Redox Homeostasis and Inflammation Responses to Training in Adolescent Athletes: a Systematic Review and Meta-analysis

Abstract

Background: Several studies have highlighted the substantial role of the athlete's redox and inflammation status during the training process. However, many factors such as differences in testing protocols, assays, sample sizes, and fitness levels of the population are affecting findings and the understanding regarding how exercise affects related biomarkers in adolescent athletes. Objectives: To search redox homeostasis variables' and inflammatory mediators' responses in juvenile athletes following short-or long-term training periods and examine the effect size of those variations to training paradigms. Methods: A PRISMA-compliant systematic review and meta-analysis were conducted. The entire content of PubMed (MEDLINE), Scopus, and Science Direct were systematically searched until December 2019. Studies with outcomes including (1) a group of adolescent athletes from any individual or team sport, (2) the assessment of redox and/or inflammatory markers after a short-(training session or performance testing) or longer training period, and (3) variables measured in blood were retained. The literature search initially identified 346 potentially relevant records, of which 36 studies met the inclusion criteria for the qualitative synthesis. From those articles, 27 were included in the quantitative analysis (meta-analysis) as their results could be converted into common units. Results: Following a short training session or performance test, an extremely large increase in protein carbonyls (PC) (ES 4.164; 95% CI 1.716 to 6.613; Z = 3.333, p = 0.001), a large increase in thiobarbituric acid reactive substances (TBARS) (ES 1.317; 95% CI 0.522 to 2.112; Z = 3.247, p = 0.001), a large decrease in glutathione (GSH) (ES − 1.701; 95% CI − 2.698 to − 0.705; Z = − 3.347, p = 0.001), and a moderate increase of total antioxidant capacity (TAC) level (ES 1.057; 95% CI − 0.044 to 2.158; Z = 1.882, p = 0.060) were observed. Following more extended training periods, GSH showed moderate increases (ES 1.131; 95% CI 0.350 to 1.913; Z = 2.839, p = 0.005) while TBARS displayed a small decrease (ES 0.568; 95% CI − 0.062 to 1.197; Z = 1.768, p = 0.077). Regarding cytokines, a very large and large increase were observed in IL-6 (ES 2.291; 95% CI 1.082 to 3.501; Z = 3.713, p = 0.000) and IL-1 receptor antagonist (ra) (ES 1.599; 95% CI 0.347 to 2.851; Z = 2.503, p = 0.012), respectively, following short-duration training modalities in juvenile athletes.

Blood Profile of Cytokines, Chemokines, Growth Factors, and Redox Biomarkers in Response to Different Protocols of Treadmill Running in Rats

“…A considerable increment of lipid peroxidation products (LOOH, MDA) content noticed in running groups resembles observations in rats subjected to strenuous exercise (i.e., speed of running: 30 m/min, time:~60 min, 70-75% VO 2 max) [38] and well-trained humans who underwent acute exercise [8]. It is not surprising, as the increase in both saturated and unsaturated fatty acids was noticed in training animals, as we previously reported [23].…”

“…Especially, high energy demands and oxygen consumption are connected with increased number of electrons supplied to the respiratory chain and reactive oxygen (ROS) and nitrogen (RNS) species' generation [7]. Muscle injury is also linked with specific leukocyte subsets' infiltration [8] and interactions between released metmyoglobin/methemoglobin with peroxides [9], culminating in the release of inflammatory mediators and ROS/RNS. Free radicals could also serve as signaling molecules accelerating inflammation [10,11].…”

The Interplay between Oxidative Stress, Exercise, and Pain in Health and Disease: Potential Role of Autonomic Regulation and Epigenetic Mechanisms

“…Many studies explored the effect that prolonged training might exert on oxidative stress in healthy people. Several studies reported that training alleviates exercise-induced oxidative stress by modulating the antioxidant capacity in humans (for a review, see [ 63 ]). However, not all training modalities and intensities have the same beneficial effect.…”

Acute moderate-intensity exercise increases total antioxidant capacity and anti-inflammatory responses in competitive cyclists: The role of adiponectin

“…9 In addition, acute training may induce oxidative stress, but most studies have shown an increase in total antioxidant capacity (TAC) during medium or high intensity training. 10,11 Little information is available on how low intensity anaerobic or aerobic exercise (⩽50% VO 2max ) affects antioxidant levels. While many studies focused on skeletal muscles, only a few have investigated adipose tissue (AT) secretion following a vigorous workout in nonobese individuals.…”

“…27 Acute training also induces antioxidant protection by increasing TAC, which was demonstrated in the studies at the end of short-acute exercise training in athletes. 10 Although, intensive physical training can generate excessive reactive oxygen species, interestingly, regular training leads to an increase in TAC and antioxidant enzyme and their activity in skeletal muscles. 28,29 Changes in enzyme activity and TAC under physical exhaustions in regularly trained versus untrained subjects are ambiguous.…”