Acute Hormonal and Inflammatory Responses following Lower and Upper Body Resistance Exercises Performed to Volitional Failure.

This study aimed to investigate the effects of a single bench press (BP) vs. leg press (LP) resistance training sessions on testosterone, cortisol, C-reactive protein (CRP) interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) concentrations, and creatine kinase (CK) activity in strength-trained males. Eleven strength-trained males participated in a cross-over randomized trial, undergoing two experimental sessions each consisting of five sets of the BP or the LP exercise to volitional failure with a load corresponding to 50% of one-repetition maximum. Blood samples were taken at baseline (BA), immediately post (POST), and 1 h after the cessation of exercise (POST-1). A significant increase in IL-6 concentration from BA to POST-1 was observed during the LP condition (p = 0.004; effect size [ES] = 0.64). Additionally, a significant main effect of time was found for increasing testosterone concentrations from BA to POST exercise (p = 0.014; ES = 0.25). A significantly lower cortisol concentration at POST-1 compared to POST (p = 0.001; ES = 1.02) was noted in the BP condition. Furthermore, a significantly lower cortisol concentration was found at POST-1 in the BP compared to the LP condition (p = 0.022; ES = 1.3). A significant increase in CK activity was reported from BA to POST (p = 0.024; ES = 0.69) and POST-1 (p = 0.045; ES = 0.55) during the LP condition, and from BA to POST-1 (p = 0.014; ES = 0.96) during the BP condition. No significant differences were found in the CRP (p = 0.659) and TNF-α concentrations (p = 0.487). These results suggest that the amount of muscle mass engaged during the resistance exercise may influence the changes in IL-6 and cortisol concentrations. Larger muscle groups, as engaged in the LP, more likely lead to elevated concentrations of IL-6 myokine.

The Influence of Whole-Body Cryotherapy or Winter Swimming on the Activity of Antioxidant Enzymes.

The aim of this study was to investigate the effect of a series of 20 whole-body cryotherapy sessions and 20 winter swimming sessions on the level of catalase, glutathione peroxidase and superoxide dismutase. The experimental group consisted of 60 people (30 people received cryotherapy and 30 people swam in cold water). The control group-without intervention: 30 people. Each of the three groups was tested twice. Analyzing the changes in the examined indicators, a statistical increase of CAT was observed in men after the use of WBC, as well as an increase of SOD in women and a decrease of SOD in men after the winter swimming season. Regular WS does not seem to place an excessive burden on the body in terms of intensifying oxidative processes. WS sessions once a week can be recommended as an effective method of improving health by causing positive adaptive changes and strengthening the body's antioxidant barrier. WBC may be used as an adjunct therapy in the treatment of diseases caused by oxidative stress, as it improves the body's antioxidant capacity. Further research is needed to elucidate antioxidant mechanisms in humans and to determine the short- and long-term effects of exposure to WS and WBC.

The effect of a series of whole­body cryotherapy treatments on the activity of antioxidant enzymes in healthy women and women with multiple sclerosis.

The study aimed to compare the effect of a series of 20 sessions of whole­body cryotherapy (WBC) on the level of CAT, GPx and SOD in women with multiple sclerosis and healthy women. The consent of the Bioethics Committee at the Regional Medical Chamber in Krakow was obtained, and the trial was registered in the Australian New Zealand Clinical Trials Registry. Thirty people took part in the study: the study group (MS) and the control group (CONT). All subjects participated in 20 cryotherapy sessions. Venous blood was collected for analysis before the WBC session and after 20 sessions. There were no changes in the examined parameters (CAT, GPx, SOD) after using WBC in the MS or control groups. There were also no differences between the groups in the first or the last study. There were no adverse changes in the parameters tested - WBC appeared to be a safe form of therapy, although the mechanisms of hypothermic protection are not fully understood.

The Effect of Acute Caffeine Intake on Resistance Training Volume, Prooxidant-Antioxidant Balance and Muscle Damage Markers Following a Session of Full-Body Resistance Exercise in Resistance-Trained Men Habituated to Caffeine.

