The use of a hydrocarbon breath test has been underutilized in exercise research. The peroxidation of n-3 and n-6 fatty acid families results in the production of the volatile alkanes ethane and pentane. The compounding problems with this approach include the fact that the atmosphere breathed may be contaminated by hydrocarbons and our gastrointestinal tract bacteria also make these compounds. Snider et al.⁹ have found that the contamination problems can be overcome by including a wash out period, during which the subjects breathed hydrocarbon-free air prior to the experimental period.

During radical reactions, there is an electron jump from ground state to an excited state. When the electron falls back to ground state, a low level of light energy is emitted; this is called chemiluminescence. We employ a single photon counting system similar to that described by Boveris et al.¹⁰ to determine a tissue s ability to defend itself against oxidative stress. The tissue can be challenged by various organic or inorganic hydroperoxides. When a variety of antioxidants are systematically added to the incubation mixture, the procedure may yield evidence to implicate the radical species that may be involved.

Recently we have begun to couple assays of mitochondrial oxygen consumption and the chemiluminescence analysis, with the intent of developing a model system for the study of oxidative stress. Robinson and co-workers¹¹ have demonstrated that an increased electron flux capacity is necessary to achieve the increased peak oxygen consumption derived by training. Furthermore, Kehrer and Lund¹² have provided an excellent review on the relationship between cellular reducing equivalents and oxidative stress. We employ myxothiazol, a tight inhibitor of complex III, in mitochondrial suspensions. This results in an inhibition of state III respiration and a subsequent increase in chemiluminescence. Although still in the preliminary stages of development, this approach offers some promise, since reducing equivalents and antioxidants can easily be added to the system.

Obviously, in viva studies involving antioxidant supplementation should be accompanied by marker assays to demonstrate that the dosage regimen has altered the antioxidant concentration. The Methods in Enzymology series^13-16 end Evans et al.¹⁷ text provide a convenient source of reliable assays. Since antioxidants often are involved in an interrelated chemistry, it is useful to attempt to understand how the protocol of interest has influenced the total milieu. Cao and co-workers have developed a technique suitable for that purpose.¹⁸

Needed Research
To date, the preponderance of studies related to exercise and oxidative stress have centered on determining evidence of stress and the influence of one antioxidant at a time. Literature related to a multiple supplement approach is sparse. While youth sport leagues in the United States expose children to high aerobic doses, there are virtually no oxidative stress-related data available on children younger than age 18. Furthermore, just as some members of the general population are apt to receive orthopedic trauma from certain types of intense aerobic activity, we might assume that some genetic sets are unable to cope with oxidative stress. Oxidative stress research is needed to detect aberrant responses to exercise rather than to focus on group means. Finally, we are beginning to understand that radicals play many vital roles in our biochemistry. We must question whether massive doses of antioxidants are violating that beneficial chemistry.