales and exhales about 7 to 8 liters of air per minute. Once you fill your lungs, the oxygen in the air (air contains approximately 20% oxygen) is filtered through small branches of tubes (called bronchioles) until it reaches the alveoli. The alveoli are tiny sacs (they kind of look like bunches of grapes, and you have about 300,000,000 in each lung!) where oxygen diffuses (enters) into the blood. From there, it's a beeline direct to the heart.
Getting to the heart of it
The heart has four chambers that fill with blood and pump blood (two atria and two ventricles) and some very large and active coronary arteries. Because of all this action, the heart needs a fresh supply of oxygen, and as you just learned, the lungs provide it. Once the heart uses what it needs, it pumps the blood, the oxygen, and other nutrients out through the large left ventricle and through the circulatory system to all the organs, muscles, and tissue that need it.
A whole lot of pumping going on
Your heart beats approximately 60-80 times per minute at rest, 100,000 times a day, more than 30 million times per year, and about 2.5 billion times in a 70-year lifetime! Every beat of your heart sends a volume of blood (called stroke volume—more about that later), along with oxygen and many other life-sustaining nutrients, circulating through your body. The average healthy adult heart pumps about 5 liters of blood per minute.
Oxygen consumption and muscles
All that oxygen being pumped by the blood is important. You may be familiar with the term "oxygen consumption." In science, it's labeled VO2, or volume of oxygen consumed. It's the amount of oxygen the muscles extract, or consume from the blood, and it's expressed as ml/kg/minute (milliliters per kilogram of body weight). Muscles are like engines that run on fuel (just like an automobile that runs on fuel); only our muscles use fat and carbohydrates instead of gasoline. Oxygen is a key player because, once inside the muscle, it's used to burn fat and carbohydrate for fuel to keep our engines running. The more efficient our muscles are at consuming oxygen, the more fuel we can burn, the more fit we are, and the longer we can exercise.
How aerobically fit can we be?
The average sedentary adult will reach a level of oxygen consumption close to 35 ml/kg/min during a maximal treadmill test (where you're asked to walk as hard as you can). Translated, that means the person is consuming 35 milliliters of oxygen for every kilogram of body weight per minute. That'll get you through the day, but elite athletes can reach values as high as 90ml/kg/minute! How do they do it? Good genes for one, but they also train hard. And when they do, their bodies adapt. The good news is that the bodies of mere mortals like the rest of us adapt to training too. Here's how.
What are the fitness benefits of aerobic exercise?
How our bodies adapt
Here's what happens inside your body when you do aerobic exercise regularly:
1. Your heart gets stronger and pumps more blood with each beat (larger stroke volume). Elite athletes, as I just mentioned, can have stroke volumes more than twice as high as average individuals. But it's not just that. Conditioned hearts also have greater diameter and mass (the heart's a muscle too and gets bigger when you train it), and they pump efficiently enough to allow for greater filling time, which is a good thing because it means that more blood fills the chambers of the heart before they pump so that more blood gets pumped with each beat.
2. Greater stroke volume means the heart doesn't have to pump as fast to meet the demands of exercise. Fewer beats and more stroke volume mean greater efficiency. Think about a pump emptying water out of a flooded basement. The pump works better and lasts longer if it can pump larger volumes of water with each cycle than if it has to pump faster and strain and to get rid of the water. High stroke volume is why athletes' hearts don't pump as fast during exercise and why they have such low resting heart rates; sometimes as low as 40 beats per minute, whereas the average is 60-80 beats per minutes!
3. Downstream from the heart are your muscles, which get more efficient at consuming oxygen when you do regular aerobic exercise. This happens because of an increase in the activity and number of enzymes that transport oxygen into the muscle. Imagine 100 oxygen molecules circulating past a muscle. You're twice as fit if the muscle can consume all 100 molecules than if it can only consume 50. Another way of saying it is that you're twice as fit as someone if your VO2 max is 60ml/kg/min and theirs is 30ml/kg/min. In terms of performance in this scenario, you'll have more endurance because your muscles won't run out of oxygen as quickly.
4. Mitochondria inside the muscle increase in number and activity. Mitochondria are the powerhouses of your cells. They do all the heavy-duty work to keep you moving. They use the oxygen to burn the fat and carbohydrate that makes you go. You'd be nowhere without mitochondria! The good news is that they increase in number and activity, by as much as 50%, in just a matter of days to weeks in response to regular aerobic exercise in adults of all ages.