No previous study has analyzed the impact of caffeine intake on prooxidant-antioxidant balance and muscle damage following resistance exercise. The aim of this study was to determine the effect of 3 mg/kg of caffeine on the number of repetitions and the prooxidant-antioxidant balance and muscle damage after a session of full-body resistance exercise. Ten resistance-trained men habituated to caffeine participated in a randomized, crossover and double-blind experiment. Each participant performed two identical resistance training sessions after the intake of 3 mg/kg of caffeine or a placebo. Blood was collected before and 60 min after substance intake, just after exercise, 60 minutes after exercise, and 24 hours after testing to evaluate the activity of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, catalase), non-enzymatic antioxidants (reduced glutathione, uric acid) levels of oxidative stress markers (plasma malondialdehyde) and muscle damage markers (creatine kinase, lactate dehydrogenase). There were no significant differences between placebo and caffeine conditions in the total number of repetitions (180 ± 15 vs 185 ± 14 repetitions, respectively; p = 0.276; Effect size [ES] = 0.34), the total time under tension (757 ± 71 vs 766 ± 56 s, respectively; p = 0.709; ES = 0.14) or the rating of perceived exertion (13.8 ± 2.7 vs 14.7 ± 2.7 a.u., respectively; p = 0.212; ES = 0.32). Reduced glutathione concentration obtained 1 hour after exercise was higher with caffeine than with placebo (p = 0.047), without significant difference between conditions for any other prooxidant-oxidant or muscle damage marker at any time point (p > 0.050 for all). The oral intake of 3 mg/kg of caffeine by resistance-trained men habituated to caffeine did not enhance the number of repetitions during a medium load full-body resistance training session to failure and had a minimal impact on the prooxidant-antioxidant balance and muscle damage. The study was registered prospectively at ClinicalTrials.gov with the following ID: NCT05230303.

Comparison of selected prooxidant-antioxidant balance and bone metabolism indicators and BDNF levels between older women with different levels of physical activity.

BACKGROUND: Given a lack of studies precisely indicating how many steps elderly people should take daily for their antioxidant defence, bone metabolism, and cognitive abilities to improve, our study set out to compare the selected antioxidant, prooxidant, bone turnover, and BDNF indicators between elderly women differing in physical activity (PA) measured by the daily number of steps. METHODS: The PA levels of 62 women aged 72.1 ± 5.4 years were assessed based on their daily number of steps and then were used to allocate the participants to three groups: group I (n = 18; <5,000 steps a day); group II (n = 22; from 5,000 to 9,999 steps a day); and group III (n = 22; ≥10,000 steps a day). Blood samples were collected from the participants in early morning hours and subjected to biochemical analysis for prooxidant-antioxidant balance indicators (SOD, CAT, GPx, GR, GSH, UA, MDA and TOS/TOC), bone metabolism indicators (Ca, 25-OH vitamin D, osteocalcin, CTX-I, and PTH), and BDNF levels. RESULTS: The groups were not statistically significantly different in the activity of SOD, CAT, GPx, and GR, but their concentrations of GSH (H = 22.10, p < 0.001) and UA (H = 12.20, p = 0.002) proved to be significantly associated with the groups' daily PA. The between-group differences in the concentrations of MDA and TOS/TOC were not significant, with both these indicators tending to take higher values in group I than in groups II and III. Significant differences between the groups were established for the concentrations of 25-OH vitamin D (H = 24.21, p < 0.001), osteocalcin (H = 7.88, p = 0.019), CTX-I (H = 12.91, p = 0.002), and BDNF (H = 14.47, p = 0.001), but not for Ca and PTH. CONCLUSIONS: Significantly higher concentrations of GSH, slightly lower oxidative stress indicators, significantly higher BDNF levels, and moderately better bone turnover indicators and resorption markers in the group taking more than 5,000 steps a day suggest that this level of PA can promote successful aging. More research is, however, needed to confirm this finding.

Comparison of the effects of six-week time-restricted eating on weight loss, body composition, and visceral fat in overweight older men and women.

The aim of this study was to determine the effectiveness of a six-week time-restricted eating (TRE) intervention in reducing body weight, fat loss, and visceral fat in overweight, older adult men and women (age range = 65-74 years). Another objective was to determine the feasibility of widespread use of TRE in older women and men. The study randomly assigned 116 healthy, non-smoking participants to one of two conditions: TRE or educational control participants. Participants in the TRE group were instructed to not consume calorie containing beverages or food for 16 h per day, from 8:00 pm to 12:00 pm. Participants in the control group were instructed to follow a meal plan based on their previous habits. The changes in body weight and body composition were determined using a SECA mBCA 515 analyzer. The six-week TRE intervention resulted in a significant decrease in body weight in both men and women (-1.8 kg and-1.3 kg, respectively; p = 0.03). In men, a significant decrease in visceral fat mass (-0.54 l; p ≤ 0.001) and waist circumference (-2.9 cm; p ≤ 0.015) was observed. No significant changes in either visceral fat or waist circumference were observed in women. Additionally, no change in skeletal muscle mass was observed in either the control or TRE group. More than 99 % of female and 98 % of male participants were able to adhere to the prescribed time-restricted eating (16/8) plan, suggesting that this dietary approach could have beneficial effects on the body composition of overweight older men and may also reduce body weight in overweight, older women.

