Cardio Adaptation: A Big Fat Problem?

Tracy Bodner
by Tom Venuto

QUESTION: Tom, I think I’m experiencing cardio adaptation. In order to reach the same heart rate this week, I have to exert myself more than last week. This is leading to a week-to-week trend of progressive intensity, difficulty, etc. I’m wondering if this means I’m burning fewer calories and if this is going to eventually make me plateau and I’ll have to do tons of cardio just to maintain. Or, is cardio adaptation really a non-issue? I keep hearing different opinions on this. Can you help?

ANSWER: Congratulations for getting in better and better condition! That’s what adaptation is. The more you train, the more efficient you get at doing the workouts, until you need a more challenging workout to keep improving. But adaptation is not something to panic about. Chasing progression is actually what makes this a fun, lifelong endeavor.

Your body adapts every which way from here to Sunday, in every bodily homeostatic system. Outside a few extremes (which I’ll mention below), it’s normal, and cardio adaptation as it relates to fat loss is mostly a non issue because adaptation to a training stimulus and metabolic adaptation to a deficit are not exactly the same thing.

Does cardio training make your body more efficient? Sure. Does your calorie expenditure go down as you lose weight? Yep. Do these things contribute at least in part to the slowdown of fat loss or in some cases to plateau? It can.

However, in no way does this suggest that cardio becomes fruitless for fat loss after doing it for a while or that you’ll have to do hours of it just to maintain. The fact is, you’re always burning plenty of calories with vigorous cardio, even if you’re burning somewhat fewer than you were when you were heavier / fatter and or unfit. All those calories burned help with the deficit you need for fat loss.

That leads us to the first secret:

One way you overcome any shrinking deficit is with progression.

For example, you might start your fat loss phase with 3 or 4 days of cardio and you progressively increase the frequency. You might start with 30 minutes and you progressively increase your duration. You might start at an intensity level of a 6 perceived
exertion, and you progressively ratchet that up too.

Your concern – and many others share it – is whether eventually you plateau, even though you are maxed out on cardio. Well, it might seem that way, but remember, you’re going to reach your body fat % goal in weeks or months and then you no longer need so much cardio – you can cycle back from a fat loss cardio program to a maintenance cardio program.

And that leads us to the second cardio secret:

Cardio periodization (aka cardio cycling).

Competitive bodybuilders and fitness models are the true masters of peaking their physiques for a deadline and doing it better and better, year after year, throughout their careers. Cardio periodization is one of their secrets.

There’s a maintenance phase (athletes sometimes call it an off season) and a peaking phase (the pre-contest season). During the maintenance phase, you do less cardio and during the fat loss or peaking phase you do more. Then you cycle back to maintenance.
With each successive peaking phase, you shoot for a new all-time best condition.

You don’t have to be a bodybuilder to use this strategy. Once you’ve achieved your target weight and body fat level, slowly downshift into a maintenance phase level of cardio. Once or twice a year, if you want a challenge, ramp it up again and go for a personal best again.

In the weightlifting world, cycling intensity, volume and other training variables is known as periodization. Why more people don’t apply this concept to cardio training is a mystery to me. Doing hard cardio for hours every day or seven days a week, month after month, year after year, is unnecessary and may lead to overuse injury, suppressed immunity, overtraining and burnout.

Endurance athletes can thrive on higher sustained training volumes because they eat so much to support the training. And like all smart athletes, they also use periodization.

Slashing calories and carbs and trying to do hours of cardio a day under that kind of energy restriction is where problems usually occur, but some people never scale back on cardio and frankly… THEY ARE AFRAID TO EAT! This is especially common with
female physique athletes, as well as aerobics instructors who teach multiple classes a day.

This is the area that can be a big problem. It’s the adaptive response that takes place when people starve themselves on low calories or low carbs, AND at the same time, go nuts with cardio – double cardios, 90 minutes, 120 minutes or MORE (I’m not exagerrating – I’ve seen figure athletes claim to do 2 to 3 hrs a day), every day, and when the PROS do it,
amateurs emulate.

Metabolism decreases with dieting and weight loss – but it happens in two ways – you adapt as you lose weight (lighter body needs fewer calories) and there is the adaptive thermogenesis part – the decrease in calories burned that’s NOT accounted for by the
weight loss alone (aka “starvation response”)

Well check this out: It turns out that this adaptive thermogenesis is MUCH WORSE when you’re starving AND trying to do tons of cardio. This has been verified in the research such as the study from the University of Vermont that was published in the Journal, Sports Medicine. The author made this alarming conclusion:

“It appears that the combination of a large quantity of aerobic exercise with a very low calorie diet may actually accelerate the decline in resting metabolic rate.”

Starvation diet plus tons of cardio is like shooting yourself in the foot because you’re slashing calories so hard and training cardio so hard, yet you’re slowing your metabolism. Therefore, your deficit is not as large as you thought it would be, and meanwhile you’re beating yourself into the ground.

The lessons here?

Well first of all, you have to eat! You have to Feed the Muscle! You have to eat appropriately for the type of training you’re doing.

You can sometimes get away with fairly extreme diets when you’re not that active – especially if you’re lifting weights at least a few times per week and your diet is high in

Or, you can get away with extremely high amounts of cardio, if you’re eating a lot, like what good endurance athletes do…

But starvation combined with a huge amount of cardio appears to be very very bad news. It’s a big problem in female physique sports, especially. Yeah, they get ripped and even win titles – but at what cost – and are they struggling with rebound weight gain, and making the peaking process actually more difficult each time? Or worse – damaging their health or developing eating disorders?

You have to find the balance in the middle… the right amount of calories burned, balanced with the right amount of calories reduced from food intake, in a way that’s practical so you can actually execute the plan and stick with it, and in a way that’s physiologically friendly to your body (doesn’t zap your metabolism, chew up muscle and reduce fat-burning hormones).

The most recent edition of Burn the Fat, Feed the Muscle (BFFM) teaches you EXACTLY how to do this – including the 8 strategies to keep you out of starvation mode, as well as how to cycle calories, carbs and cardio throughout the year to BEAT adaptation and keep making steady progress…

About Fitness Author and Fat Loss Coach, Tom Venuto

Tom Venuto is the author of the #1 best seller, Burn the Fat, Feed the Muscle: Fat Burning Secrets of the World’s Best Bodybuilders and Fitness Models. Tom is a lifetime natural bodybuilder and fat loss expert who achieved an astonishing ripped 3.7% body fat level without drugs or supplements. Discover how to increase your metabolism, burn stubborn body fat and find out which foods burn fat and which foods turn to fat by visiting the home page at: