If so, are there any negative side effects from running too much?

 

Does running increase one's oxygen uptake?

 

Additionally, would free radical intake increase and thereby be harmful to your body?

Over training will lead to sports injuries - most runners will have experienced plantar fasciitis, shin splints, knee sprains etc. to varying degrees. As you build up muscle power and endurance it becomes less frequent. Degenerative osteoarthritis over time.

 

Other problems like exercise induced asthma too.

 

I don't think you need to worry about free radical damage from running. Molecular oxygen is stable, your arterial oxygen tension may increase with increased ventilation but your bodily cellular mitochondrial function is intact, and cells have a physiological reserve of antioxidants like glutathione to mop up excess radicals. It's not like the case in ischaemic reperfusion injuries where damaged cells are exposed to oxygen.

If so, are there any negative side effects from running too much?

 

Does running increase one's oxygen uptake?

 

Additionally, would free radical intake increase and thereby be harmful to your body?

 

 

You will destroy your knees unless you run on grass. The human body is not built to run on pavement.