Analysis and monitoring of oxidative stress in exercise and training by FTIR spectrometry.

The increase in oxygen uptake during intense exercise is associated with an increase in the production of reactive oxygen species, a process known as oxidative stress, which may alter cell contents. To limit the damaging effect of this overload of free radicals, the antioxidant defense system must be effective. The repetition of endurance training stimuli causes adaptations of the antioxidant defense system, notably by enhancing the antioxidant capacity of various enzymes, metals, and vitamins. However, the monitoring of training-induced antioxidant system enhancement is not routinely available in most laboratories. Measurement of blood-derived markers of oxidative stress effects has been proposed to monitor adaptations to hard training. Fourier-transform infrared (FTIR) spectrometry offers several advantages by quantifying the level of shortto midterm oxidative stress of endurance training on erythrocytes. This review shows the relevance of using sophisticated biochemical information to assess the ability of athletes to tolerate high oxidative stress during hard training. High-intensity and/or long-term exercise increases oxygen consumption, causing changes in the intracellular equilibrium between the pro-oxidant and antioxidant systems. The mitochondrial electron transport chain (METC), xanthine oxidase (XO), and several organometallic compounds have been identified as major sources of intracellular free radical generation during exercise. An increased production of reactive oxygen species (ROS) under any abnormal physiological situation challenges the cellular antioxidant defense system to limit or avoid cell damage. Under oxidative stress, antioxidant vitamins and glutathione may be depleted, increasing tissue susceptibility to ROS. However, enzymatic and nonenzymatic parameters of the antioxidant system have been shown to adapt positively to chronic exercise (training). As an electron acceptor, oxygen allows mammalians to use, via metabolic pathways, the energy stored in macronutrients such as carbohydrates, fats, and proteins. This catabolic process generates oxygen free radicals and ROS derived from oxygen as a byproduct of its metabolism in cells. In chemistry, free radicals are atomic or molecular species with unpaired electrons on an otherwise open shell