How Does Running Change Your body?

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Most people know that exercise can help them become healthier and look better. How will running specifically change your body?

Running is a well-known type of recreation that certainly increases your movement intensity to levels considered to be exercise. If you go from not doing many workouts to running more often you will definitely notice some changes to your body sooner or later.

There are of course no guarantees. For example for people who don’t exercise often, running may help them tone their legs. On the other hand people who do leg strength training exercises will not see as much muscle building from running.

That being said, many people will see their body change in the following ways when they start running more.

1. You may lose body fat

Running, even at low speeds, is likely a more intense movement than the other movements you do throughout the day. By increasing the intensity of your movements for a period of time you use up more energy than usual.

What happens next depends on how much energy from food is coming in.

If there is more energy, measured in calories, coming in from food than you are using throughout they day you will still gain energy stores, likely body fat. Even when this is the case running would make it so you gain less body fat compared to if you did not run.

If there is as much energy coming in to your body as there is going out your body’s energy stores will stay more or less the same.

If you are using more energy than is coming in from food you will start using up energy stores like body fat. If this is already the case without running, adding running can speed up the process even more.

In simple words running can help you lose weight but only if other lifestyle areas like your diet are on point.

What areas your body will use stored fat from first is generally not something you can choose. An area like your belly is usually one of the last places where you will lose body fat.

30 minutes of running at 5.2 mph (8.4 kmh) can help you burn around 266-457+ calories depending on weight, intensity, and much more. If you want to learn how to burn more calories while running make sure you read the article on how many calories running burns.

Doing a workout at high intensity can also cause something called “afterburn”. This is basically having an increased metabolism for a while after you stop doing the exercise.

2. Your muscles may become stronger

While running is mainly a cardio exercise, which means that it mostly focuses on your cardiovascular system, this workout can also help you build some muscle in other areas.

This is mostly the case for workout beginners and people who don’t lift any weights. Someone who already regularly does squats with his or her body weight on their shoulders in extra weights will likely not tone that much, if any, muscle with running.

That being said if running can help you with this, extra muscle is not only beneficial for your health in many ways but it is also considered to be visually appealing.

Some of the muscles you engage with running include:

  • Calves
  • Glutes
  • Quadriceps
  • Hamstrings
  • Core

In simple words running may tone your legs, but, and even your stomach a small amount.

If you like the idea of toning your body while running you can do it with weights like a heavy backpack, weighted wristband, weighted ankle bands, or a weighted vest to increase the amount of muscle mass you gain.

If you are serious about building muscle you do generally want to choose weight lifting exercises over running. Especially if you are interested in building muscle in your upper body too.

3. Your body’s immune system may become stronger

Your immune system is a collection of biological processes that protects you from diseases.

On top of the many other changes in your body, physical exercise like running can make your immune system stronger (1, 2, 3, 4, 5). This in turn helps you with being sick less often.

You do have to keep in mind that at some point working out can turn into overtraining which can weaken immune function. However, most people don’t come close to this point.

4. Your mood may improve

Most people are not always completely aware of it but the physical health of the human body has a big influence on the mood and thoughts of the individual.

Running doesn’t just help with this by improving general health. There are inevitably many different reasons involved but one reason why exercises like running benefit mental health is that they promote the release of endorphins, “feel-good” hormones in your body (6, 7, 8, 9, 10, 11).

Besides the actual physiological changes running will cause, you will likely also have positive feelings about having done something challenging that’s good for you.

5. Your cardiovascular health may improve

Your cardiovascular system is the circulatory system inside of your body and includes heart and blood vessels. These transport many types of important nutrients, oxygen, and waste throughout your body.

When you move more intensely your body needs to transport these things, which means using your heart, at a higher rate.

Your heart is a muscle that can be trained by using it more intensely. By doing workouts like a running session you can strengthen your cardiovascular system which in turn leads to a wide variety of other benefits (12, 13, 14, 15, 16).

Do keep in mind that muscles can get injured. If you have not done any physical activity in a long time you may want to start out with low-intensity movements and build up from there. This means running at a low speed or even walking instead.

6. Your brain may work better

Another benefit of exercises like running is that they can help you improve your cognitive function in a few ways. First of all, they can help with the prevention of diseases like Alzheimer’s disease (17).

Another way working out benefits cognitive function is by improving brain plasticity (18, 19, 20). Better brain plasticity basically means that you are able to learn things faster, see the connection between things faster, and remember things better.

