How Does Running Physically Affect Your Body

There’s no doubt about it: running changes you. From an increase in endurance to the control over your body fat composition and heart health, running can help you become a happier, healthier, fitter individual. Let’s take a look at some of the physical effects of running and why, if you haven’t already, it’s time to get out there a give it a try.

Let’s explore how running changes your body both physically and mentally, as well as the positive and potential negative effects of running.

Immediate effects: what does running do to your body

When you run, numerous changes begin happening in your body from the moment you step out the door, throughout the exercise, and then for hours after you’ve finished.

To start with, your body releases chemicals (endorphins) that provide you with the energy you need to move. You’ll also notice that your body temperature rises, and you will start to sweat. Depending on your level of fitness, after a certain period, fatigue may you to slow down and you will want to stop. If you run fast and hard, lactic acid starts building up in your muscles, which can make it painful to keep going.

Post-run, you will feel energised, and your mood becomes elevated. This is because, during your run, the endorphins your brain releases for energy are still being released, so you get the so-called ‘runner’s high’.

As your body recovers from exercise, you’ll also be burning more calories than usual as you clear lactic acid and repair muscles – this is sometimes called ‘afterburn’. It can last for several hours – or even days, according to one study in a sports science journal.

What does running do for your body long-term?

If you go running regularly, you’ll start getting a runner’s body. This is pretty amazing! Your body is adjusting its shape and the location of muscle mass to suit your new hobby.

In many ways, the benefits of getting a runner’s body outweigh most of the disadvantages. Nonetheless, we’ve listed both the positives as well as some possible drawbacks of getting a running body.

Positive running effects on the body

Here are some of the key running benefits for body shape and general wellbeing:

1. You will have a healthier heart from running

Running is great for your heart. By running regularly, you lower your cholesterol and blood pressure levels, both of which are indicators of heart health. Running also helps you to lose or maintain weight. Being overweight puts a tremendous strain on your heart, so when you lighten the load, you reduce the stress on your body’s most important organ.

2. You will have a faster metabolism from running

Metabolism refers to the chemical process of burning calories. We all naturally have fast or slow metabolisms, which affect our body’s ability to burn calories or store them as fat. If you have a fast metabolic rate, you will burn more calories in a set time than you would if your metabolism were slower. The faster your metabolism, the less likely you are to accumulate fat. Running changes your body’s metabolism. The energy you expend while running helps you to increase the volume of calories burned. And the more intense the run, the longer your metabolism will stay ‘sped up’, even after your exercise is over.

 3. You will have more energy from running

Ever wonder why you feel energised after a great run? It’s a combination of physical factors that boost our energy in both the short and long term. First, when we run, our hearts pump, and this enhanced blood flow delivers more oxygen to muscles all over our body. Second, regular running leads to better cardiovascular stamina and reduces the demand on the lungs, enabling our body to use energy more efficiently. Third, running can help us get better sleep and rest, which leads to more energy during the day.

4. You will have stronger legs from running

Ever noticed a runner’s legs and seen how clearly defined the muscles are? When we run, we use all the muscles in our legs, big and small. If you are new to running, you might be surprised by how quickly you start to develop lean muscle in your legs and the speed at which you build endurance. It should be noted that if you are looking to add mass to your leg muscles, you should include weight training in your exercise routine and eat protein.

5. Your mind will become stronger from running

Another physical benefit of running is the effect on your brain. Not only will running keep you physically fit but it will also improve your cognitive abilities. According to the Alzheimer’s Society, a charity, numerous studies prove that regular exercise such as running can improve your memory and protect against future cognitive conditions, like dementia and Alzheimer’s disease. Running also increases the serotonin levels in your brain, fighting stress and generating a more positive way of looking at the world.

That’s why at ASICS, our philosophy is: “Sound body, sound mind”!

6. You’ll lose weight with your running body

One of the greatest benefits of running is that it helps you lose weight and body fat. Losing weight is fundamentally about using more calories than you consume. When you exercise, your body uses more calories than usual, so you will have a calorie deficit – over time that will mean you shed pounds as your body uses its own fat stores to provide energy instead.

Tracking calories? Download the ASICS Runkeeper ™ app which can help you accurately measure calories burnt when running, among other metrics.

7. You will get stronger bones too

It is well established that when you put stress on your bones, they become stronger and denser. That makes it less likely you’ll have injuries and makes your body more resilient.

8. You will notice various mental health benefits

Beyond what running does to your body, exercise also has a huge range of mental health benefits. Numerous studies have established that running can help tackle depression, anxiety and other mood disorders. More generally it can help reduce feelings of stress, and also lead to better sleep.

