5. Runners who average more than 80 km (50 miles) per week are twice as likely to suffer from respiratory illnesses. Those who run 20-30 km (12.4-18.6 miles) a week have a stronger immune system and are less prone to colds.
6. Regular running training is good for improving the long-term stability of bones. Researchers at the University of Michigan came to the conclusion that 12-20 minutes of running three times a week can increase bone mineral density.
7. The French ultramarathon runner Serge Girard holds the world record for the longest distance run in 365 days. He ran every day for a year, crossed a total of 25 countries and covered a total distance of 27,011 kilometers (16,783 miles).
8. Researchers have found that the majority of runners will straighten up when an attractive runner of the opposite sex is coming towards them.