How can I build/improve my cardio as quickly and efficiently as possible? I am not interested in weight loss or burning calories, just in allowing me to run for longer amounts of time without taking a break.

I have a treadmill available for this effort.

Edit: I am not training for any particular sport or event, I just want the best results. I would classify my fitness level at "moderate" - I'm not overweight and have lifted weights on and off for 10 years.

A more direct question is: in 20 minutes on a treadmill, is it more effective to jog for 19 minutes, run for 15 minutes or sprint for 10 (where the off-time is spent walking/recovering)?


7 Answers 7


I would highly recommend looking into Tabata/Interval training to build your cardio quickly (What is tabata? How effective is it?). If there's a reason for you to build it (are you competing in some sport activity), then I would incorporate that specific activity into the training - in other words, don't run on a treadmill if you're looking to improve your swimming.

  • Very interesting - thanks for the link. I'll have to try that out.
    – Haphazard
    Aug 8, 2011 at 14:35
  • This isn't a workout for long-term endurance. It would help increase the speed you can hold for 2-3 minutes, but it is not ideal training for runs 10 times as long.
    – Evan
    Jul 1, 2013 at 15:25

I have your answer!

Use the amazing new science of exercising in a specific heartrate zone - neither more nor less - for specific results.

For example, http://www.thewalkingsite.com/thr.html

First calculate your MHR (max heart rate) as described.

Next, buy the cheapest heartrate monitor you can buy - order it now. (They only cost a few dollars. They are all exactly the same, so it is utterly pointless buying an expensive one.)

Next, you should exercise at 70% of your MHR. Allow plus or minus say 3 or 4 each way. (So for me, it's 120. So, I have to keep it between 116 and 124, for example.)

Next, get yourself up to one hour a day but only at exactly that 70% heartrate - no faster (or slower) heartrate.

You will find your improvement is incredibly fast.

At first I was only able to jog 30 minutes a day AND I had to break that up in to three groups of ten with a rest between. Again, very strictly keeping to my 70% rate at all times. (Do not do less than 10 minutes "sections" - force yourself to keep it up for 10 mins.)

Now as little as an incredible two months later, I can very easily jog/run at that 70% level, for two HOURS with no problem, at any time, almost any day. (I run for an hour basically everyday currently.) Plus I'm an old fart. If you carefully and aggressively stick to the 70% level (resist the temptation to go harder) your improvement will be astounding. And you must do at least 30 minutes a day, starting today.

Tip: if presently you find it hard to reach that 70% heartrate, while jogging: try this: find a hill and just "walk quickly" up the hill. (If it's a steep hill, just climb slowly up the hill.) Watch your heartrate monitor carefully and get your heartrate at exactly that magic 70% level. Of course you could I guess use any of the popular machines, treadmills, etc.

I only learned about this 70% business here on this web site, with thanks to BackInShapeBuddy and the rest. So I hope it helps other readers.

Further thinking: your diet has to be critical. Have you read Protein Power Lifeplan by the Drs Eades. It could change your life - of course, every diet science has people who do and don't "believe" in it. However it's dead easy to try or say 3 weeks, and the change in your running energy for very many people is astounding. It's by no means a "painful" dietary regime, you eat as much as you can stuff in your face, so it's painless to try and if it works for you, you have a new lease on life.

  • A very interesting technique. Unfortunately, an hour per day is far more time than I am willing/able to put into this. I have started running again only because my wife bought a treadmill for our basement.
    – Haphazard
    Aug 8, 2011 at 18:22
  • @Haph what about 30 minutes a day, then! Don't forget to buy a cheap heart rate monitor.
    – Fattie
    Aug 9, 2011 at 8:18
  • 1
    "Most people don't realize that running 7-10 miles isn't a whole lot different than running 1-2 if you're disciplined about pace." an outstanding point. You just need a $2 cardiometer
    – Fattie
    Aug 11, 2011 at 18:39
  • 6
    The expression "Use the amazing new science of exercising" makes me want to puke. Please don't misuse the word science, it's enough that journalists do it.
    – M.K.
    Aug 14, 2011 at 16:38
  • 4
    I won't downvote this, but I would not use ANY formula that involves the fatally flawed 220-age misconception. Additionally, I would be wary of using any measurement metric to base your exercise level on (such as heart rate) that can be affected by a large degree by outside factors (Such as how much caffeine you drank this morning).
    – JohnP
    Jan 2, 2013 at 22:29

So more oxidative enzymes means you have a higher capacity for going longer and harder.

And it turns out that an initial study (16) on the effect of HIIT training on oxidative enzymes demonstrated massive increases in skeletal muscle oxidative enzymes in subjects engaging in 7 weeks of intense cycling sprints, in which subjects performed four to ten 30-second maximal cycling sprints followed by 4-minute recovery intervals, on just three days per week.

