Day 1: Your body will release endorphins

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It's a well known fact that when you start running, your body will begin to produce endorphins, which not only improve our overall mood, but make us feel great during and after the run. Sometimes, it can be as simple as remembering mind over matter. This is the start of your journey, hang on in there!
Day 2: Calories will burn even after your run

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Calories are burned when our body enters that fat burn mode, so not only are your calories flying away during the exercise, the heightened heart-rate after the run will also be encouraging your body to drop those extra kcals. If this isn't enough of a reason, I don't know what is!
Day 3: You might notice that you're chafing

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I think we can all agree that chafing is like hell! It arises when the skin on one region of your body rubs against more skin or your clothes. It can appear in all sorts of places: the thighs, the underarms, the nipples, and the area around the bra straps. Try switching your gear to high-quality, breathable running clothes.
Day 4: You'll experience what they call the "runner's high"

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I know what you're thinking, what is this "runner's high" everyone is banging on about. Well, a mile run can make you happy and calmer and actually increase your anandamide, which causes marijuana-like effects, so obviously it makes us feel fantastic after a run.
Day 5: It'll get easier to do your run!

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By day five you might have noticed that the time in which you do your run is actually decreasing, or that you're becoming less out of breath on your way round your track. That's because you're conditioning your body to become used to the extra exercise, stick with it and you'll be a pro in no time!
Day 7: It's possible that your knees will start to hurt

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Okay, so it's thought to be a myth that running can be detrimental to your knees, but by this point they might be feeling a little achey. You can prevent knee pain by strengthening your legs, using the right shoes, and possibly even using straps or knee-pads to stabilize your knees.
Day 9: You'll feel less tired on your run

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Ever wonder why a good run energizes you? Well, running pumps blood and oxygen to all our muscles while also improving our cardiovascular stamina and minimizing lung demand, helping our body use energy more efficiently. Not to forget that it actually improves your sleeping schedule!
Day 10: Blisters will make an appearance!

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Day 10 might see you coming to terms with some painful blisters on your feet. They form when the skin of the foot scrapes against the inside of a shoe or sock, which is especially prone to happen when the foot is warm or wet. Tip: running shoes with mesh uppers are great since they allow air to circulate and cool down your feet.
Day 12: You'll begin to feel less stressed than you were before

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Now I know that the last thing we want to do when stressed is go on a run, so see it as a preventative. Stress causes all sorts of issues including headaches and weariness. Running lowers stress hormones and boosts endorphin production for relaxation and positivity.
Day 13: Spots might start to appear on your face

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The increased amount of sweat being produced in our face and forehead can lead to our pores being blocked. You know what that means don't you? Spots! By day 13 you might have noticed that your face has come up in blemishes, but don't worry, stick to a gentle, helpful skin routine and you should be fine.
Day 14: Headaches are not uncommon at this stage!

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This is a bit of a weird one and we hope that you're not experiencing it, but for some runners, the act of running itself or the time spent exercising afterwards causes a headache. Several potential causes have been considered, such as dehydration or the expansion of blood vessels within the skull.
Day 15: Your overall mood will have improved

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Studies show that aerobic activity can surprisingly alleviate mental illnesses that affect our mood, like depression. New neural networks dampen the depressive symptoms. Running a mile daily may improve your mood if you have depression, anxiety, or other mental health difficulties.
Day 16: Your legs will start to twitch

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Just over two weeks of your one-mile-a-day regime might see an intense compulsion to your legs or an uncontrollable twitching. A helpful tip to reduce these symptoms is reducing the amount of caffeine in your diet, and also focusing on your post-run stretches!
Day 17: You'll start to become less anxious than you were before

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There have been studies that show that running regularly (one mile a day) can actually decrease our levels of anxiety. So by this point in your one mile a day challenge, you might feel that the worries and anxieties you had before are slowly being dampened by your physical activity.
Day 20: Running will help maintain your blood pressure

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High or low blood pressure can take its toll on our bodies if we don't monitor it properly. The blood arteries widen and the blood flow increases when we run, lowering your resting blood pressure. At the same time as it lowers bad cholesterol, running can raise the good kind of cholesterol by stimulating enzymes.
Day 21: You'll start to shed that weight!

