People who want to start running are looking for reasons that running good for your health and runners want confirmation that running, amid some of the bad press that always surrounds different sports, really isn't as bad as the press sometimes makes it out to be.

The truth is really that running is good and bad for your health. Knowing both the good and the bad can help you to prevent the bad things and revel in the good things. Here is the truth about whether running is good for your health.

Let's start with the things about running that are good, and even great, for your health. First and foremost, running reduces your risk of cardiovascular disease which is the number one killer of women. In the Nurses Health Study conducted as a collaboration between Harvard Medical School and Brigham and Women's Hospital researchers found that women who most active had a heart attack rate that was 44% less than those women who were sedentary. (1)

Running has other positive effects on risk of cardiovascular disease such as strengthening the heart muscle, reducing the risk of clot formation, prevents hardening of the arteries, lowers triglycerides and cholesterol and raises HDL cholesterol.

Research published by Dr. Williams from Lawrence Berkeley Laboratory in California found that runners who enjoyed high mileage weeks had the best effect on raising HDL while those who concentrated on speed work had a better effect on lowering triglycerides. (2)

Running also reduces your heart rate and blood pressure. These are secondary affects of the heart muscle being stronger and less hardening of the arteries which contributes to high blood pressure.

Most good cardiovascular exercise, including running, reduces the risk of stroke which is the second leading killer of women. These again are secondary effects of lower blood pressure and a strong cardiovascular system. Studies have also proven that physical activity will lower the risk of breast cancer. In a study published in the New England Journal of Medicine found that those who were most active had a 37% lower risk of breast cancer compared to the group of women who are sedentary.

Physical exercise also enhances the immune system. Researchers have found higher levels of lymphocytes (the cells that attack disease) in the blood during and after exercise. It seems these cells are recruited during physical activity to protect the body. This can also have a negative effect when the runner puts in high mileage, such as a marathon. This can leave the athlete open for viral infections when the lymphocytes are depleted after these activities.

Physical activity, including running helps diabetics to more completely control their blood sugar, it keeps the intestinal tract running regularly and enhances and strengthens your respiratory system. Running also helps to ease menstrual and post menopausal symptoms, it helps to prevent bone loss associated with age, it helps to prevent a decline in reaction time and leads to a long and happy life.

Although there are many reasons that running good for your health there are several things that may have a negative impact on your health as well. Running isn't the filthy habit that it's been made out to be with bad knees, torn cartilage and ripped tendons. If you run strictly for fitness, about 30 minutes several times each week, then you don't have much to worry about.

On the other hand, when you push your body beyond these limits you are heading for performance and performance means more than fitness, it pushes you body to the limit. This pushing can result in damaged cartilage, torn tendons and potentially increases your risk of arthritis.

Knowing these risks can help you to prevent the damage by protecting your joints through stretches and strengthening the muscles that support the ankle, knee and hip joints. You should also listen to your body and when it's has had enough don't push. It can be fun to run a couple of 10K races but unless your dreams, and talents, have you heading for the Olympics, fitness may be your best option.