But what about HIIT vs. aerobic cardio?

Another 6-week training study (5) compared the increase in oxidative enzymes that resulted from either:

1) four to six 30-second maximal effort cycling sprints, followed by 4.5-minute recovery bouts and performed 3 days per week (this is classic HIIT training)…


2) 40–60 minutes of steady cycling at 65% VO2 max (an easy aerobic intensity) 5 days per week.

The levels of oxidative enzymes in the mitochondria among subjects who performed the HIIT program were significantly higher – even though these folks were training at just a fraction of the volume of the aerobic group.

How could this favorable endurance adaptation happen with such short exercise periods?

It turns out that the increased mitochondrial density and oxidative enzyme activity from HIIT is caused by a completely different message-signaling pathways than traditional endurance training.

In this alternative pathway, a “master switch” is activated that promotes the favorable endurance adaption. This master switch is known as PGC-1α (pronounce this as “pee-gee-see-one-alpha” if you want to impress your friends), which stands for “peroxisome proliferator-activated receptor-g coactivator-1α”. PGC-1α causes that favorable increase in mitochodnrial density and oxidative enzyme activity, but can be activated by two completely separate signaling pathways – the calcium–calmodulin kinase (CaMK) pathway or the adenosine monophosphate kinase (AMPK) pathway (15).

Continuous, voluminous endurance training seems to activate the master PGC-1α switch via the former pathway, while intense interval training activates it via the latter pathway



High Intensitivity Training (HIT) is highly recommended to improve your cardio/endurance/stamina. I consider my self as well fit overall, with top grades in every running test I've taken. To achieve these results, I recommend using the all so incredible 4x4 Interval Workout. Here is how:

If you follow these 4 simple steps, 3-4 times a week, your endurance will be adequately increased within 6 weeks. Step 1: warm up! Slow jogging with aprox. 60% of max pulse. (10 minutes) Step 2: increased speed with 85-95% of max pulse. If you do not have pulse-watch, you may know you're doingnitnright when you absolutely don't want to talk when running. (1-2 minutes) Step 3: active recovery. Slow phased jogging (as in step 1). (3 minutes) Step 4: repeat step 2 and 3 4 times.

Good luck with your cardio!


If you want "to be able to run for longer amounts of time without taking a break," you should be jogging/running at least 30 minutes continuously at a pace that is comfortable enough that you can still speak short sentences. Only walk if necessary, and even then try to keep the break under a minute. The sprinting intervals other answers are recommending will help you mostly with speed and anaerobic fitness. Going from no running to interval training, they will still help a bit with endurance, but not nearly as much as steady, consistent running for longer periods of time. It's all "cardio," but running for longer without breaks means focusing on aerobic fitness and muscular endurance. Simply putting in the miles should do that just fine. Throw in a couple of interval workouts and you'll be feeling much more fit in a matter of months.


I wish I had some sort of study to back this up but I read on a news site somewhere that sprinting in a short amount of time can be comparable of not better than jogging for a longer amount of time. So if you prefer to only do a 10 minute sprint, this may work just as well as jogging continuously for 30min. I would suggest jogging at a comfortable pace for 30 min on one day, alternate with a sprint on the other, and then every week increase the speed of your jog and the duration of your sprint. In time and increasing levels of difficulty you will build endurance.

I can tell you that the American Heart Association recommends at least 30 minutes of moderate intensity excercise 5 times per week for heart health. In addition to heart health, you'll also reduce the risk of other conditions like strokes, diabetes, etc... So if you can only get 30 minutes in and you continuously jog that duration you'll be helping your body out tremendously vs not excercising at all.

  • Nice answer, but please use full forms. AHA is American Heart Association, isn't it? I am from India, I didn't know till I googled it.
    – Freakyuser
    May 1, 2013 at 15:32

To improve cardio any fitness level you should run at a pace that is just faster than where it is still comfortable to talk as you run. It is also about technique, you should not tense your shoulders (they should be controlled but loose) and make sure that your arms do not cross the center of your body as you run because this is a very inefficient way to run. Keep your feet facing forward and your arms bent at a 90 degree angle. All this information has been sourced from varying places, including a friend who was a fitness specialist for years and personal experience. Ultimately make sure that you are comfortable (not too comfortable!) when you run.

Another alternative to running for ages is interval training (shorter, more intense training periods) if you don't have heaps of time spare. I'm not too sure about what is best for what fitness level, and this improves anaerobic fitness rather than aerobic fitness, but there are a range of varying excercises that you can do that are easy to find with googles help.

Any cardio is better than no cardio. Never push TOO hard! Hopefully this is helpful.

  • Telling someone to google something is not useful, why don't you provide some exemplary exercises?
    – Baarn
    Jun 30, 2013 at 9:02

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