Select Page

So maybe you are thinking: ‘how can I, a 50 lb. overweight couch potato go out and run for 20 minutes and get my heart rate to 65% of its max without having a coronary on the side of the road?’. Well, first of all don’t. You want to regularly get an intense cardio workout to be a healthy person, not a dead one.  So, take it slowly at first.

You may begin by walking a short distance every day and progressively increase the distance. Then, or in addition, increase the speed at which you exercise. If you try to go out and immediately start exercising the way athletes do, you’re going to hurt yourself. Start out gradually and slowly increase distance and or speed. Especially if you have a lot of extra weight, listen to how your body feels. It may take a month or more of diet and mild exercise before you are ready to go all out. If you don’t have much weight to lose, you may only need a couple weeks of mild exercise.  Just listen to your body.

Great Activities for an Intense Cardio Workout

There are a lot of things you can do for cardio exercise. Some are certainly more beneficial than others. Just remember, if you can get your heart rate up for at least a solid 15 minutes, it counts as cardio.


Running is pretty much the best it gets! Perhaps the most practical too since it can be done by almost everyone at any time. It’s also easy, if you focus, to keep your heart rate at the level it should be. Running is perhaps the best cardio exercise because you can directly control how much intensity you are putting forth. With sports and other exercises, you have limitations on how “all out” you can be. For instance, if your cardio is basketball, then if your team is down court passing the ball around, you just can’t give 100% because your movement is limited. Also, if you are on the bench then you are giving about 0% unless you are running in place.


Swimming is a great choice too, but not practical for everyone. For instance, when I swim laps it is really controlled drowning. Now this is good from a cardio exercise perspective because, although I don’t move fast or efficiently, I have to exert everything I have just to stay above water long enough to keep air in my lungs. On the other hand there are those like my wife that exert little effort and glide through the water like a dolphin.  She has the technique down pat. For her, just swimming laps isn’t enough to get a really intense cardio workout because she is just too good at it. For it to be worth it for her, she would have to consciously swim at her highest level.


Running is better than jogging; I won’t lie to you.  Jogging is still a good exercise, particularly over long distances.  But for some people running is just a challenge they are not willing to face, and that’s fine.  But anyone can.  Whatever point you are at, if you are constantly pushing for faster times, you can learn to run. But whether you are a runner (better) or a jogger (good), keep at it.


Sports are a fun way to exercise almost without even knowing it . However, keeping your heart rate up can be difficult or impossible to do depending on the sport and who it’s with. If you are playing a pickup game of basketball with some buddies who happen to be on the local college team, then you will probably get a great cardio workout. If you are playing with a bunch of old fat Kobe Bryant wannabes, then your workout may suffer. Also, no matter who you are playing with, golf, ping pong, and bowling probably aren’t the best cardio sports in the world.


Aerobics can be good, but not usually a great choice. Programs like p90x and Tae-Bo can be pretty intense, but oftentimes they are too focused on “having fun” or combining light strength training with light cardio. If you are going to do aerobics for your cardio workout, then you should be panting like it’s going out of style the whole time, and if you aren’t swimming in sweat by the time it’s over, you need a new instructor. Many a fat lady has done aerobics regularly and still managed to be a fat lady.

Being a healthy person requires cardio exercise, there’s just no way around it. However, being intense and pushing yourself is essential to getting the best results. You can time yourself and try to get faster, change your exercise routine every few months, or reward yourself for hitting a certain goal in speed or distance; whatever you need to be sure that you don’t fall into a rut. Exercise is an essential part of being healthy, but doing the same thing the same way every time will only get you so far.

How Long Should My Intense Cardio Workout Be?

Cardio exercise should last a minimum of 15 minutes, and the emphasis is on minimum. If you want significant benefit, you should be prepared to go for 20 minutes or more. Most people don’t find running particularly enjoyable, maybe do-able while listening to music, but they still do it; that’s what you must do. Having said that, there are 2 components to a good workout that you need to be aware of; intensity and duration. So although you might only go for 15 minutes, if you were to run at about 80% of your max heart rate the entire time, you would still get a great workout.