Burn, baby, burn
I mentioned that fat and carbohydrate are the fuels our muscles burn. The difference between them is that fat is high-test; it contains 9 calories per gram whereas carbohydrate has only 4, and so you get more energy and can go farther on a gram of fat than on a gram of carbohydrate. You want to burn fat because it's such an efficient fuel, plus it's nice to lose some of your excess fat! The catch is that you need more oxygen to burn fat because it's denser than carbohydrate. The good news is that your body gets better at using oxygen and burning fat when you do regular aerobic exercise; like I described, your heart pumps more blood, your muscles consume more oxygen, and you have more mitochondria. Regular aerobic exercise has the potential to turn you into a lean, mean, fat-burning machine!
Aerobics is a gym class, set to music and led by a qualified instructor who will lead you through a variety of structured movements that will raise your heart rate and get blood and oxygen flowing more quickly around your body. Aerobics classes will often include some anaerobic exercises as well.
What is aerobics good for?
A good aerobics class will benefit your body in many ways. A regular workout will:
* strengthen your heart muscle and lungs by making them work harder; with regular exercise, you can lower your blood pressure and cholesterol
* stimulate the circulation of blood and lymph around your body, and so help strengthen your immune system
* help you burn calories and reduce your body fat
* raise your serotonin levels, stimulate your brain to release endorphins and so give you a natural "high" and easing any stress or anxiety
* increase your body strength so you are less prone to injury
* improve the shape and tone of your body.
Before you go
The important thing when you undertake any exercise class is that you choose the right one for your level of fitness. You'll usually find that aerobics classes are offered at beginner, intermediate and advanced levels.
Fitting aerobics into your day: you can timetable aerobics into your day without taking any special precautions; you can go straight back to work afterwards. Just leave yourself time to have a shower as you'll sweat a lot in the class and you'll probably find you want to wash your hair. Your make-up could take some punishment, too, so it's a good idea to take it off beforehand and allow your skin to breathe, and reapply if you want to when you leave.
What to wear: you should wear clothes that allow your skin to breathe, and you to move freely. We've all seen Jane Fonda's lycra body stockings but for us mere mortals, leggings, light tracksuit trousers and a t-shirt will be just as good. Trainers with sweat-absorbing socks are a good idea, too.
How long is it? An aerobics class usually lasts about 45 minutes to one hour.
Precautions
You should not do aerobics if:
* you have a history of heart or respiratory problems
* you have problems with your joints
* you have recently had surgery, or are prone to or recovering from injury.
You should consult your doctor if:
* you have any other medical condition, or are receiving treatment of any kind.
If you are, or think you might be pregnant, you should stick to low-impact aerobics, and can probably find a class specially for mums-to-be. A specially trained instructor will make sure you only do exercises that are appropriate.
If you feel any pain during a class or are unhappy with something you're being asked to do, for any reason, stop.
What to expect at an aerobics class
Aerobics includes a range of movements and exercises that will work on all areas of your body, from gentle jogging on the spot to star jumps, lunges, twists, stretches and tummy crunches.
A good aerobics instructor will take you through different levels of movement. You'll start with gentle low-intensity warm-up exercises including stretches as well as some light jogging, and stepping. You'll be taken gradually up to high-intensity exercises that will really help you burn calories. You will get quite out of breath and will feel your heart working.
Your instructor should then take you back down "through the gears" to gradually lower your heart rate. Borrowing something of yoga, these days some classes include a few minutes of rest or guided meditation to relax and calm you before you leave.
Be prepared for some potentially quite complicated routines and sets; some instructors may also use a lot of jargon to describe movements that you aren't familiar with. If you're not careful, you could end up with someone "grapevining" into you as you are standing there looking for the vegetation. Try not to get self-conscious if you're not doing everything in time, kicking as high, or squatting when you should be diamond-stepping. You'll soon get used to it, and you may as well try to find it hilarious getting it wrong in the meantime. Think of your serotonin levels.
Different kinds of aerobics
Apart from different classes for different levels of fitness, you can also do different kinds of aerobics classes, so you choose the one that appeals to, and suits you best!