Effect of Whole-Body Vibration on Serum Levels of Brain Derived Neurotrophic Factor and Cortisol in Young, Healthy Women.

Vibration exercises on a platform (whole-body vibration, WBV), widely used in rehabilitation, sports medicine, and fitness, is an alternative to strength effort. The presented study assessed the effect of a 12-week cycle of vibration training on the serum concentrations of brain-derived neurotrophic factor (BDNF) and cortisol in young women (trial ID: ACTRN 12621000114842). Volunteers were assigned to three groups: performing exercises on a vibrating platform (n = 17), performing identical exercises without a platform (n = 12), and passive control group (n = 17). The concentration of BDNF and cortisol was assessed four times: before the first training session, 5 min after it, also before, and 5 min after the last training session. There were no statistically significant changes in the groups or among groups for both substances. WBV in the presented form did not increase the secretion of BDNF and is not a stressful stimulus.

Effects of Elevated Body Temperature on Selected Physiological Indices and Thermal Stress in Athletes and Non-Athletes.

The purpose of this study was to determine the effects of active and passive overheating. A group of athletes (A) and non-athletic men (N) underwent an exercise stress test at elevated ambient temperature and sauna bathing until an increase in rectal temperature of 1.2°C was observed. It was shown that group A performed physical exercise for a longer period of time, which elicited significantly higher amounts of work performed in the stress test. Both forms of overheating caused a significant decrease in BM and a significant change in plasma volume, while greater dehydration was observed after active overheating. Changes observed in group A were higher than in group N. MCV levels were initially higher in group A. The levels in both groups decreased after sauna bathing, although in non-athletes the decrease was greater. Both forms of overheating increased Hb, HCT, and SBP, while only the non-athletic group showed a decrease in DBP after the exercise stress test. However, a decrease in DBP was observed in both groups after sauna bathing. The PSI increased after both tests, yet to a higher extent after the stress test than after sauna bathing. The PSI was negatively correlated with VO2max in both groups. The increase in cortisol concentration was higher after sauna bathing. There was a correlation between cortisol levels and the work performed during the stress test in group A. Endurance training resulted in more efficient thermoregulatory mechanisms in athletes.

Differences in the Pro/Antioxidative Status and Cellular Stress Response in Elderly Women after 6 Weeks of Exercise Training Supported by 1000 mg of Vitamin C Supplementation.

Vitamin C supplementation and exercise influence pro/antioxidative status and the cellular stress response. We tested the effects of exercise training for 6 weeks, supported by 1000 mg of vitamin C supplementation in elderly women. Thirty-six women were divided into two groups: a control group (CON) (n = 18, age 69.4 ± 6.4 years, 70.4 ±10.4 kg body mass) and a supplemented group (SUPP) (n = 18, aged 67.7 ± 5.6 years, body mass 71.46 ± 5.39 kg). Blood samples were taken twice (at baseline and 24 h after the whole period of training), in order to determine vitamin C concentration, the total oxidative status/capacity (TOS/TOC), total antioxidant status/capacity (TAS/TAC), and gene expression associated with cellular stress response: encoding heat shock factor (HSF1), heat shock protein 70 (HSPA1A), heat shock protein 27 (HSPB1), and tumor necrosis factor alpha (TNF-α). We observed a significant increase in TOS/TOC, TAS/TAC, and prooxidant/antioxidant balance in the SUPP group. There was a significant decrease in HSPA1A in the CON group and a different tendency in the expression of HSF1 and TNF-α between groups. In conclusion, vitamin C supplementation enhanced the pro-oxidation in elderly women with a normal plasma vitamin C concentration and influenced minor changes in training adaptation gene expression.

Effect of 6-week curcumin supplementation on aerobic capacity, antioxidant status and sirtuin 3 level in middle-aged amateur long-distance runners.