You can justify exercising for a relatively short period of time if the intensity is high (as long as it’s at least 15 minutes). The longer it lasts, the less intense it needs to be. So you could walk for 60 minutes or run for 15 and expect similar results.  When you do a cardio workout you ought to aim for about 20 minutes even though 15 is do-able. The reason is that most people find it difficult to stay intense for very long without distraction. It is very difficult to do. These types of people tend to do better listening to music, watching tv, etc., while they exercise. Therefore, their intensity tends to be a bit lower. In that case, we can make up for the intensity by increasing the duration.

The Frequency of Your Cardio Exercises

The “experts” say that you should exercise 5 times a week for at least 20 minutes and that’s a good rule to go by. That may sound like a lot, but consider that 20 minutes is only 1.4% of your day. Also consider that exercise will help you live considerably longer, so you’ll probably have more healthy days to enjoy anyway. This doesn’t mean that you need 5 days of cardio exercise though. Some of those days might be strength training. The healthiest way to exercise is a combination of both.

However, you should do cardio at least twice a week. If you only do one exercise though, make it cardio. Although strength training work-outs are great for helping you with flexibility and strength, they ultimately impact your heart very little. Big muscles won’t help you live longer or do as much internally, but intense cardio workouts do. Besides, if you can run for 20 minutes 5 days a week, your flexibility and strength are probably at least sufficient anyway. Cardio is the most important exercise to improve your length and quality of life. That being said, strength training is important too.

What Does an Intense Cardio Workout Look Like?

Cardio exercise is a sustained exercise that forces your heart to beat relatively quickly for an extended period of time. This is the most recognized form of exercise because it is easy to do, no assembly required. A cardio exercise must last at least fifteen minutes to provide significant benefit to your heart, but unless you are going really hard, this is not enough either. Most cardio workouts last anywhere from 20-60 minutes. The idea is that you force your heart to work really hard for a while which causes your it to build strength over time and become more efficient so that it actually beats more slowly during daily activities than it used to, and yet delivers the same amount of blood to your cells.

It also has other benefits such as expanding blood vessels, which further decreases the workload on your heart and your chances of heart disease. Your heart can only last for so many beats before it just runs out of life. So, although cardio exercise causes your heart to beat much faster than normal, it is only for a relatively short period of time. During the non-exercise portion of the day your heart will beat far fewer times than if you didn’t exercise at all.

Great Cardio Demonstrated

Let’s say your heart rate is about 80 bpm (beats per minute) during the day. You start exercising and after a few months your average heart rate is down to about 75 bpm. Although it may not seem like a huge difference, 80 bpm is the same as 42,048,000 beats per year whereas 75 bpm is 39,420,000 per year. Remember your heart never stops beating, but by only lowering your heart rate 5 bpm, you save your heart 2.6 million beats each year. Trying forming a fist 2.6 million times in a row and then decide if this is a significant difference. Let me give you another scenario to really drive this idea home. A resting heart rate of about 60 bpm beats about 16 million fewer times than a heart rate of 90 bpm over a lifetime.

The point here is clear; the more times your heart beats, the closer it is to stopping, no matter how healthy you are! However, you can get many more beats out of a healthy heart than a docile one. Good cardio exercise will allow your heart to beat tens of millions of fewer times in your life; thus, it will last you longer. And as you strengthen your heart, you will also increase the number of times your heart is able to beat before it poops out.

How to do and Intense Cardio Workout

To make it simple, a cardio workout is nothing more than a continuous activity lasting a minimum of 15 minutes and keeps your heart rate high enough. The “level” at which your heart beats for those 15 (or more) minutes is very significant in regards to how much benefit you receive. The longer you exercise, or the faster your heart beats, the more benefit you will get, to a degree of course. Having said that, this isn’t to say if you run for 2 hours you will get precisely 4 times the benefit of running for 30 minutes. In fact, quite the contrary. The longer you do cardio, the more benefits you will reap for your heart, but after a certain point the rate at which you gain those benefits decreases.

The following chart gives a general idea of benefits received over time for a cardio workout. Notice that the payback is always increasing, but over after long enough, the benefits are hardly even worth the time. That’s why ultra-runners, although healthy, don’t live significantly longer than other healthy people. Sure they spend hours a day running, but the most benefit comes in the first hour. After that, more running can almost erase some of the benefits.

Exercise Benefit Over Time


Determining Your Target Heart Rate

After you have exercised long enough you will be able to tell if you are exercising at the level you should be. Try to exert about 70%-80%  of what you could possibly give if you were to give everything you have. However, the rate at which your heart is beating is the best indicator of your workout level. First of all you need to determine your maximum heart rate. Simply subtract your age from 220.


