BackgroundAthletes have a large extent of oxidant agent production. In the current study, we aimed to determine the influence of thyme extract on the endurance exercise performance, mitochondrial biogenesis, and antioxidant status in rats.MethodsTwenty male Wistar rats were randomly divided into two groups receiving either normal drinking water (non-supplemented group, n = 10) or thyme extract, 400 mg/kg, (supplemented group, n = 10). Rats in both groups were subjected to endurance treadmill training (27 m/min, 10% grade, 60 min, and 5 days/week for 8 weeks). Finally, to determine the endurance capacity, time to exhaustion treadmill running at 36 m/min speed was assessed. At the end of the endurance capacity test, serum and soleus muscle samples were collected and their superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, as well as malondialdehyde (MDA) concentration were measured. Protein expression of PGC-1α, as a marker of mitochondrial biogenesis, was also determined in the soleus muscle tissue by immunoblotting assay.ResultsFindings revealed that the exhaustive running time in the treatment group was significantly (p < 0.05) prolonged. Both serum and soleus muscle MDA levels, as an index of lipid peroxidation, had a threefold increase in the thyme extract supplemented group (t18 = 8.11, p < 0.01; t18 = 4.98, p < 0.01 respectively). The activities of SOD and GPx of the soleus muscle were significantly (p < 0.05) higher in the non-supplemented group, while there was no significant difference in serum SOD, GPx activities, and total antioxidant capacity between groups. Furthermore, thyme supplementation significantly (p < 0.05) decreased PGC-1α expression.ConclusionsThyme extract supplementation increased endurance exercise tolerance in intact animals, although decrease of oxidative stress and regulation of the PGC-1α protein expression are not considered as underlying molecular mechanisms.

Although high-intensity interval training (HIIT) is an efficient method to improve vascular function, maximal oxygen consumption, and muscle mitochondrial capacity, acute HIIT overstresses the oxidative and immune systems and causes muscle soreness and damage. The aim of the present study was to investigate the effects of date seeds on exercise-induced oxidative stress and aerobic and anaerobic performance following HIIT sessions. Thirty-six physically active men and women aged 18-35 years were assigned to take 26g/d of date seed powder (DSP, n=18) or wheat bran powder (placebo, n=18) before and after HIIT workouts for 14 days. Total antioxidant capacity (TAC), oxidative stress index (OSI), total oxidant status (TOS), superoxide dismutase (SOD), glutathione peroxidase (GPx), uric acid, malondialdehyde (MDA), and 8-iso-prostaglandin F2α (8-iso-PGF2) were determined at baseline, at the end of the intervention, and 24 hours’ post-intervention. We used the Cooper and running-based anaerobic sprint test (RAST) to assess aerobic and anaerobic performance at the study’s beginning and end. Independent Student’s t tests, analysis of covariance, and repeated-measures analysis of variance (ANOVA) were used to compare the quantitative variables. Positive changes were observed in TAC, TOS, OSI, GPx, MDA, and VAS after intervention and at 24 h post-exercise (p<0.05). Likewise, peak power and fatigue index were significantly improved in DSP in comparison to the placebo group. Levels of SOD, uric acid, 8-iso-PGF2, VO2 max, and average power were not changed after training. Our results showed that date seed supplementation in active participants performing HIIT bouts ameliorated oxidative stress and improved performance parameters.

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Background High intensity and endurance exercises lead to exercise-induced oxidative stress (EIOS), exercise-induced muscle damage (EIMD), and inflammation, which are the influencing factors on muscle soreness, localized swelling, and sports performance decrease. Therefore, the purpose of this study is to determine the effectiveness of Tribulus terrestris (TT) as an herbal supplement with antioxidant and anti-inflammatory properties on the nutritional, oxidative, inflammatory, and anti-inflammatory status, as well as the sports performance of recreational runners. Methods/design This study is a double-blind, randomized, placebo-controlled trial, which will be conducted among recreational runners of Tabriz stadiums, Iran. Thirty-four recreational runners will be selected, and participants will be assigned randomly to two groups: to receive 500 mg TT supplement or placebo capsules twice daily for 2 weeks. Both groups will do high-intensity interval training (HIIT) workouts during the study. Baseline and post-intervention body composition, muscle pain, and aerobic and anaerobic performance will be assessed. In addition, assessment of malondialdehyde (MDA), total antioxidant capacity (TAC), total oxidant status (TOS), superoxide dismutase (SOD), glutathione peroxidase (GPx), uric acid (UA), 8-iso-prostaglandin F2α (8-iso-PGF2α), protein carbonyl (PC), catalase (CAT), glutathione (GSH), nitric oxide (NO), high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α), creatine kinase (CK), myoglobin (MYO), lactate dehydrogenase (LDH), insulin-like growth factor-1 (IGF-1) irisin, cortisol, and brain-derived neurotrophic factor (BDNF) will be done during three blood samplings. Changes in oxidative stress, anti/inflammatory biomarkers, and sports performance will be assessed as primary outcomes. Discussion This study will be the first to assess the potential effects of TT on recreational runners. Our results will contribute to the growing body of knowledge regarding TT supplementation on the nutritional, oxidative, inflammatory, and anti-inflammatory status and sports performance in recreational runners. Trial registration Iranian Registry of Clinical Trials (www.irct.ir) (ID: IRCT20150205020965N8). Registration date: 13 February 2021.

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