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Metabolic conditioning: what it is and how it can improve your fitness

Metabolic conditioning optimizes the body's ability to produce and utilize energy during training. This type of workout may significantly improve your body composition and performance.

When it comes to fitness, metabolic conditioning has often been conflated with high-intensity interval training (HIIT). Touted as a revolutionary method for rapid weight loss and performance enhancement, metabolic conditioning does indeed offer these benefits. However, its core objective goes beyond that—it aims to optimize your body’s ability to generate and use energy effectively during exercise. When executed correctly, metabolic conditioning can serve as a catalyst to significantly enhance your fitness regimen.

Different energy systems

The energy you get from food is converted in your muscles to adenosine triphosphate (ATP) which is used to fuel physical activity. The body employs 3 distinct pathways to produce this energy: the phosphagen, anaerobic, and aerobic systems.


The phosphagen system (immediate energy pathways) relies on the small reserves of ATP already present in your muscles, offering an intense burst of energy but only for 8-10 seconds. This is the primary energy source for activities like 100-meter sprints.


When immediate ATP stores are depleted, the body switches to the anaerobic glycolytic energy system, converting muscle-stored glycogen to ATP. This can fuel high-intensity work for approximately 120-180 seconds and is commonly used in HIIT and 400-meter swim intervals.


The aerobic system (long-term energy pathways) requires oxygen to create a sustained chemical reaction with glycogen and blood glucose, providing a steady flow of energy for extended activities like long-distance running.


Metabolic conditioning aims to enhance the efficiency of all these energy pathways. While it can technically be applied to weightlifting, HIIT, and endurance marathons, the term “metcon” (metabolic conditioning) most frequently refers to high-intensity, all-out workouts that train the immediate and intermediate energy pathways.

What is metabolic conditioning?

A metabolic conditioning workout hones in on a specific energy system, triggering it repeatedly to maximize its efficiency. This brings about adaptive changes in the body, such as elevated heart rate, increased ventilatory rate, improved blood flow, or elevated post-exercise oxygen consumption (EPOC). This means your muscular, cardiovascular, and respiratory systems are trained to perform either more work in less time or to operate at peak capacity for extended periods. The outcome is that your body becomes adept at generating and using energy more effectively during exercise.

Benefits of metabolic conditioning

Metabolic conditioning has numerous health benefits.


Positive impact on body composition and metabolism 


By enhancing the functionality of your body’s energy pathways, metabolic conditioning helps reshape your body composition and metabolism. High-intensity training can elevate your EPOC, allowing you to burn more calories for several hours post-workout. Studies show that a single session of high-intensity resistance exercise can even temporarily boost your basal metabolic rate for up to 48 hours. If you perform this type of workout on a regular basis, metabolic changes become more consistent. A study has shown a significant increase in basal metabolic rate in sedentary adult women after 6 weeks of moderate functional resistance training.


Athletic performance and endurance 


Metabolic conditioning is also an invaluable asset in preparing for sporting events or endurance marathons. It fine-tunes your aerobic fitness, or the measure of how efficiently you can utilize oxygen during exercise.


In 2018, the first longitudinal research observed changes in body composition and performance after 16 weeks of high-intensity functional training in men and women. According to the results, a metabolic conditioning program reduces body fat without decreasing total body mass. Researchers noted skeletal improvements in the trunk and lower limb area associated with greater bone mineral density. Study participants increased performance in all workout challenges.

Metabolic conditioning has numerous health benefits including a positive impact on body composition and metabolism.

High-intensity interval training and metabolic conditioning

Although often used interchangeably, HIIT and metabolic conditioning are not identical. Metcon encompasses a broader range of activities, including but not limited to HIIT, such as weightlifting, sprint interval training (SIT), circuit training, and CrossFit.


HIIT workouts are performed at 80-95% intensity. Metcon exercise intensity varies depending on the fitness goals: it can require maximal or supra-maximal intensity for immediate pathways or can be performed at moderate intensity if you focus on muscular endurance.

How to structure your metabolic conditioning workout

To gain the most from your metabolic conditioning workout, it’s essential to focus on one specific energy pathway. This means structuring your exercise-to-rest ratio accordingly.


