What is aerobic exercise?
Aerobics is a form of physical exercise that combines rhythmic aerobic exercise with stretching and strength training routines with the goal of improving all elements of fitness (flexibility, muscular strength, and cardio-vascular fitness). It is usually performed to music and may be practiced in a group setting led by an instructor (fitness professional), although it can be done solo and without musical accompaniment. With the goal of preventing illness and promoting physical fitness, practitioners perform various routines comprising a number of different dance-like exercises. Formal aerobics classes are divided into different levels of intensity and complexity and will have five components: warm-up (5–10 minutes), cardiovascular conditioning (25–30 minutes), muscular strength and conditioning (10–15 minutes), cool-down (5–8 minutes) and stretching and flexibility (5–8 minutes). Aerobics classes may allow participants to select their level of participation according to their fitness level. Many gyms offer a variety of aerobic classes. Each class is designed for a certain level of experience and taught by a certified instructor with a specialty area related to their particular class.
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 (also known as "cardio" in gym lingo), which is 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.
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 microscopic sacs 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 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 (cardiovascular system) to all the organs, muscles, and tissues 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.
Why do you need aerobic exercise?
The average sedentary adult will reach a level of oxygen consumption close to 35 ml/kg/minute 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 90 ml/kg/minute! How do they do it? They may have 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.
Cardiovascular exercises can be done at home. There are many you can do with little to no equipment, too. Always warm up for 5 to 10 minutes before starting any exercise.
Equipment: gym shoes (sneakers), jump rope
Benefits: Jumping rope helps develop better body awareness, hand-foot coordination, and agility.
Safety: Your jump rope should be adjusted for your height. Stand with both feet on the middle of the rope and extend the handles to your armpits. That’s the height you’re going for. If it’s too long, cut or tie it to avoid tripping on the rope.
Duration and frequency: 15 to 25 minutes, 3 to 5 times per week
Following a jump rope circuit is a great indoor or outdoor activity, though you’ll want to make sure you have plenty of space. Your circuit routine should take 15 to 25 minutes to complete.
If you’re a beginner:
- Start by jogging forward as you swing the jump rope over your head and under your feet. Do this move for 15 seconds.
- Next, reverse your direction and jog backward as you continue to swing the jump rope. Do this move for 15 seconds.
- Finish your set by doing a hopscotch jump for 15 seconds. To do this move, jump rope in place, and as you jump, alternate between jumping your feet out to the sides and then back to the center, similar to how you’d move them while doing jumping jacks. Do this move for 15 seconds.
- Rest for 15 seconds between sets.
- Repeat 18 times.
If you’re an intermediate exerciser, you can perform the moves for 30 seconds and rest for 30 seconds between sets. The advanced circuit should be performed for 60 seconds at a time, followed by 60 seconds of rest.
Aerobic strength circuit
Equipment: gym shoes (sneakers), sturdy chair or couch for dips
Benefits: This exercise increases heart and cardiovascular health, builds up strength, and tones major muscle groups.
Safety: Focus on proper form with each exercise to avoid injury. Keep your heart rate at a moderate level throughout. You should be able to carry on a brief conversation during this exercise.
Duration and frequency: 15 to 25 minutes, 3 to 5 times per week
This aerobic circuit is designed to get your heart rate up. Perform the following strength exercises for 1 minute:
- torso twist
Then jog or march in place for 1 minute for your active rest. This is one circuit. Repeat the circuit 2 to 3 times. You can rest for up to 5 minutes between circuits. Cool down afterward with some light stretching.
Running or jogging
Equipment: running shoes
Benefits: Running is one of the most effective forms of aerobic exercise. It can improve heart health, burn fat and calories, and lift your mood, just to name a few.
Safety concerns: Choose well-lit, populated running routes. Let someone know where you’ll be.
Duration and frequency: 20 to 30 minutes, 2 to 3 times per week
If you’re a beginner, run for 20 to 30 minutes twice a week. Your pace should be conversational during the run. You can alternate between 5 minutes of running and 1 minute of walking to start. To stay injury-free, always stretch after your run.
Equipment: gym shoes (sneakers)
Benefits: Walking daily can reduce your risk of heart disease, obesity, diabetes, high blood pressure, and depression.
Safety: Walk in well-lit and populated areas. Choose shoes that offer good ankle support to reduce your risk for injury.
Duration and frequency: 150 minutes per week, or 30 minutes 5 days a week
If walking is your main form of exercise, aim to get 150 minutes per week. This can be broken down into 30 minutes of walking 5 days a week. Or, walk briskly for 10 minutes at a time, 3 times each day.
You can also use a fitness tracker to keep tabs on how many steps you take each day. If your goal is to walk 10,000 steps a day, start with your base (current amount you walk) and slowly up your daily step count. You can do this by increasing your daily steps by an extra 500 to 1,000 steps a day every 1 to 2 weeks.
So, once you’ve identified your base, add an extra 500 to 1,000 steps. Then, 1 to 2 weeks later, increase your daily step count by an additional 500 to 1,000 steps.