For someone hoping to become a better, faster runner and potentially get engaged in high intensity activities (e.g. marathon) no additional health benefits should be anticipated, but rather a slightly increased risk for heart problems, as well as for running-related injuries and disabilities.
This should not be a reason to discourage high intensity activities, for those who really enjoy it either for leisure or as an anti-stress activity. The overall benefits of running far outweigh the risks for most individuals.
Many would otherwise endorse the following moto: "I don't run to add days to my life I run to add life to my Days".
These are some recommendations endorsed by the International Marathon Medical Director's Association to reduce health risks for high intensity runners:
1. Participants should not only be sufficiently trained, but equally important, they should have a goal and corresponding race plan that is appropriate for that level of training and fitness. If not, do not attempt the distance.
2. Have a yearly physical examination and be sure to discuss your exercise plans, goals and intensity at that visit.
3. Take one baby aspirin (81mg) on the morning of a long race if there is no medical contraindication and you are >40 years old.
4. Consume less than 200mg caffeine before and during a 10K race or more.
5. Only drink a sports drink or its equivalent during a workout of 10k or more.
6. Drink for thirst. Do not drink to the max.
7. Do not consume a NSAID just before or during a race. You can use it at the end of the race as needed.
8. Consume salt (if no medical contraindication) during a 10k or more.
9. During the last mile, maintain your pace or slow down; do not sprint the last part of the race unless you have practiced this in your training. Run as you train.