BACKGROUND: The study was undertaken to evaluate the effect of 6-week supplementation with a daily dose of 2g of curcumin on VO2max and prooxidant/antioxidant homeostasis in middle-aged amateur long-distance runners during the preparatory period of the macrocycle. METHODS: Thirty runners were randomly assigned to a placebo group (PL) and a curcumin-supplemented group (CU). Their VO2max was assessed before supplementation and after 6 weeks of supplementation. Venous blood samples were collected from the participants at rest, immediately after exercise, and after 1h of recovery to evaluate the activity of antioxidant enzymes (SOD, CAT, GPx), non-enzymatic antioxidants (GSH, UA) and sirtuin 3 level (SIRT 3), as well as the levels of oxidative stress markers (TOS/TOC, MDA, and 8-OHdG) and muscle damage markers (CK, LDH, and Mb). RESULTS: VO2max, the activity of enzymatic antioxidants, the concentrations of non-enzymatic antioxidants, the levels of oxidative stress markers, and the levels of muscle damage markers did not change significantly in the CU group over 6 weeks of supplementation with curcumin. However, the resting concentration of SIRT 3 was found to be significantly higher (p ≤ 0.05) compared with pre-supplementation. CONCLUSION: Curcumin supplementation does not have a significant effect on VO2max and prooxidant/antioxidant homeostasis in runners.

The effect of calorie restriction on the anthropometric parameters, HOMA-IR index, and lipid profile of female office workers with overweight and obesity: a preliminary study.

OBJECTIVES: This study evaluates the effect of a 3-month calorie restriction (CR) without snacking on the anthropometric parameters, Homeostatic Model Assesment of Insulin Resistance (HOMA-IR), and lipid profiles of female office workers with overweight or obesity, whose physical activity was limited during the COVID-19 pandemic lockdown. MATERIAL AND METHODS: Forty-eight women aged 20-38 years (28.9±5.24) with low physical activity levels were divided into a non-snacking (NS) group (N = 21) and a snacking (S) group (N = 27) prior to the dietary intervention. Their daily energy intake during the intervention was lowered by 30% compared with the baseline level, and the proportion of polyunsaturated fatty acids and fiber in their diet was increased (to >30 g/day). The proportion of saturated fatty acids and simple carbohydrates was also reduced. The study participants were assessed at the baseline and post-intervention for anthropometric variables (body weight, body fat percentage BMI, waist circumference, hip circumference, waist-to-hip ratio) and the concentrations of insulin, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C). Moreover, the values for HOMA-IR, the atherogenic index of plasma (AIP), and the ratios of TC/HDL-C, TG/HDL-C, and LDL-C/HDL-C were calculated. RESULTS: All anthropometric parameter values obtained post-intervention were lower than the baseline in both groups. The serum insulin concentration and HOMA-IR decreased respectively by an average of 6% and 25% in the NS group and 37% and 45% in the S group. The lipid profiles of all participants improved significantly, with the LDL-C concentration showing a more promising trend in the S group (decrease by 27%) than in the NS group (17%). CONCLUSIONS: The study showed that CR improved the anthropometric parameters, HOMA-IR index, and lipid profiles of all participants. Int J Occup Med Environ Health. 2022;35(6):693-706.

Effect of a six-week times restricted eating intervention on the body composition in early elderly men with overweight.

The main aim of the study was to determine the effectiveness of time-restricted eating (TRE) in reducing body fat and lowering body mass index in early elderly men with overweight (65-74 years). An additional goal was to determine the feasibility of applying TRE for extensive use in elderly men. This study included a group of 46 healthy men (EXP = 23 persons, CON = 23 persons). The six-week intervention in the experimental group involved complete abstinence from food intake for 16 h per day, from 08:00 to 12:00 p.m. After the intervention, the body weight decreased in the EXP group (- 1.92 kg) with a 95% CI (1.14-2.70) compared to the CON group. There was also a decrease in the Visceral fat mass (- 0.64 l) with 95% CI (0.46-0.82) and in the waist circumference (- 3.11 cm) with 95% CI (1.89-4.33) in the EXP group compared to the CON group. The skeletal muscle mass did not change significantly. There was no significant change in the control group, either. The application of TRE in early elderly overweight men resulted in positive changes in body composition and visceral fat. All participants succeed in the prescribed diet plan, which shows that TRE is easy to maintain for early elderly overweight men and may become an essential obesity treatment tool in these age groups.

Physiological and Somatic Principal Components Determining VO2max in the Annual Training Cycle of Endurance Athletes.