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Even if you don't maintain a proper diet, running one mile a day can easily burn off as much as one pound every month. Increased physical activity and reduced calories help us to lose weight, which we all know, and due to the extra calories burned, running a mile a day will most probably help.
Day 22: You'll notice your muscles have strengthened

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Running engages the lower body, back, and core, so many muscles actually benefit from your mile jog. While running, your body utilizes your gluteals, hamstrings, foot and hip flexors, and quadriceps, and your core and back muscles support lower your body muscle power by maintaining balance and posture.
Day 25: You might notice that your muscle mass will decrease

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Depending on your eventual goal, this could either be a bonus or a con. When we run, our bodies' natural response is to try to shed any extra weight, including muscle, that could slow us down. Makes sense, huh? Well, to prevent that muscle loss you can consider consuming enough protein before, during, and after exercise.
Day 26: Your nose starts to run more...

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Believe it or not, a common side effect of running is a runny nose (pun not intended), and you might be noticing that by this point. Although the specific cause is unknown, Runner's World suggests that runners' exposure to air pollution while racing through city streets may be to blame.
Day 27: Your metabolism will begin to speed up

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By around this time, you might have noticed a slight change iin your metabolism. This is because our metabolism determines whether we burn or store calories and faster metabolisms burn more calories each hour. Your metabolism will continue to speed up longer after a more strenuous run. Go hit that pavement!
Day 28: Your confidence will sky-rocket

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Listen, by this point in your running journey, your body is probably beginning to look a little bit different. Having said this, you will notice a change and hopefully feel better about yourself and within yourself, boosting your self-esteem and confidence too.
Day 30: Your learning and memory will improve dramatically

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While you might not have even considered it, moderately intense jogging strengthens our memory and thinking centers of the brain. It's been proven that jogging betters our vocabulary learning, according to a Neurobiology of Learning and Memory study, and running before studying a new idea may help you grasp it.
Day 32: Your lungs will get noticeably stronger

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Running has all sorts of benefits on our body, and one of them is training our lungs to take in as much oxygen as possible and to be more efficient. By day 32 of running a mile a day, you might have noticed that your breathing has somewhat changed, and you can catch your breath better.
Day 35: Your bones will become stronger

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As you get older, your bone density reduces and can cause osteoporosis. Although it's been told that strength training strengthens bones (which is true), running is as equally helpful to strengthen your bone density and can reduce your risk of injury.
Day 40: Your chest could start to sag

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Ladies, listen up, make sure you get a semi-decent support bra when going on your run! The wrong sort of bra when jogging can actually cause breast sagging in women. Wearing a sports bra while running is recommended for women of all sizes since it provides the necessary support for the bust, improves comfort, and lessens the likelihood of drooping.
Day 42: You'll start to get that runners body

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Who doesn't want that runner's body, eh? By day 42 you will have probably already started to notice a difference in your bod. Yeah, while it might not be as dramatic as this guy's progress, your body will have probably become more toned and look fitter than ever.
Day 48: You might get "runner's face"

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Running daily may also cause something known as "runner's face." Basically, your skin may age and sag. Experts believe that jogging and other physical activities can cause more damage to your skin than it means to, specifically to your collagen and elastin, which are essential for a youthful glow.
Day 49: Your toenails could actually go black from running everyday

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Runner's toenail, in which the big toe nail turns black, is a common side effect of ramping up one's running routine. So on this day of your one mile a day routine, you might find yourself with black toenails! Too-tight socks or shoes can be leading causes of runner's toenail and you may want to consider replacing them.
Day 50: Your heart will be stronger than it ever was before

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We all know that it's super important to look after our heart, right? Well, running regularly actually strengthens your heart by making it work harder, lowering your resting heart rate and increasing oxygen intake. Running a mile a day reduces heart attack and stroke risk by 45%.
Indefinitely: Running reduces your risk of cancer

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Last, but certainly not least, is the reduced risk of cancer when you run a mile a day. Many theories have been presented regarding how exercise lowers cancer risk, including its potential to reduce inflammation and increase immune system function, prevent obesity and high insulin levels, and lower cancer-causing hormones and growth factors. So what are you waiting for? Get out there now!
And Now... The Pros And Cons Of Running! Pro: Overall Fitness Improvement

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There's no denying that running is the ideal exercise to try each and every day if you want to improve your fitness performance. It's ideal for improving your heart and lung health, as well as improving your bone health - which is always a good thing when you're getting older!
Con: Does Running Cause Osteoporosis In The Knee?

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There have been many indications that running can actually increase the risk of developing osteoporosis (where the bones weaken) in the knees because of the impact on bones with regular running. However, there has been a lot of research to suggest that this isn't the case.
Pro: It's A Great Social Activity!