So if I am 26 years old, my max heart rate is 220-26=194. When you do an intense cardio workout you should reach roughly 65% or more of your maximum heart rate for a period of at least 15 minutes, but more like 20-30 is best. So, using the previous value of 194 for my heart rate,


This is the lowest that my heart rate should be at for at least 15 minutes to get a “good” cardio workout.

Time vs. Intensity for Your Intense Cardio Workout

When you are doing cardio at about 70%, a short 15 minutes may not be enough time to give your heart substantial benefit. If you wish to do cardio at that level, 25-30 minutes would be more appropriate. Some folks like to stay right up at 80% such that a 15 minute intense run can give the same benefit (or maybebetter), than a 30 minute jog at the lower end of 70%.

So, if you are an intense person and can keep yourself pushing hard, you can get your exercise done faster and more efficiently.  That being said, there is nothing wrong with doing longer at a lower intensity.  This is especially true if you are training for long distance. If you prefer to do a less rigorous exercise like taking a brisk walk, that’s great too, but plan on at least 30 minutes. It is longer, but it is also easier and arguably more enjoyable.

Getting used to doing cardio

This may sound an awful lot of information just about how fast your heart beats during exercise.  However, if you monitor it for a while, you will learn what it feels like. As you exercise and take your heart rate at various times, you will come to know what each level of intensity feels like. You will also know what not-so-intense feels like.  When you can feel that you are holding back, just ratchet up your intensity a little bit until you know you are in the zone you need to be in.  Pretty soon you will just ‘know’ where your body is at.

Warm-Up Exercises to Prepare Your Body for Your Intense Cardio Workout

Everybody needs to get warmed up before exercising, especially those that need to lose weight and out of shape. Stretching is fine, but it’s over-rated. Here’s the reason. The point of “warming up” or “stretching” is to supply more blood to the soon-to-be effected area. When your muscles are “cold” it simply means they don’t have much blood circulating in them. They are warm when you do. Your body is smart enough to know that when you start using a muscle it needs to send blood there. Stretching does this.

Warming up is better than stretching

Another, more effective way, is to actually flex muscles that you are going to use. What this means is to do a quick, but light “workout” of sorts. For example, if you were going to play basketball, how would you warm up most effectively (think about how the pros do it)? Would you stretch out your muscles one by one and then run out on the court ready for a full-on game? Or would you do some practice shots, lay-ups, free throws, 3 pointers, and so on? The same applies to exercise. Here’s an example of what you might do before going running:

  • Trunk twists-10
  • Push ups-10
  • Sit ups-10
  • Squats-10
  • Calf raises-10

Do this 2-3 (relatively slow) times followed by a slow, deliberate jog for about 2 minutes.  Now you are ready to go on your run!

Listen to your body

For some, this is adequate for a full, intense 15 minute run. You may need more or even less. Again, listen to your body and determine what it needs. You could waste your time stretching your biceps, triceps, legs, etc. This could take a long time. That’s fine, but why should you stretch for 10 minutes when you can warm up sufficiently in about 3 minutes? Consequently, you should do this for two reasons. First of all it saves time; it’s just faster. Secondly, it’s more realistic. Stretching is not the same as working muscles. Working them lightly is just logically a better way to prepare them for use and it turns out that studies show this too.  Stretching, as opposed to “warming up” can actually slow you down.

Again, you may need to do more than this. If you are older, out of shape, or new to this kind of exercise you may not be ready for an intense run by just doing the above warm-ups. However, you still probably don’t need to stretch every single muscle in the traditional sense.

The Cooldown After Your Intense Cardio Workout

It is also important to “cool down” after exercise.  But this can be as simple as a brisk walk for a few minutes, say following an intense run. You may need more. Consider stretching too. Although stretching is not optimal prior to exercise, it is great following it. Cooling down is just slowing the blood flow to your muscles so it can gradually return to a resting level, sort of the opposite of warming up. It is particularly important at the end of an intense cardio workout to slow down before doing any stretching though. Don’t just stop and stretch because it could cause muscle cramps. Warming up and cooling down are important in avoiding cramps and injuries and reducing muscle soreness later on.