High-impact aerobics: High-impact aerobics is a very energetic form of exercise which features lots of movements that lift you off the ground: jumping, hopping and jogging. High impact aerobics is not for the faint-hearted. It is very vigorous. It's probably a class to graduate to rather than start with as you need to be quite fit to do it. It can also be hard on your joints, so this is not a good class for anyone with weaker joints. Because it's so energetic, a high-impact class will make your body release endorphins and serotonin, which will make you feel really refreshed, energised and happy afterwards! And you'll sleep well, too. All of which can't be bad.
Low-impact aerobics: Low-impact aerobics focuses on floor-based exercises, stretches and movements, all of which involve you keeping at least one foot on the floor at all times! Whilst still giving you a good aerobic workout, a low-impact class is a more sedate form of aerobics and doesn't put so much pressure on your joints.
Because it is less vigorous, low-impact aerobics is especially good for:
* pregnant women
* older people
* anyone who is overweight
* people who have weaker joints or frailties of other kinds who are not suited to high-impact aerobic exercises
* people recovering from injury.
Low-impact aerobics for pregnant women: Aerobic exercise strengthens your heart and lungs and helps maintain muscle tone. As long as you choose exercises that are low impact - meaning no high kicks and leaps, and keeping one foot on the ground at all times to minimise stress on your joints - you should be able to continue your routine throughout most of your pregnancy.
Although you could stay fit at home with the help of an exercise video, an aerobics class designed for mums-to-be is your best bet. You'll enjoy the company of other pregnant women, and the expertise of an instructor who understands how to keep you and your baby safe. Many community recreation centres offer antenatal exercise classes. If you're already signed up for a regular aerobics class, let your instructor know that you're pregnant; she can suggest ways to modify movements that may be unsafe or too strenuous for you.
You might also enjoy yoga, particularly in the later stages of your pregnancy; these classes also offer breathing techniques that you can use during labour.
Body conditioning: A body conditioning class focuses on intensive, but low-impact exercises which tone, shape and strengthen muscles. Classes may also include some light, high-repetition weight training. Body conditioning classes often focus on particular areas such as "bums and tums".
"Kickfit" or kick-aerobics: A variation on high-impact aerobics, a kick aerobics class incorporates martial-arts style kicking and other movements to the exercise-routines, but it is non-contact. The class may also include some body conditioning.
Step aerobics: Step aerobics combines low-impact and body-conditioning exercises with a raised platform or "step" to accelerate and intensify the workout to your lower body. Step aerobics is particularly beneficial for developing and strengthening the muscles in your legs, spine and hips, and also works on your co-ordination.
A recent survey has shown that step aerobics is particularly good for strengthening bones.
Spas should provide any equipment you need for an exercise class. This includes a step. Some are bigger than others; the platform height increases with your fitness and ambition!
All stages of the class - from warm up to cool down - are likely to involve the step. Your instructor will show you the right and wrong ways to use it; the "right way" includes, for example, always stepping heel-toe when going onto or off the step, and keeping your back straight.
Be prepared for the fact that the step takes a bit of getting used to. At first, it can feel a bit like rubbing your tummy and patting your head simultaneously but stick with it. Step aerobics can be pretty tough and you can "feel it working" (we're sure you know what we mean), and you should feel results quite quickly.
Dance aerobics: Dance aerobics is a mixed-impact aerobics class with a dance slant - from jazzercise to aeropop and even hiphopics (really). This is a great way to have fun and shape up at the same time.
The movements and exercises in aerobic dance classes will depend a lot on the kind of dance that has inspired it - maybe more ballet, bellydancing or bhangra. Having said this, the exercises will be dance variations on the aerobics theme, rather than the other way around. The class will involve a similar ratio of warm up, high-intensity and cool-down exercises as other classes.
Body pump: Body pump is one of a range of branded classes that are run in exactly the same way, and involve the same exercises across the UK, and in gyms across the world.
Afterwards
After a good aerobics class, you should feel energised (if a bit tired out). Don't let that lovely natural high distract you from the fact that you will also have done a lot of sweating; make sure you allow yourself time to have a shower, or go for a swim afterwards.
If you haven't done the class before you might find you're a bit achey a few days later. This is just because your body has worked some dormant muscles and it should ease off. Definition of Aerobics:
Using the same large muscle group, rhythmically, for a period of 15 to 20 minutes or longer while maintaining 60-80% of your maximum heart rate.