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If you're looking for an exercise that will help you to meet fellow runners and make new friends, the good news is this sport is perfect for doing with other people. You can join a running group, meet other runners on the road or even take part in marathons and sponsored runs.
Con: A Lot Of Running-Related Injuries

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There are some injuries that can be exclusive to runners due to this particular exercise, and it might be that you suffer through a lot of them if you're running regularly. These can include: shin splints, runner's knee, stress fractures, Achilles tendonitis and plantar fasciitis (pain at the bottom of the foot).
Pro: It's One Of The Better Exercises For Weight Loss

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The good news is that if you're looking for the best sport to help you lose weight, running is one of the best exercises for this. Because it's such a high-intensity exercise that uses a lot of muscles, you'll be pretty much guaranteed to lose weight if your diet plan is matching up.
Con: But You Could Actually Gain Weight!

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So... you might be confused - but stick with us! Yes, running can help you to lose weight if you're not eating too many calories alongside your exercise plan. But the reason that running could go the opposite way is because it can make you gain weight in terms of the muscle mass you're accumulating - which isn't necessarily a bad thing!
Pro: You'll Feel A Huge Sense Of Accomplishment

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Because running is an exercise you can easily keep track of in terms of mileage, routes and different terrain - as well as setting yourself goals and seeing actual results - it's very easy to feel a huge sense of accomplishment when you see how far you've come, which means a great self-esteem boost!
Con: You Might Feel More Pressure From Other Runners

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Because running is such a social and team sport - as well as many 'official' challenges being put out there - it's also very easy to suffer from peer pressure. You might feel like a failure if you don't do what all the others are doing, and it's easy to push yourself too far with running and burn yourself out.
Pro: It's On The Cheap Side

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In terms of the investment and expense needed, running is actually a very cheap exercise. All you need is a good pair of running shoes, and you can run anywhere you like without having to pay expensive membership charges or pay to get into places like the gym in order to work out!
Con: But It Can Easily Get Expensive

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Although running can always be a very thrifty sport, it's very easy to get sucked in to spending
a lot of money. This all depends on how much self control you have, but running could see you splashing out on the latest and greatest fitness tracker watches, running outfits, shoes and more.
Pro: It's One Of The Best For Motivational Playlists!

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There's no doubt that an epic motivational playlist can truly transform a workout - the right music just makes your workout hit that much harder. And running is one of the best exercises you can do if you love listening to music while exercising, because it's ideal for sticking your headphones in!
Con: It Can Be Addictive

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Any exercise can be addicting, of course, but running can be one of the most addictive. This is because of the huge burst of endorphins it gives you as a high intensity exercise, but it's also because running is one of those you can decide to do every single day to lose weight and keep fit and then get addicted to it so that you can't compromise on skipping a day.
Pro: It Improves Your Circulation

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Running is a great exercise for circulation all round - not only in the legs you're using to propel yourself forward, of course, but also because it's a high-intensity exercise that will get your heart pumping blood around your body that little bit faster - which is always a good thing!
Con: It's Easy To Do Too Much Too Soon

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When you're a beginner to running, it's very easy to try and do too much too soon - because running is really hard to gauge what's too far, or what's too much of a challenging route. You might end up straining or injuring yourself because you were trying to do too much at a beginner level.
Pro: It Could Help With Depression And Anxiety

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Running has proven to be a fantastic exercise for both the mind and body, as it reduces stress and provides an exercise that releases a ton of endorphins. This is great news for your mind specifically, and it can actually help combat symptoms of depression and anxiety in some people.
Con: If You Run Solo, You Could Develop Bad Technique

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Running is often a sport people do on their own, if they prefer to exercise alone or avoid any huge running groups. The trouble with this is, if you start out alone it's very easy to develop bad form when running (such as landing the wrong way) with nobody to see it or call you out on it.
Pro: It's An Exercise You Can Do Anytime Of The Day

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For people with crazy busy schedules, there are certain exercises that need to be done a certain time of day - like strict workout class schedules, or the based around the pool opening times - but with running, there is complete freedom about when you want to do it: morning, lunch or night.
Con: It Often Requires Other Types Of Exercise To Make The Most Out Of It

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To progress with running, and to give yourself the best possible chance of avoiding injury, you'll definitely need to do other exercises alongside it, which can feel like a chore for a lot of people. Exercises like hip strengthening, focus on leg muscles and building core strength will all help you with running - but it can seem like extra effort.
Pro: You'll Usually Have Better Sleep!

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The most high intensity exercises are the ones that will leave you feeling worked out - and very sleepy - which is why running is a great one to give you a better night's sleep. Especially if you go running in the evening, it can mean you're more tired before bed.
Con: You Often Have To Contend With Risky Environments

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Running will see you outside facing many different types of risks, compared to working out at home or in the gym. This could be running on a busy traffic route if that's where you live, running with music in so you can't hear what's going on around you, or contending with difficult terrain if you're running on trails that might result in an injury.