Exercise Intensity and Your Metabolism

Woman exercising intensely to increase her metabolism.


So you’re working out but are you working out hard enough? I’ve been guilty of going through the motions while still hoping for results that I didn’t deserve. Intensity is one of the most important factors in your workouts for strength, for power, for endurance and for your metabolism. As you read this article, take a minute think about your current workouts and your current effort level. Are you really working intensely enough?

Research now shows that, on average, folks experience a 2-4% decline in their resting metabolic rate with each passing decade after the age of 25. Add to this metabolic decline a 5lb loss of muscle mass with every decade and getting older is a depressing proposition.

When it comes to metabolism and muscle preserving strategiesintense exercise is the king. With it, you get to keep that muscle mass and fuel your metabolism. Without it, you get to politely smile while you wave bye-bye to your youth, muscle strength, lean mass, and metabolic rate.



Certain types of exercises aren’t always the catalyst to intensity. It’s how hard you’re working. That being said, here are some ideas for workouts that can get you into a more intense zone!

Certainly resistance training (strength training) is one of the biggies. However, there are a host of other types. Here are a few:

  • Interval running, cycling, rowing or climbing

  • Resistance circuits

  • Bodyweight circuits

  • Rope jumping

  • Running hills

  • Burpees, jumping jacks (plyometrics)

  • Medicine ball slams, tosses and throws

  • Kettlebell exercises

  • Tire flipping, fireman carries, farmers walking, other strongman activities

Basically, any physically demanding task that a) incorporates many muscle groups and b) is done near your maximum heart rate qualifies. So feel free to invent your own form of intense exercise.



When you do an intense bout of exercise, you overload your muscles. This overload helps stimulate protein turnover, protein building, and gains in lean mass (or at least lean mass preservation). But what about the cardiovascular system?

Well, with all those muscles doing so much work, the cardiovascular system MUST respond by pumping blood faster and delivering a lot of oxygen to your working muscles. So you definitely get a cardiovascular benefit from doing intense exercise.

In addition, your metabolic rate also benefits from the increased oxygen consumption.

You see, the more muscle you have and the more exercise you do, the more oxygen your body will need. As oxygen generates 5kcal per liter consumed, a high oxygen demand means that your body is burning a ton of calories.


The “After Burn”

The real key to intense exercise is what happens AFTER your exercise session.

If your exercise is intense enough, your oxygen demand remains elevated for well after the exercise session.  With low intensity cardio, you only benefit from a few minutes of additional oxygen demand (and metabolic activity).

However, with high intensity activity, the oxygen demand can remain high for anywhere from 6 hours to 48 hours, depending on the intensity and duration of the exercise session. And remember, a bigger oxygen demand means more calories burned. So it’s only your high intensity activity that boosts your metabolism 24-7.

So, with intense exercise, more oxygen is being consumed (and energy being used) during the exercise, after the exercise, and pretty much all day long.

Interestingly, you burn a lot of fat too, during this post-exercise period. During high intensity exercise, the rate of fat breakdown is high also high.

Beyond fat burning, when you do high intensity activity regularly, additional muscle will be developed. This creates an even further metabolic demand for the body and more energy is utilized for normal daily activities, even at rest.

So, make no mistake, if you want to avoid becoming another metabolic slowdown or obesity statistic, the bulk of your exercise should be of the high intensity kind. Notice, we said the “bulk” of your exercise should be high intensity. This means that there is a place for lower intensity exercise (walking, dynamic stretching, etc) too but the majority should be higher intensity.

So, now that you know, go out there and get your high intensity exercise in! We’ve got a workout for you below to accomplish just that!


High Intensity Workout

Grab an exercise mat, a timer and a water bottle and get set for this workout!

Warm up 3 – 7 minutes (or as much as your body needs)

Squat Jumps – 30 seconds
Active Rest – 20 seconds (active recovery – march, step touch, etc)
Burpees – 30 seconds
Active Rest – 20 seconds (active recovery – march, step touch, etc)
Ski Jumps – 30 seconds
Active Rest – 20 seconds (active recovery – march, step touch, etc)
Sprint – 30 seconds – 1 minute
Active Rest – 20 seconds (active recovery – march, step touch, etc)
*Repeat circuit 3 – 5 times.

Cool down 3 – 7 minutes (or as much as your body needs)



Intensity is necessary, at points, in your workouts in order to facilitate change and an elevated metabolism. I know many of you reading this are thinking you can’t engage in high intensity because you don’t want high impact. Intensity doesn’t necessarily mean high impact though. There are ways to challenge yourself without jumping and jarring.

If you’re unsure of how to add intensity into your workouts, join us for a fitness retreat or sign up for our online personal training to get the guidance and motivation you need to reach your goals.

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