Think of aerobic activity as being long in duration yet low in intensity. Aerobic activities include: walking, biking, jogging, swimming, aerobic classes and cross-country skiing. Anaerobic activity is short in duration and high in intensity. Anaerobic activities include: racquetball, downhill skiing, weight lifting, sprinting, softball, soccer and football.
Aerobic means with air or oxygen. You should be able to carry on a short conversation while doing aerobic exercise. If you are gasping for air while talking, you are probably working anaerobically. When you work anaerobically, you will tire faster and are more likely to experience sore muscles after exercise is over.
Cardiovascular Benefits
Aerobic exercise conditions the heart and lungs by increasing the oxygen available to the body and by enabling the heart to use oxygen more efficiently. Exercise alone cannot prevent or cure heart disease. It is only one factor in a total program of risk reduction; examples of other factors are high blood pressure, cigarette smoking and high cholesterol level.
Additional Benefits of Aerobic Exercise
In addition to cardiovascular benefits, other benefits of aerobic exercise include:
- Control of body fat. (Aerobic exercise in conjunction with strength training and a proper diet will reduce body fat.)
- Increased resistance to fatigue and extra energy.
- Toned muscles and increased lean body mass.
- Decreased tension and aid in sleeping.
- Increased general stamina.
- Psychological benefits - exercise improves mood, reduces depression and anxiety.
Avoid the Aerobic Curve.
The aerobic curve occurs when you begin exercising, increase your intensity level, hit the high point and gradually decrease your intensity level. The goal when exercising aerobically is to hit your target heart rate and maintain it for the entire exercise session. This works the heart muscle more effectively and burns more calories. Think of riding a bike, running or swimming - you start, hit your pace (or target zone), then you maintain your pace until the cool down. As your heart becomes conditioned, you will have to work harder to reach the target zone. Less conditioned athletes will reach their target zones quickly because their heart muscle isn't used to the workload.
Aerobic Classes (step, hi/low, slide, interval etc...)
In an aerobic class, you can do moves in low intensity or high intensity. The level of intensity depends upon how high you bring your arms (not whether the class is low impact or high impact). Aerobic instructors should show class members how to do moves in high or low intensity. Participants should choose their own level of intensity dependent upon their level of fitness and how frequently they exercise.
If you are too tired to continue exercising in an aerobic class, march in place for a while until you can resume exercising. IT IS NOT OK to stop in the middle of an aerobic class because your body is sending extra blood to the muscles. Stopping suddenly can lead to muscle cramping and dizziness (this is why all aerobic classes have a cool down at the end of the aerobic section).
Exercise Frequency
Cardiovascular fitness is an ongoing process and requires consistent reinforcement. To maintain your current level of fitness you should do aerobic exercise at least 3 times a week. To increase your level of fitness, try exercising 4 to 5 times per week.
Imagine that you're exercising. You're working up a sweat, you're breathing hard, your heart is thumping, blood is coursing through your vessels to deliver oxygen to the muscles to keep you moving, and you sustain the activity for more than just a few minutes. That's aerobic exercise; any activity that you can sustain for more than just a few minutes while your heart, lungs, and muscles work overtime. In this article, I'll discuss the mechanisms of aerobic exercise; oxygen transport and consumption, the role of the heart and the muscles, the proven benefits of aerobic exercise, how much you need to do to reap the benefits, and more.
The beginning
It all starts with breathing. The average healthy adult inhales and exhales about 7 to 8 liters of air per minute. Once you fill your lungs, the oxygen in the air (air contains approximately 20% oxygen) is filtered through small branches of tubes (called bronchioles) until it reaches the alveoli. The alveoli are tiny sacs (they kind of look like bunches of grapes, and you have about 300,000,000 in each lung!) where oxygen diffuses (enters) into the blood. From there, it's a beeline direct to the heart.
Getting to the heart of it
The heart has four chambers that fill with blood and pump blood (two atria and two ventricles) and some very large and active coronary arteries. Because of all this action, the heart needs a fresh supply of oxygen, and as you just learned, the lungs provide it. Once the heart uses what it needs, it pumps the blood, the oxygen, and other nutrients out through the large left ventricle and through the circulatory system to all the organs, muscles, and tissue that need it.