The purpose of the study was to assess the impact of training on the physiological variables achieved during the test effort in the macrocycle of road cyclists and their use in the maximal oxygen uptake (VO2max) prediction at individual training stages in the VO2max test. Nine well-trained male cyclists (age 25.6 ± 5.2 years and body weight 72.4 ± 7.35 kg) participated in the study and each phase of the macrocycle was followed by a time to exhaustion test (TTE) on the bicycle ergometer. The research showed that training loads significantly influence the maximum power (PPO), ventilation (VE) in the preparatory period (T1), time of the test (TTmax) at the start of the competition period (T2), percentage of body fat in total body weight (%FAT) and skeletal muscle mass (MMS) during the competition period (T3). Of the 16 variables taken for the analysis of the principal components (PC), the regression model determined one principal variable responsible for VO2max in the training macrocycle of cyclists, the relative value of maximum power (PPORV) and the accompanying variables in individual periods: breathing frequency (BF), delta blood lactate concentration (ΔLA), body fat (FAT) and MMS. Determining PC influencing the exercise capacity can be crucial in achieving the intended goals by athletes. Monitoring these indicators can help protect the health of professional athletes and provide guidelines in the training process, stimulate the body properly while protecting against overtraining.

Changes in Skin Microcirculation Resulting from Vibration Therapy in Women with Cellulite.

BACKGROUND: Cellulite is a cosmetic defect that affects over 80% of post-pubertal women. One of its pathomechanisms involves microvascular dysfunction. It has been suggested that vibration is a physical stimulus that may improve circulation in the skin and muscles. The aim of this study was to evaluate the effect of local vibration on cutaneous microcirculation and on eliminating the symptoms of cellulite in women. METHODS: A total of 57 healthy women with at least grade 1 cellulite were recruited and divided into four groups differing by treatment time (30' or 60') and position (sitting or lying) during the vibration treatments. Participants took part in 15 vibrotherapy sessions. Body composition, selected circumferences, cellulite grade, and thermographic images of buttocks and thighs were recorded. RESULTS: Significant changes in skin temperature were observed in both studied areas after the first and last treatments in each group. A significant decrease in cellulite grade was observed after a series of treatments. The strongest effects were observed for the sitting position with a treatment time of 60 min. CONCLUSION: Vibration treatment improves microcirculation in cellulite-affected areas. Over time, no adaptation was observed, and subsequent treatments maintained the beneficial effects. Extending the treatment time increased its influence on the microcirculation in the skin.

Occupational and leisure time physical activity of territorial army soldiers during the COVID-19 pandemic in the context of their perceived work ability.

OBJECTIVES: Physical activity (PA) is important for the prevention and management of numerous diseases and may have a positive effect on ability to work. The study aimed to assess the level of occupational and leisure time PA of soldiers during the COVID-19 pandemic and to explore whether there was a relationship between PA and perceived work ability. MATERIAL AND METHODS: The study involved 305 men and 68 women who were territorial army soldiers aged 18-55 (M±SD 32.9±9.01). The Seven-Day Physical Activity Recall (SDPAR) and the Work Ability Index (WAI) were used. RESULTS: The level of self-reported PA for the studied soldiers was relatively high; 80% of them met the recommendations of the WHO and were characterized by having a good (60%) or excellent (20%) WAI status. The level of occupational PA of male soldiers was higher than the level of leisure time PA, and they indicated higher levels of occupational PA and leisure time PA during the workweek than the weekend. CONCLUSIONS: Current work ability in comparison to the best in life and work ability related to the physical requirements of the work were positively correlated with leisure time PA. Work ability related to physical requirements was also positively correlated with occupational and total PA, and work ability related to mental requirements was positively correlated with total PA. The study supports the relationship between PA and several aspects of work ability. Int J Occup Med Environ Health. 2022;35(3):327-37.

Local Vibration Reduces Muscle Damage after Prolonged Exercise in Men.

