I'm a 27 years old man, I'm 1.76m tall, I weigh 66 kilos and I have 6.6% body fat.

My current goal is to improve my posture and my muscular mass. I think I have a pretty good heart health (I have a resting heart rate of 50-56 bpm, and >I usually hit 140-150 bpm at elliptic bike/fixed rower and 160 bpm at SkiErg).

I currently do two cardio workouts of 20 minutes per week.

My thought is the following: since cardio and muscle growth "consum" fat, regarding my low body fat, does cardio slow down my muscle growth? If so, should I stop doing cardio workouts?


3 Answers 3


Cardio doesn’t consume fat, muscle, bone, or otherwise. Cardio, like any activity consumes calories and depending on the type it may even help to sustain or potentially even build muscle.

The only thing that will make body weight lower or higher (this means both muscle and fat) is your nutrition. Your activities simply determine the shape your body adapts to.

Should you stop doing cardio? I can’t imagine there being health benefits to doing so. If you are worried about losing more bodyfat, you simply need to eat more to compensate.

  • I definitely agree with the conclusion and also agree for this post's sake that 40min of cardio won't have much effect on his individual body weight. However, I'd say while nutrition is by a good measure the most significant factor in losing weight you can't say it's the "only thing". It's said in the first sentence that cardio consumes calories and may potentially build muscle, then in the next says nutrition is the only thing that can make muscle and fat higher and lower.
    – Matt Sides
    Commented Jun 19, 2018 at 13:16
  • Nutrition determines size while activities determine shape. I mention that cardio can -help- to build/sustain muscle, because as an activity it determines shape. Nutrition on the other hand will determine size, gaining/losing fat, gaining/losing muscle. It's an interwoven relationship, if your activities are that of a couch potato and you eat in a caloric surplus your shape will adapt to that and the weight you gain will be mostly fat. On the other hand, if your activities are that of an olympic power lifter, those extra calories will add a lot of muscle weight. Commented Jun 19, 2018 at 13:30
  • Okay I see what you're getting at, I agree there. Not saying you're implying this necessarily but I'd say it's not a one to one relationship between muscle and fat. For example if I kept my diet like it is now but started training like Phelps or ran a marathon every day (I mean I'd be dead if I tried that but in theory) I'd lose more fat and muscle then I'd be gaining in muscle. The number on my scale would go down.
    – Matt Sides
    Commented Jun 19, 2018 at 13:48

Assuming you are not playing any sport that requires extra conditioning (cardio), and that you can carry bag of groceries over flight of stairs and not die -- you don't need extra cardio, and your current routine is too much already. I suggest you read this for more info

Try to see this from a cost/benefit point of view, where cost is generally non-refundable time spend on the gym. As the other answer points, cardio consumes calories and time, and doesn't build any new muscle tissue. From your goals it seems you want more muscle. Thus, I guess that time you spend doing 2 cardio sessions could be better spend building muscle through weight lifting.

  • 1
    40 minutes of cardio a week is fairly minimal. Everyone should get their heart rate up for at least 40 minutes right? Commented Jun 17, 2018 at 20:49
  • @DanBeaulieu How do you know that to be true? Commented Jun 17, 2018 at 20:51
  • @DanBeaulieu please cite that science. Or read the article i linked above (written by actual MD/weightlifter/coach). Commented Jun 17, 2018 at 20:58
  • 2
    That site has an agenda, it is heavily biased towards power lifting. The article you linked explicitly mentions goals, we do not not the OPs goals. If they want to increase muscle mass or strength, then the article you linked is valid. If the OP wants to improve how long they can run/cycle etc for, then a more cardio regime is valid. For general fitness, find a balance between strength and cardio. Also remember variation is a good things. You avoid issues of adaption and boredom.
    – Jon P
    Commented Jun 18, 2018 at 6:37
  • @JonP “My current goal is to improve my posture and my muscular mass.” Commented Jun 18, 2018 at 14:26

I'm 185.5cm tall and weigh about 96kg. I do three intense cardio workouts every eight days (two running [3.5 miles and 4.5 miles], one bike or stationary bike [20min time trial]). This doesn't interfere with muscle or strength building at all for me. I've been making multiple weightlifting PRs (I do about 8 different lifts every workout) every time I go to the gym for the last eight months (ever since I started taking 5grams of creatine a day). So two intense cardio workouts a week definitely will not interfere with muscle/strength gains. You just need to get enough protein, carbs, fat, etc.

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