Some of the Benefits of Running

I run almost everyday and every so often someone tells me: “Running is no good for you, it’s too hard on your joints, knees and your body. You should not run that much!" 
While everyone is entitled to their own opinion, I’ll stick to my guns and say: “Everything has pros and cons, but if done right, running it’s actually good for you, very good for you!”

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Protects your heart

Running just 10 miles a week reduces the risk of heart disease by an impressive 42%, according to a study published in the British Medical Journal1. Any form of aerobic exercise is good for the heart, although a study conducted at Harvard Medical School found that more vigorous activities, like running, are more effective in increasing health.

Adds years to your life

A research published in the Journal of Science and Medicine in Sport found that runners live between 2.8 and 5.7 years longer than the general population2.
As well as adding years to your life, running will add life to your years. Increasingly, scientists believe that changes in fitness levels as we age are not down to chronology but as a result of becoming less active as we get older, lowering energy expenditure and causing muscle mass to decline.

Improves your mood

People that are more physically active report greater levels of excitement and enthusiasm than less active people. The “euphoria” sensation will occur also on days when they are more active than the usual.
You don’t have to be the fittest person on the block in order to get the benefits of exercising. Once you get your activity going the feel-good reward will kick-in eventually3.

Strengthens your bones

You’ve probably heard the term ‘use it or lose it’ in relation to muscle strength and tone – well, the same is true of bones. ‘Loading’ bones, through weight-bearing exercise, is what makes them adapt and grow stronger.
Furthermore, University of Missouri researchers have found that high-impact activities, such as running, might have a greater positive effect on BMD than resistance training4.

Makes you smarter

A study conducted at the Montreal Heart Institute shows that high-intensity training can make you fitter than ever: mentally fit!
The research shows that exercise increases production of key brain chemicals that encourage the growth of new cells and help develop new neural pathways (lines of communication between the brain and the body)5.

Maintains joint health

Perhaps because it seems intuitively true, the notion persists that running, especially when done long-term and over long distances, is bad for the joints.
But over the past few years, an emerging body of research has begun to show the opposite, especially when it comes to running. Not only is there no connection between running and arthritis, the new studies say, but running — and perhaps regular vigorous exercise generally — may even help protect people from joint problems later on6.
Movement is what gets synovial fluid - the sticky stuff that coats joint endings - flowing, keeping joints nourished and healthy. A Stanford University study put paid to the idea that running is bad for joints – the researchers monitored 500 runners and 500 non-runners over a 20-year period and found that it was the non-runners who suffered more wear and tear on their joints7.

Raises energy levels

When you’ve had a hard day, a run in the park may be better than a nap for boosting energy and fighting fatigue.
New research suggests regular exercise can increase energy levels even among people suffering from chronic medical conditions associated with fatigue.It may seem counterintuitive, but researchers say expending energy by engaging in regular exercise may pay off with increased energy in the long run8.

Keeps you in shape

Since running entails transferring your body weight from one foot to another approximately 10,000 times per hour, it’s a seriously energy-hungry activity. Running 3 miles, 3 times a week, will torch around 1000 calories. As well as helping to keep excess body fat at bay, running also tones and strengthens every muscle from the waist down.

Considerations

Generally, people who tell you running is no good for you aren't runners. Everything has pros and cons. You can sit on the couch and you won't injure your knee but you'll probably get fat and die of diabetes or heart disease. People who are runners (like me) will tell you of its wonderful benefits.
Personally I'd rather die a lion than live a mouse.

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References 
1 http://www.sign.ac.uk/pdf/sign97.pdf 
2 http://sma.org.au/wp-content/uploads/2010/07/Mortalityandlongevityofeliteathletesarticle.pdf 
3 http://www.theironyou.com/2012/02/exercising-improves-your-mood.html 
4 http://munews.missouri.edu/news-releases/2009/0226-hinton-bone-density.php 
5 http://www.newswise.com/articles/sport-makes-middle-aged-people-smarter 
6 http://www.time.com/time/health/article/0,8599,1948208,00.html 
7 http://med.stanford.edu/news_releases/2008/august/running.html

8 http://www.webmd.com/diet/news/20061103/exercise-fights-fatigue-boosts-energy