A whole lot of pumping going on
Your heart beats approximately 60-80 times per minute at rest, 100,000 times a day, more than 30 million times per year, and about 2.5 billion times in a 70-year lifetime! Every beat of your heart sends a volume of blood (called stroke volume—more about that later), along with oxygen and many other life-sustaining nutrients, circulating through your body. The average healthy adult heart pumps about 5 liters of blood per minute.
Oxygen consumption and muscles
All that oxygen being pumped by the blood is important. You may be familiar with the term "oxygen consumption." In science, it's labeled VO2, or volume of oxygen consumed. It's the amount of oxygen the muscles extract, or consume from the blood, and it's expressed as ml/kg/minute (milliliters per kilogram of body weight). Muscles are like engines that run on fuel (just like an automobile that runs on fuel); only our muscles use fat and carbohydrates instead of gasoline. Oxygen is a key player because, once inside the muscle, it's used to burn fat and carbohydrate for fuel to keep our engines running. The more efficient our muscles are at consuming oxygen, the more fuel we can burn, the more fit we are, and the longer we can exercise.
How aerobically fit can we be?
The average sedentary adult will reach a level of oxygen consumption close to 35 ml/kg/min during a maximal treadmill test (where you're asked to walk as hard as you can). Translated, that means the person is consuming 35 milliliters of oxygen for every kilogram of body weight per minute. That'll get you through the day, but elite athletes can reach values as high as 90ml/kg/minute! How do they do it? Good genes for one, but they also train hard. And when they do, their bodies adapt. The good news is that the bodies of mere mortals like the rest of us adapt to training too. Here's how.
What are the fitness benefits of aerobic exercise?
How our bodies adapt
Here's what happens inside your body when you do aerobic exercise regularly:
1. Your heart gets stronger and pumps more blood with each beat (larger stroke volume). Elite athletes, as I just mentioned, can have stroke volumes more than twice as high as average individuals. But it's not just that. Conditioned hearts also have greater diameter and mass (the heart's a muscle too and gets bigger when you train it), and they pump efficiently enough to allow for greater filling time, which is a good thing because it means that more blood fills the chambers of the heart before they pump so that more blood gets pumped with each beat.
2. Greater stroke volume means the heart doesn't have to pump as fast to meet the demands of exercise. Fewer beats and more stroke volume mean greater efficiency. Think about a pump emptying water out of a flooded basement. The pump works better and lasts longer if it can pump larger volumes of water with each cycle than if it has to pump faster and strain and to get rid of the water. High stroke volume is why athletes' hearts don't pump as fast during exercise and why they have such low resting heart rates; sometimes as low as 40 beats per minute, whereas the average is 60-80 beats per minutes!
3. Downstream from the heart are your muscles, which get more efficient at consuming oxygen when you do regular aerobic exercise. This happens because of an increase in the activity and number of enzymes that transport oxygen into the muscle. Imagine 100 oxygen molecules circulating past a muscle. You're twice as fit if the muscle can consume all 100 molecules than if it can only consume 50. Another way of saying it is that you're twice as fit as someone if your VO2 max is 60ml/kg/min and theirs is 30ml/kg/min. In terms of performance in this scenario, you'll have more endurance because your muscles won't run out of oxygen as quickly.
4. Mitochondria inside the muscle increase in number and activity. Mitochondria are the powerhouses of your cells. They do all the heavy-duty work to keep you moving. They use the oxygen to burn the fat and carbohydrate that makes you go. You'd be nowhere without mitochondria! The good news is that they increase in number and activity, by as much as 50%, in just a matter of days to weeks in response to regular aerobic exercise in adults of all ages.
Burn, baby, burn
I mentioned that fat and carbohydrate are the fuels our muscles burn. The difference between them is that fat is high-test; it contains 9 calories per gram whereas carbohydrate has only 4, and so you get more energy and can go farther on a gram of fat than on a gram of carbohydrate. You want to burn fat because it's such an efficient fuel, plus it's nice to lose some of your excess fat! The catch is that you need more oxygen to burn fat because it's denser than carbohydrate. The good news is that your body gets better at using oxygen and burning fat when you do regular aerobic exercise; like I described, your heart pumps more blood, your muscles consume more oxygen, and you have more mitochondria. Regular aerobic exercise has the potential to turn you into a lean, mean, fat-burning machine!
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