Read more: Discover the many benefits of running

Is running bad for you? Risks to be aware of

While developing a fit runner’s body is seen as a benefit for most, sometimes the effects of running on the body can go further than you might wish. Generally speaking, you can avoid most running body problems by resting enough, avoiding over-exertion and eating well.

1. Your muscle mass could reduce by running

This can be seen as a positive or a negative, depending on your goals. When we run, our body’s instincts kick in and it starts trying to rid itself of any unnecessary weight that might slow it down, and this includes muscle.

If you are running as part of a plan to lose fat while retaining muscle, then it’s important for you to consume sufficient protein to guard against the risk of muscle loss. Also,high-intensity interval training (HIIT) is a good way to train (i.e., shorter bursts such as sprints) to bring about fat loss without losing muscle.

2. Your chest could sag from running

For women, running can result in sagging breasts if you don’t wear the correct type of bra. No matter your size, choose a sports bra when you run to give your chest the right support, increase your comfort levels and reduce any chance of sagging.

3. You could experience knee pain from running

While the idea that running will damage your knees is largely a myth, it is important to take measures to reduce your chances of developing sore knees from your efforts. Build up your leg muscles, wear the correct footwear and maybe even opt for knee support in the form of straps or kneepads.

Unsure which shoes are right for you? Use our Shoe Finder.

4. Your toenails could go black from running

If you are increasing the amount of running you do, you could get a runner’s toenail, which is typically when the big nail of your toe goes black. While this is usually harmless, it can be unsightly. A runner’s toenail is mainly caused by microtrauma from wearing socks or shoes that are too tight. If your get black toenails, it might be time to invest in some new running socks or running shoes.

5. You could chafe when running

Chafing happens when the skin on one part of your body rubs against skin nearby or against clothing. It’s common on inner thighs, armpits, nipples and around bra straps. Good quality, breathable >running clothing will reduce the chances of chafing.

6. You could get blisters from running

Blisters are caused by friction when the skin on your feet rubs against your socks or shoes, and it’s more likely when your feet are hot or damp. To avoid getting blisters from running, you should choose specially designed running socks, and ensure your running shoes fit correctly. It’s also worth choosing running shoes with breathable mesh uppers, which can reduce the tendency for feet to get hot and sweaty.

Read our article about running blisters and how to prevent them.

7. Your legs could twitch as you lie in bed on a running day

Restless leg syndrome causes you to have an overwhelming urge to move your legs and can be especially noticeable at night after running. Running doesn’t actually cause restless leg syndrome but can make it worse if you’re prone to it. To tackle this issue, try stretching more after runs, and also reduce your caffeine intake.Check out ASICS runners’ stretching guide.

8. you could get a stitch from running

A stitch is a painful sensation that some people get in their stomach area when they exercise. It normally stops immediately if you stop running. To avoid running stitches, drink less water a couple of hours before your run, warm up correctly, and don’t eat much food before running.

9. Your nose might run more from running

Many runners notice they get a runny nose from their sport. It’s not exactly known why this happens, but Runner’s World magazine reports it could be due to with air pollution that runners are exposed to when pounding the streets.

10. You might need to go to the bathroom suddenly while running 

When you’re running, your bowels jiggle around. This can sometimes cause what is known as “runner’s trots” – a sudden need to relieve yourself. It can be uncomfortable and embarrassing. To avoid this, make sure you leave at least three hours to digest your food before going for a run, avoid overly spicy or fibrous foods, and avoid caffeine.

11. Your thighs may start itching a few minutes into a run

Some people get “runner’s itch”, which makes the skin in certain parts of your body (thighs are a common hotspot) feel itchy. When you run, your veins expand, which causes this strange sensation.

12. Your knees might crackle as you walk down the stairs

Sometimes, running can make our bodies behave in strange ways. One common side effect is that you could hear crackling or popping noises when walking down the stairs, squatting, or standing up from a chair. Although this can be disconcerting, it’s rarely a cause for concern, according to experts. However, if you also notice pain, then you should see a doctor.

13. You might get headaches during, or after, your run

Some runners get headaches during or after the exercise. There are various theories about why this might be, including dehydration, or the dilation of blood vessels inside your skull.

Beyond just the physical effects of running

Running is a brilliant way to exercise. It’s low cost, convenient, you can do it almost anywhere, and everyone - from running veterans to those just taking their first steps - can start reaping the rewards almost immediately.

To start building up your runner’s body - and to see how running changes it - pull on a pair of men’s running shoes or women’s running shoes, and take your first steps today!