Fitness professionals are divided when it comes to cardio training. Some believe it should make up the bulk of your program, while others suggest skipping it altogether. Of course, like most things in life, it’s actually much more nuanced.
The fundamental purpose of cardio training is to, well, train your cardiovascular system – your heart, lungs, and circulatory system – to better transport oxygen to your cells. But it comes with many other side benefits:
- Lower blood pressure
- Increased elasticity and resilience of soft tissues
- A stronger immune system
- Improved sleep
- Greater longevity
- Higher metabolism
Training your cardiovascular system is very important – there’s no question about that. But what form of cardio exercise, and how much, is really necessary? Read on to learn more.
What the experts say
The Physical Activity Guidelines for Americans, 2nd edition, published by the U.S. Department of Health and Human Services, Office of Disease Prevention and Health Promotion, recommends how much physical activity we need to be healthy. The recommendations are based on the latest scientific evidence supporting the connections between physical activity, overall health and well-being, disease prevention and quality of life. And here they are:
150 minutes per week of moderate-intensity aerobic activity, or 75 minutes per week of vigorous aerobic activity, or a combination of both, preferably spread throughout the week;
At least two days per week of moderate to high intensity muscle-strengthening activity (such as resistance or weight training).
Are you meeting these guidelines? Studies show only one in five of us are.
Defining intensity levels
What is “moderate” versus “vigorous” intensity when it comes to aerobic – or cardiovascular – exercise?
A moderate intensity means your heart will beat faster and you’ll breathe harder than normal, but you’ll still be able to talk in short sentences. On a one-to-ten scale, you’re at a 5 or 6. Moderate-intensity activities might include:
- Walking briskly (at least 2.5 miles per hour)
- Water aerobics
- Dancing (social or ballroom)
- Cycling on flat terrain at 10-12 mph
Vigorous activities push you harder and require a higher effort. You’ll probably get warm and begin to sweat. You’ll only be able to say a word or two at a time. On the one-to-ten scale, you’re at a 7 to 9. Vigorous intensity looks like this:
- Hiking uphill or with a heavy backpack
- Zumba or other aerobic dance classes
- Heavy yardwork like continuous digging or hoeing
- Cycling on the flat faster than 12 mph, or hill climbing
- Jumping rope
The four flavors of cardio
Although “cardio” is a broad term, and it’s used to refer to a lot of different activities, there are really just four main types.
Aerobic Training (“aerobics”)
Aerobic training means exercise that targets the circulatory system and the lungs. It doesn’t have to be fast, and it doesn’t have to be for any specific amount of time. If you are challenging your body’s ability to take in oxygen and distribute it to your cells, that’s aerobic training.
LSD (Long Slow Distance)
Long Slow Distance training is the go-to cardio activity for most people. Pick a pace, keep it mostly steady, and go for a long time or distance. This is what marathon runners, cyclists and even swimmers do, as it follows a training philosophy that “if you want to be able to do more of something, do more of that thing.”
A variation on this is called LISS (low-intensity, steady state) which takes the distance factor out of the equation.
On the plus side, this type of training is straightforward. You just maintain a slow to moderate pace of whatever movement you’re doing, and you go for a set time or distance at that pace. It doesn’t require a whole lot of thinking or planning.
But there are a few downsides. One is that it can become kind of a mindless rut. After a stressful day, it’s often easier to lace up your shoes and go for a walk or run than to strength train, or something more specific to your goals.
Also, depending on the activity, injuries can be prevalent with this form of training. This is because of repetitive movement patterns. Statistics indicate over 50% of runners will get injured every year, and some even estimate as high as 90%. (Another reason why cross-training is such a good idea.)
HIIT (High Intensity Interval Training)
HIIT has been the “thing” in the fitness world for some time now.
Interval training means a period of active work, followed by a predetermined amount of rest, before repeating the active work portion. But beyond that, there’s a lot of room for variation.
There’s regular interval training, such as doing one minute of jogging followed by one minute of walking until you make it around the block or however long you planned to go. Typically, the work-to-rest ratio is 1 for 1, or 1 for 1.5.
To reach a higher (“vigorous”) intensity, the goal is to provide only enough rest to allow for you to do one more round of near-maximum effort. A work-to-rest ratio of 1 for 0.5 or even 1 for 0.25 will do this.
Interval training, no matter what the intensity, is so popular because it provides many of the benefits of long slow distance training, but with some extra bonuses:
- Workout time is shorter
- Bigger cardio payoff for the time invested – more work per minute
- A more sustained metabolic effect: keeping the heart rate up longer, improving the amount of oxygen the body actually uses
The biggest downside to HIIT is that it’s pretty hard – and so can be less enjoyable if you’re new to exercise.
Named for a Japanese researcher, Dr. Izumi Tabata, Tabata training a very specifically structured variation of HIIT. It’s believed to be the ideal interval structure for higher intensity work, such as sprints. Over the course of four minutes, you perform repeated intervals of active work for 20 seconds, followed by 10 seconds of rest. During those 20 seconds of work, the goal is to go as hard as possible. Those 10 seconds of rest feel more like two seconds after a few rounds!
But because it’s short, a Tabata-structured workout is doable for almost everyone.
How much cardio is right for you?
We’ve established that cardio training is an important part of a healthy lifestyle. But what that training looks like, and how much you do of it, depends on your goals, preferences, and needs. One thing it doesn’t look like is spending hours on the elliptical or treadmill.
Establishing your personal fitness goals is crucial to determining the type, volume, and duration of exercises in your routine, including cardio training.
For example, you may have a specific endurance goal, such as running a marathon or a hiking vacation carrying a heavy pack. A marathoner will certainly need to spend a lot of time in LSD-style training, with strength training to prevent injuries and periodic interval training to boost metabolism. A hiker will benefit more from training for endurance by carrying heavy weights in various combinations than by running for hours.
For most people without a specific endurance goal, any strenuous exercise that gets the heart pumping harder is sufficient “cardio” training. If you’re spending time on activities you enjoy, and you’re doing some hard work, you’re probably already doing enough cardio for your health.
What about weight loss?
It’s a widely-held belief that you have to do lots of cardio to burn calories in order to lose weight. But too much cardio and not enough muscle-building strength training can backfire. High intensity cardio exercise activates stress-based hormones such as cortisol – too much of which can lead to excess fat storage. For a full analysis on this subject, read The Great Debate: Cardio vs. Weights. LINK
The takeaway: focus on you
Everyone needs a strong heart and lungs. After all, they’re what keep us alive and kicking. That should be the primary reason for incorporating cardio exercise into your lifestyle. But beyond that, consider what goal you are working to achieve, and structure the type of cardio you do around that.
Also consider what gives you the most enjoyment. If it’s not fun or rewarding, then it’s going to become something you dread. Experiment with lots of different activities and find one you like. Maybe it’s tennis, or Zumba, or swimming, or even pickleball!
Take the government guidelines and see how you can fit in the recommended volume of activity into your week. Is it 30 minutes a day, five days per week? Or two vigorous workouts of 45 minutes each and two moderate-intensity 30 minute sessions? The combinations are endless!