I’m a big cardio advocate. I especially love walking and running for my lower body and boxing for my upper body. 

Cardio helps me get into shape, keeps me lean and it’s fun :)

But over the years, a lot of you guys asked me if running is really good for you, so I wanted to answer that question in this blog post.

Yes, running is a great exercise and, depending on your goals, it can be an awesome way for you to get in shape! 

Let’s take a look at why, how, and what you need to know.

is running good for you


YES! Running burns a TON of calories!

But the amount you burn depends on two things:

  • your weight
  • your pace

The more you weigh, the more calories you’ll burn. This is because you’re moving more mass with each step.

As you lose weight, you’ll lose fat and that will end up making you burn fewer calories during your workout. The smaller you are, the less calories you burn (increasing muscle mass can increase the calories you burn).

Don’t panic! It’s not a bad thing! It just means you need to change things up. Like adjusting your speed.

The faster you run, the more calories you’ll burn

And if you really want to push things, you can add interval running. This will help you burn more calories.

Keep in mind that if you tend to bulk up easily (and adding a lot of muscle isn’t one of your fitness goals), you’ll want to stick with steady state running.

Also, keep in mind that running uphill will build more leg muscle than running on a flat surface.

running burns lots of calories


Okay, so this where I need to get a bit technical :)

When we exercise, our bodies create energy in two basic ways:

  • aerobically (with oxygen) – FAT burning zone
  • anaerobically (without oxygen) 

To put it simply, when you’re in the aerobic zone, your body will burn FAT. And when you’re in the anaerobic zone, your body will burn carbs.

Your body will use the anaerobic pathway for:

  • High-intensity exercise (including high-intensity cardio such as running)
  • Weight training
  • Interval training

So typically, your body will actually burn carbs when you are running. BUT, the fitter you are, the longer you can keep your body in the fat burning zone when running. 

This is known as the anaerobic threshold: the point at which your body switches from the aerobic to anaerobic pathway. 

When you build up cardiovascular health, your anaerobic threshold gets harder to reach. You’ll stay in the aerobic zone  longer.

Running increases your cardiovascular fitness and  your anaerobic threshold. 

This means that you can exercise longer and at a higher intensity in the aerobic “fat burning” zone and as a result, burn more fat.

I’ve written in more detail about this in these blog posts:



does running burn fat


The long and the short of it is, running is a GREAT way to lose weight and fat. And interval running is especially great for increasing your anaerobic threshold to help you burn fat longer. 

But it depends on your body type. If you bulk up quickly, interval running can build bulk your legs. 

Not sure what your body type is or how you typically build muscle? Take my body type quiz and find out more!


Running does a lot of good. It helps you burn calories, improve your cardiovascular health, and keeps you lean. 

But is it good for toning your legs?

The answer is a little bit complicated. Running can build muscle. And for some people, this will result in toned and defined leg muscles. 

But for some women, running can cause our legs to bulk up, especially for endomorph body type.

That doesn’t mean you should give up running. You just need to be selective about how you do it. 

Remember when I mentioned running on flat surfaces? Stick to it! It’s the BEST way to avoid building unwanted muscle.

how to get lean and toned legs



I know that a lot of personal trainers now prefer weight lifting over cardio but I think that a well balanced fitness routine should have both. 

If all you do is running, you will be slim but you won’t have nice muscle tone. Both running and resistance training are important so make sure your workout program includes both.


The best way to get in shape and start burning fat is to ease into it. I know…you want to start shedding those pounds but you can’t push yourself too hard too fast.

If you do, you run the risk of injuring yourself, and you’re more likely to give up. Pain has a way of destroying your ability and motivation to get fit and get lean. 

You’ll feel sore. That’s normal. But the soreness shouldn’t be so severe that you can’t go about your normal day. Take a rest day and reevaluate. 


Stretch your muscles out and take an extra active recovery day and see if the soreness goes away. 

This can make all the difference in your recovery and keep you motivated and ready to run at your best.  


Rachael xx

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Rachael is an Australian born certified personal trainer and nutritionist who holds a Bachelor degree in Science.

After struggling for years to find an exercise and diet program that is tailored to women striving for lean and toned body with no bulk she designed her Lean Legs Program. This program is tailored to each body type and focused on helping women get toned but feminine bodies, without getting bulky.

Her mission is to empower women and help them stay in shape in a healthy and balanced way.

8 Responses

  1. Hello Rachael!!
    First i justo wanted to thank you for this amazing program, it has allowed me to retch my goals and feel the most comfortable with myself yet.
    So, i run about 3 days a week, and do around 6-8Km in 40-50min per day, but if one day i wanted to slim my legs again what would be the running/ walking racius a week for me to see results?
    Thank you a lot!!!

    1. Hi lovely,

      Thanks for reaching out!

      If your goal is to slim down your legs, there are 3 steps you should follow – do the right type of cardio, do bodyweight resistance training, and adjust your diet for weight loss.
      I have a very detailed blog post that will help you learn how to slim down your legs so please go give it a read

      It will definitely help! :)

    1. Hi lovely,

      Running and power walking are both great cardio for burning calories and losing fat. Running is a type of high-intensity cardio that actually builds muscle so it’s not recommended for some women especially endomorphs. Power walking is light-intensity cardio where you walk at a faster speed than normal.

      There’s also a difference in the motion that you use. Running engages your quads a lot and can cause unwanted bulkiness while power walks won’t cause bulkiness at all.

      If you need more help or tips, feel free to email us at


  2. Hi, Rachel! I just started the program. I’m a endomorph. I’m used to heavy functional training that resulted in unwanted muscle and I feel very unconfortable… I’m used to run 5-6km in a flat surface… Would that add muscle to my legs? Or should I avoid so many km? Thanks in advanced!

    1. Hey lovely,

      Thanks for reaching out! :)

      It is so exciting that you are starting this fitness journey! :)

      It would be best to track the appearance of your legs for a couple of weeks and see how it affects your legs.
      Some girls benefit greatly from running while others tend to bulk up from it.

      If you notice them bulking up, it would be best to swap running with more power walking.
      Rachael recommends doubling up on the time invested – e.g. if the run was supposed to be 20 minutes long, make sure that you do a 40 minute power walk instead. :)
      Also, make sure that you do it on a flat surface to avoid any chances of bulking up due to the incline. :)

      If you have any other questions feel free to contact and we’ll gladly help. :) xx


  3. Hey Rachael – How can we know whether running is bulking our legs? I can’t tell if I’m just a bit of a worrier. I’m a mesomorph. I’ve been walking (unfortunately my neighborhood is a little hilly, so try to be flat but it isn’t always) and doing your workouts, and I’m definitely slimming overall, but I really do want to keep making my legs smaller! Thank you!

    1. Hey lovely,

      As a mesomorph, it could bulk you up but doesn’t have to! So just make sure that you track your legs appearance.
      You can do that by measuring them or taking pics every 2 – 3 weeks.

      It’s great that you are slimming down!
      Enjoy our fitness journey! xx


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