Free radical chemistry. Relationship to exercise.

Free radicals are molecules or molecular fragments containing an unpaired electron in the valence shell. Radicals interested only a few chemists until 18 years ago when an enzyme was discovered which functioned to remove a specific oxygen-centered radical. That discovery renewed interest in radicals and has already begun to alter thinking on many clinical problems. Free radicals have been shown to be common phenomena that play a role in normal biochemistry but require an elaborate control system to be held in check. Since oxygen-centered radicals are produced in intermediate metabolism, exercise should increase their production and that has been shown to be so. There is also evidence that the consumption of large quantities of ambient oxygen during exercise induces harmful chemistry known as lipid peroxidation. Presently, there are insufficient data available to ascertain how the human body tolerates such increased production of free radicals and lipid peroxidation and how the consequences of that chemistry might relate to the overall well being of exercising humans.