How much cardio does it take to get into shape?

How Much Cardio You Should Do (and How Much Is Too Much)

The majority of people doing cardio are trying to lose weight. In fact, many think that you simply can’t lose weight without sacrificing sweat to the hamster wheels.

Unfortunately, research shows that just doing regular cardio guarantees little in the way of fat loss. In fact, many people wind up even fatter than when they began their cardio routines.

Well, I have good news for you: you can get–and stay–as lean as you want without ever doing more than an hour or two of cardio per week. 

In fact, if you want to achieve and maintain a low level of body fat while also preserving muscle, strength, and overall health, you can’t subject yourself to a torturous cardio routine. You must do less than you probably think necessary.

You have to work hard to burn a few hundred calories doing cardio, but you can eat them all back (and more) without even realizing it. A couple handful of nuts and a piece of fruit is all it takes.

The point here isn’t that the energy you burn doing cardio doesn’t support your weight loss efforts, but if you’re not also correctly regulating your food intake, you’re probably not going to reach your weight loss goals.

Your body adapts to the exercise to reduce caloric expenditure.

This is particularly sneaky and troublesome because while many people failing to lose weight can deduce or at least suspect they’re overeating, they’re completely unaware of this adaptive element of exercise.

The problem is simple: the more you do a certain type of activity, the more your body adapts to increase efficiency, and the more this occurs, the less energy is needed to continue doing it.

The net effect is people often think they’re burning more calories doing cardio than they actually are, eat more than they should to maintain an adequate calorie deficit, and then wonder if their metabolisms are just busted or if calorie counting simply doesn’t work.

Unwilling to give up, many then try to fight fire with fire by doing even more cardio, which does increase overall caloric expenditure but also brings the various health risks discussed earlier into play.

Cardio doesn’t preserve muscle, which is just as important as losing fat.

We instinctively say we want to lose weight, but what we really want to do is lose fat.

This distinction is important because losing weight includes losing muscle, which is to be expected when you combine a calorie deficit with cardio alone, and which is the road to a “skinny fat” physique.

The key here is the inclusion of resistance training in your weight loss regimen, which ensures that you lose maximal amounts of fat and minimal amounts of muscle.

So, as you can see, cardio is a double-edged sword of diminishing returns. A little bit of the right stuff can help you lose weight without compromising your health, but only if combined with a proper diet as well.

What, then, is the “right stuff” when it comes to cardio and weight loss?

Well, I’ve already mentioned that I do no more than a couple hours of cardio per week when dieting for fat loss, and I recommend the same for you, but there’s a bit more to my advice…

The Best Type of Cardio for Weight Loss

When it comes to losing fat, not all types of cardio are created equal.

The type of cardio you see most people doing is called low-intensity steady-state cardio, or LISS, and it  involves longer periods of low-intensity activity like walking, jogging, or biking.

LISS can help you lose fat but, as noted above, is very easy to out-eat and burns less and less energy over time. The reality is it’s just not a great way to spend your time if fat loss is your primary goal.

There’s another way to do your cardio, though, and it’s far more effective for losing fat. It’s called high-intensity interval training, or HIIT, and it involves alternating periods of high-intensity, all-out exertions and low-intensity “rest” periods.

Yes, HIIT is harder than LISS, but it’s also far more rewarding.

Studies such as those conducted by scientists at Laval UniversityEast Tennessee State UniversityBaylor College of Medicine, and the University of New South Wales have conclusively proven that shorter sessions of high-intensity cardio result in greater fat loss over time than longer, low-intensity sessions.

In fact, a study conducted by researchers at The University of Western Ontario showed that doing just 4 – 6 30-second sprints burns more fat over time than 60 minutes of incline treadmill walking. Yes, you read that correctly.

Research also shows that high-intensity interval cardio is particularly good for getting rid of stubborn abdominal fat, including the dangerous accumulations of visceral fat.

Although the exact mechanisms of how high-intensity cardio trumps steady-state cardio aren’t fully understood yet, scientists have isolated quite a few of the factors:

  • Increased resting metabolic rate for upwards of 24 hours after exercise.
  • Improved insulin sensitivity in the muscles.
  • Higher levels of fat oxidation in the muscles.
  • Significant spikes in growth hormone levels (which aid in fat loss) and catecholamine levels (chemicals your body produces to directly induce fat mobilization).
  • Post-exercise appetite suppression.
  • And more…

And as if all that wasn’t enough, keeping your cardio sessions shorter means you better preserve your muscle and strength, which is ideal for optimizing body composition.

Most fitness experts in the know don’t argue HIIT’s superiority in terms of fat loss but warn that it places a lot of strain on the nervous system and is likely to lead to overtraining.

Well, I’ve yet to find convincing evidence of this in the literature and have yet to run into that problem with my own body or the thousands of people I’ve worked with.

This is probably because I recommend a very moderate amount of high-intensity interval cardio–no more than 4 sessions per week, and no more than 25 to 30 minutes per session–and because the level of intensity found in studies used to support the overtraining hypotheses I’ve seen is quite a bit higher than the average person is even capable of (trained endurance athletes pushing themselves as hard as they possibly can).

Given all the above, I think it’s just a no-brainer to choose high-intensity interval cardio over low-intensity steady state.

The bottom line is 3 to 4 25-to-30-minute sessions of high-intensity interval cardio per week is you need to get as lean as you want.

Should You Do Cardio or Weights First?

We’ve covered a lot of ground already but I wanted to address this final point before signing off, and I’ll keep it short and simple.

Lift weights first and then do your cardio.

Heavy weightlifting requires a lot of energy, both muscular and systemic, and if you do cardio first–especially high-intensity cardio–your lifts will suffer.

The Bottom Line

Medicine has known the value of regular exercise for thousands of years but only recently have we gained a better understanding of how much is enough and how much is too much.

If you do at least a few hours of resistance training per week (and you should–it confers certain benefits you can’t get from cardio), you should view cardio as supportive, not essential, and you should do enough to reach your goals but not more.


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