Physical exercise has many benefits, but it might also have a negative impact on the body, depending on the training level, length of workout, gender, age and fitness. The negative effects of physical exercise are commonly attributed to an imbalance between the levels of antioxidants (both low molecular weight antioxidants and antioxidant enzymes) and reactive oxygen and nitrogen species due to excessive production of free radicals during physical exercise. In this critical review, we look for answers for three specific questions regarding the interrelationship between physical exercise and oxidative stress (OS), namely, (i) the dependence of the steady-state level of OS on fitness, (ii) the effect of intensive exercise on the OS and (iii) the dependence of the effect of the intense exercise on the individual fitness. All these questions have been raised, investigated and answered, but the answers given on the basis of different studies are different. In the present review, we try to explain the reason(s) for the inconsistencies between the conclusions of different investigations, commonly based on the concentrations of specific biomarkers in body fluids. We think that most of the inconsistencies can be attributed to the difference between the criteria of the ill-defined term denoted OS, the methods used to test them and in some cases, between the qualities of the applied assays. On the basis of our interpretation of the differences between different criteria of OS, we consider possible answers to three well-defined questions. Possible partial answers are given, all of which lend strong support to the conclusion that the network responsible for homeostasis of the redox status is very effective. However, much more data are required to address the association between exercise and OS and its dependence on various relevant factors.

The aim of the present study was to evaluate the apparent disagreement regarding the effect of a typical cycling progressive exercise, commonly used to assess VO2max, on the kinetics of ex vivo copper induced peroxidation of serum lipids. Thirty-two (32) healthy young men, aged 24–30 years, who do not smoke and do not take any food supplements, participated in the study. Blood was withdrawn from each participant at three time points (before the exercise and 5 minutes and one hour after exercise). Copper induced peroxidation of sera made of the blood samples was monitored by spectrophotometry. For comparison, we also assayed TBARS concentration and the activity of oxidation-related enzymes. The physical exercise resulted in a slight and reversible increase of TBARS and slight changes in the activities of the studied antioxidant enzymes and the lag preceding peroxidation did not change substantially. Most altered parameters returned to baseline level one hour after exercise. Notably, the exercise-induced changes in OS did not correlate with the physical fitness of the subjects, as evaluated in this study (VO2max = 30–60 mL/min/kg). We conclude that in healthy young fit men a short exhaustive exercise alters only slightly the OS, independent of the actual physical fitness.

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Aim To describe the results of a feasibility phase and the expected results of a new approach to increase the participation rate in a Colorectal Cancer Organized Screening Program (CRCSP) through Facebook awareness messages. Method This approach targets people aged 50-74 years, who reside in an urban deprived area and regularly connect to Facebook. The feasibility phase ran over 2 months (December 2018 and January 2019) in six municipalities (Seine-Saint-Denis, France). The full provisional campaign will run over a year. The approach consists of sending electronic awareness messages on the importance of screening for colorectal cancer using a specific Facebook module. Subjects who consent to screening complete a test-kit application form. The eligibility of each subject to participate in screening is determined by a doctor before the kit is sent out. Results A total of 39 900 people were reached by the feasibility phase campaign, and 9200 were able to watch at least one Facebook message/video. Of those, 4450 people logged to learn more about the CRCSP, 298 applied for a test kit, 160 test kit applicants were eligible to participate and the test completion rate was 41.9%. According to these feasibility results, 366 120 targeted people would connect regularly in the tested area, 141 541 of whom would be interested in a specific promotional message posted on Facebook. Requests could be made for 9770 kits, with 5246 people being eligible to participate in screening. The expected test-completion rate is estimated at 42%-89%. This would represent 5%-11% of the tests carried out in the area during the same period by 'classical' CRCSP. Conclusion Implementation of the Facebook strategy would significantly improve the rate of participation in the CRCSP by mobilizing people with no previous participation, including younger subjects.