A ratio of 1:12 or 1:20 targets your phosphagen system. It is used in sprint interval training: for example, a 10-second all-out sprint with a 2-minute rest afterward. A ratio between 1:2 and 1:6 is the most common for HIIT and strength training targeting anaerobic systems. For example, you can repeat a bodyweight exercise for 1 minute, then rest for 2 minutes. Tabata protocol uses a 2:1 ratio (20 seconds of exercise followed by a 10-second rest). These exercises are usually performed at a smaller intensity than in SIT. Finally, low-intensity aerobic exercises targeting long-term pathways are performed at a ratio of 1:1 to 1:3.


Another popular form of metcon workouts—metcon circuit training—typically includes a set of 5-10 exercises targeting all major muscle groups done with minimal rest in between.


Metabolic conditioning programs can use 2 types of workouts: AMRAP and EMOM.


AMRAP stands for As Many Rounds As Possible. This means that you have to do as many exercise repetitions as you can during a predefined period of time.


During an EMOM (Every Minute On the Minute) session, you complete a predetermined amount of exercise repetitions in 1 minute. Once finished, you can rest for the rest of the minute before moving to the next exercise. As your fitness level improves, you are able to complete the work faster and get more rest.


As you progress, you can modify your metabolic conditioning program in multiple ways:

  • Increase the number of intervals.
  • Raise the intensity.
  • Do longer intervals at the same intensity.
  • Reduce the rest periods.

Example of a metabolic conditioning workout

Here is an example of a metcon workout for an intermediate level that targets intermediate pathways:


5 mins – Warm up

30 secs – All-out sprint on CAROL Bike

30 secs – Plank

30 secs – Lunges

30 secs – Burpees

3 mins – Rest

Repeat 5 rounds.

REHIT—a science-based alternative to metcon workout

Reduced Exertion HIIT (REHIT) was developed in collaboration with leading exercise researchers to create the shortest, most effective workouts. REHIT creates the most potent training stimulus with just 2×20-second sprints. It’s scientifically proven to deliver superior health and fitness benefits compared to regular cardio exercise in 90% less the time. 


CAROL Bike is the only bike fully optimized for REHIT— making it simple, effective, and safe. CAROL’s AI-personalization tailors the workout to you and helps you push to your limits during the sprints. Like in a ‘fight or flight’ situation, your muscles are forced to mobilize about 25-30% of muscular glycogen—your emergency energy reserve—releasing key signaling molecules (AMPK and PGC-1a), telling your body it must get fitter and stronger. 


You develop more mitochondria, your blood plasma volume increases, and your heart gets stronger. Resulting in increased aerobic and anaerobic capacity. 

REHIT allows you to burn more calories on a 15-minute CAROL ride, than a 30-minute run, and improve your VO2max by 12% in just 8 weeks.


The 5-minute REHIT workout has the following structure:

  • 20 seconds – 2 mins – Warm-up
  • 20 seconds – All-out sprint
  • 1-3 mins – Recovery
  • 20 seconds – All-out sprint
  • 3 mins – Cooldown

CAROL Bike is scientifically proven to deliver superior health and fitness benefits compared to regular cardio exercise in 90% less the time.

Avoid overtraining

Metabolic conditioning workouts are very taxing, putting the body under a lot of stress. Given that overexertion is the most common injury reason in fitness, they may put you at a higher risk.


High-intensity metcon workouts shouldn’t last more than 35 minutes (excluding a warmup and cooldown), according to the National Exercise & Sports Trainers Association. Beginners should start with a 20-minute workout. You can include 10-15 minutes of metabolic conditioning exercises at the end of your regular training session. It’s important to gradually increase the intensity and avoid overtraining. 1-2 metcon workouts per week are enough even for advanced athletes.


Metabolic conditioning is a powerful strategy for accelerating your journey toward achieving your fitness goals. It offers a robust framework for enhancing athletic performance, promoting fat loss, and increasing muscle mass. Adopting a well-structured metabolic conditioning program can dramatically transform your exercise efficiency and overall well-being.

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