That means that adding a running workout to your routine can change your brain for the better and in turn benefit you by improving areas like your academic performance, job performance, and much more.

7. Your bones may become stronger

The next way running can change your body is by improving, or preventing degeneration of, your bone density, basically the strength of your bones (21, 22, 23, 24, 25, 26).

This is helpful for avoiding broken bones. Depending on your age you may not be that worried about something like this right now. However, exercising right now can help you avoid broken bones in 40 years. The things you do today have an impact on the future.

The way many parts of your body work is that by challenging them you set in motion processes that strengthen these body parts. The same goes for your bones, by putting pressure on them you make them stronger in the long-term.

Running is a great exercise for improving bone density. With other workouts like swimming, golf, and cycling you generally put less pressure on your bones than with running.

One study looked at the difference in bone mineral density between 60 cross-country runners and 47 non-running controls with similar age and BMI. As expected their findings suggest that running is beneficial for bone mineral density (27).

8. Running may lower your LDL

LDL, also known as low-density lipoproteins, is considered to be “bad” cholesterol since there are negative side effects associated with having high levels of LDL in your blood.

One of the things you can do to reduce the amount of LDL in your blood is doing workouts like running (28, 29, 30, 31).

9. Your lungs may become healthier

To move around your body needs oxygen, the more intensely the more oxygen. Your body absorbs oxygen from the air through your lungs.

By using your lungs more, thanks to workouts like running, you can improve how well they work (32, 33, 34, 35, 36). Generally the more intense your running workout the more it benefits your lung capacity.

Improving how well your lungs function leads to benefits like improved exercise performance and getting tired slower. If you are often out of breath because of walking the stairs running more often may help you avoid this.

10. Your body may age slower

Most people think of age as the number of days, months, and years that have passed since the day they were born, this is usually referred to as their chronological age. There are also many other ways to measure “age” based on physiological factors (37).

Exercises like running obviously won’t have an influence on the number of days that have passed since you were born. However, physical activity can slow down the aging in terms of how fast other measurement methods progress (38, 39, 40, 41, 42, 43).

In general these other age measurements are more accurate methods than chronological age for assessing risk on age-related diseases. Slowing these down can be a huge benefit for your health.

11. Your body is less likely to develop type 2 diabetes

Type 2 diabetes is a disease that involves consequences like high blood sugar, insulin resistance, and lack of insulin. These things in turn can have really bad consequences so type 2 diabetes is definitely something you want to avoid.

Exercises like running can help with preventing and getting rid of type 2 diabetes through a wide variety of internal processes in your body (44, 45, 46, 47, 48).

12. Your sleep may improve

Good quality and duration sleep are extremely important for your physical health and cognitive function. Unfortunately, many people can do a lot better with both quality and duration.

A lot of the things you do throughout the day influence the quality and duration in some way. One of the things that can benefit sleep a relatively high amount is doing a workout like running (49, 50, 51).

You do want to keep in mind that exercising too close to bedtime can have the reverse effect and mess with your sleep. Make sure you give your body time enough time to calm down after a workout. For most people this comes down to avoiding running at least an hour or two before going to sleep.

13. Your coordination and balance may improve

While the technique of running is not that complicated, you do need to use some coordination and balance. By using these more frequently you can get better at them like with most skills. Many people forget to implement balance training into their workout routine but it is a helpful fitness component.

The benefits of improved coordination and balance don’t just show up in other technical sports. Daily activities as simple as walking the stairs require coordination. By improving your balance falling becomes less likely.


While other workouts can also offer similar benefits, it is amazing that your body can change in such a great way from running.

One thing you need to remember is that running can be hard on body parts like knees and back, especially if you have a lot of pounds to lose.

In a situation like that, walking, the elliptical trainer, swimming, or other alternatives to running are likely better workout choices to start with.

If you feel pain in any body parts it may be a sign you are overdoing it. In that case, you may need some rest, better lifestyle habits, or a less intense running schedule.

Longer runs may require you to carry water while running and you want to prepare appropriately for weather circumstances like rain.

Also keep in mind that consistency is a big factor for a workout plan. The more you love the exercise you do the easier it becomes to do it consistently. If running is a workout you love, great. If not there are plenty of other exercises to consider that can also change your body for the better.

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Matt Claes founded Weight Loss Made Practical to help people get in shape and stay there after losing 37 pounds and learning the best of the best about weight loss, health, and longevity for over 4 years. Over these years he has become an expert in nutrition, exercise, and other physical health aspects.