How Cardio Strengthens Your Heart
Your heart is a muscle, and just like your arm or leg muscles, it gets stronger the more you use it. When you do cardio regularly, your heart grows slightly larger and can pump more blood with each beat. A typical resting heart rate for most people is between 60 and 100 beats per minute, but highly trained endurance athletes can have resting heart rates as low as 40 beats per minute because their hearts are so efficient. A stronger heart means your body can deliver oxygen to your muscles faster, letting you run longer and play harder without getting tired.
Aerobic vs. Anaerobic Exercise
Aerobic exercise means “with oxygen” — during activities like jogging or swimming laps, your body uses oxygen to produce the energy your muscles need. As long as you can breathe in enough oxygen to keep up with your muscles’ demands, you’re exercising aerobically. But when exercise gets very intense, like during an all-out sprint, your body can’t get oxygen to your muscles fast enough and switches to anaerobic (“without oxygen”) energy systems. Anaerobic exercise can only last a short time before your muscles start to burn from lactic acid buildup, which is why you can jog for 30 minutes but can only sprint for about 30 seconds.
How Much Cardio Do Kids Need?
The CDC recommends that children and teenagers get at least 60 minutes of physical activity on most days, and most of that time should be moderate-to-vigorous cardio exercise. Moderate activity means things like brisk walking or casual biking, where you can still talk but might feel a little out of breath. Vigorous activity means things like running or playing basketball, where talking in full sentences becomes difficult. The good news is that you don’t have to do all 60 minutes at once — three 20-minute sessions of active play count just as much.
Types of Cardio Activities
There are so many ways to get your cardio in that everyone can find something they enjoy. Team sports like soccer, basketball, and field hockey keep your heart pumping while you have fun with friends. Individual activities like swimming, running, and cycling let you work at your own pace. Even everyday activities count — walking to school, playing chase at recess, or racing your friends to the playground all get your heart working harder. Jumping rope is one of the most effective cardio exercises, burning more calories per minute than almost any other activity.
The Benefits of Regular Cardio
Regular cardiovascular exercise provides powerful health benefits that last a lifetime. Research shows that just 30 minutes of moderate cardio exercise five days a week can reduce the risk of heart disease by about 35 percent. Cardio also lowers blood pressure, improves cholesterol levels, and helps regulate blood sugar. Beyond your heart, cardio exercise strengthens your lungs, boosts your immune system, and increases blood flow to the brain, which improves focus and memory. People who do regular cardio also tend to sleep better and feel less stressed.
Measuring Exercise Intensity
One easy way to tell how hard your heart is working during cardio is the “talk test.” If you can chat normally, you’re doing light activity. If you can talk but not sing, you’re at a moderate level. If you can only say a few words before needing a breath, you’re exercising vigorously. Another method is to check your heart rate — you can feel your pulse on the side of your neck or on the inside of your wrist and count the beats for 15 seconds, then multiply by four. As you get fitter, you’ll notice that activities that used to leave you gasping for air become much easier.
Getting Started Safely
If you’re new to cardio exercise, the most important thing is to start slowly and build up gradually. Begin with activities you enjoy so you’ll want to keep doing them. Always warm up with a few minutes of easy movement before pushing hard, and cool down afterward to let your heart rate return to normal. Drink plenty of water before, during, and after exercise, especially on hot days. Pay attention to how you feel — a little tiredness is normal, but sharp pain or dizziness means you should stop and rest. The most effective cardio routine is the one you actually enjoy doing, because that’s the one you’ll stick with.
OtterKnow Kids Encyclopedia