Prolonged exercise can lead to muscle damage, with soreness, swelling, and ultimately reduced strength as a consequence. It has been shown that whole-body vibration (WBV) improves recovery by reducing the levels of stress hormones and the activities of creatine kinase (CK) and lactate dehydrogenase (LDH). The aim of the study was to demonstrate the effect of local vibration treatment applied after exercise on the level of selected markers of muscle fiber damage. The study involved 12 untrained men, aged 21.7 ± 1.05 years, with a VO2peak of 46.12 ± 3.67 mL·kg-1·min-1. A maximal intensity test to volitional exhaustion was performed to determine VO2peak and individual exercise loads for prolonged exercise. The subjects were to perform 180 min of physical effort with an intensity of 50 ± 2% VO2peak. After exercise, they underwent a 60 min vibration treatment or placebo therapy using a mattress. Blood samples were taken before, immediately after the recovery procedure, and 24 h after the end of the exercise test. Myoglobin (Mb) levels as well as the activities of CK and LDH were recorded. Immediately after the hour-long recovery procedure (vibration or placebo), the mean concentrations of the determined indices were significantly different from baseline values. In the vibration group, significantly lower values of Mb (p = 0.005), CK (p = 0.030), and LDH (p = 0.005) were seen. Differences were also present 24 h after the end of the exercise test. The results of the vibration group compared to the control group differed in respect to Mb (p = 0.002), CK (p = 0.029), and LDH (p = 0.014). After prolonged physical effort, topical vibration improved post-workout recovery manifested by lower CK and LDH activity and lower Mb concentration compared to a control group.

Musculoskeletal disorders and the physical activity of territorial army soldiers during the COVID-19 pandemic.

BACKGROUND: The aim of this study was to assess the occurrence of self-reported musculoskeletal disorders (MSD) among Polish territorial army soldiers during the COVID-19 pandemic and to investigate whether there was a relationship between occupational physical activity (OPA), leisure time physical activity (LTPA), and MSD. METHODS: The study used a cross-sectional design with a sample of 373 territorial army soldiers ages 18-55 who had not previously suffered from COVID-19 and were not convalescents. The symptoms prevalence data was collected using the standardized Nordic Musculoskeletal Questionnaire. OPA and LTPA data was collected using the Seven-Day Physical Activity Recall (SDPAR). RESULTS: The OPA, LTPA, and total physical activity (PA) among the studied soldiers was very diverse and the mean level of PA was relatively high. A total of 56 and 40% of territorial army soldiers had experienced pain or other discomfort in one or more of nine body regions during the past 12 months and during the past 7 days, respectively. The most common MSD among Polish territorial army soldiers were low back pain, followed by pain in the neck and knees. CONCLUSIONS: The study revealed that the OPA of the studied soldiers, especially vigorous-intensity and high vigorous-intensity OPA, was associated with a higher prevalence of MSD in several regions of the body, i.e. the lower back, elbows, wrists or hands, hips or thighs, and ankles or feet. Along with the increase in energy expenditure on total PA, a greater percentage of respondents experienced low back pain. Vigorous and high vigorous-intensity PA may contribute to the occurrence of MSD.

Blood serum denaturation profile examined by differential scanning calorimetry reflects the effort put into ultramarathon by amateur long-distance runners.

The impact of participation in the ultramarathon on the health and mental and physical condition is very complex. Undoubtedly, exercise brings many benefits but also involves health risks. Especially such an extreme effort as the one associated with finishing the ultramarathon run, can be dangerous to the health of the runner. With the variety of possible biomarkers of excessive fatigue that threaten health and life, a question arises which of them are the best and which should be considered in amateur long-distance runners showing particularly high individual variability. In this study differential scanning calorimetry (DSC) has been applied to show the overall effect of the 12-h run on blood sera of participants. Serum samples were obtained from the blood of ten male amateur long-distance runners, collected before and immediately after the run. Distinct changes in the shape of DSC curves have been observed for serum after finishing the run relative to pre-race serum. Statistically significant differences between stages "before" and "after" ultramarathon running have been found for parameters of the endothermic transition associated with denaturation of serum proteins. An increase in the temperature (from 70.9 ± 0.9 to 75.8 ± 2.9 °C) and excess heat capacity (from 0.859 ± 0.201 to 1.102 ± 0.226 Jg-1 °C-1) at peak maximum, the enthalpy of serum denaturation (from 18.55 ± 6.52 to 22.08 ± 5.61 Jg-1) and the first moment of the thermal transition with respect to the temperature (from the value of 67.0 ± 2.1 to 72.6 ± 2.1 °C) has been observed. These results show a clear impact of running an ultramarathon on the participant's blood serum.

Changes in blood antioxidant status in American football players and soccer players over a training macrocycle.

BACKGROUND: The effectiveness of sport training programs should be assessed regularly against biochemical indices. This study assesses changes in the antioxidant status indices in American football players (AF) and soccer players (SP) over a training macrocycle. METHODS: The study was carried out with Poland's American Football League players (AF, n = 11, age 24.0 ± 3.7 years) and first-league soccer players (SP, n = 11, age 26.5 ± 3.8 years). Resting venous blood samples were collected from the players at the beginning of the three periods (preparatory, competition, and transition) making up the training macrocycle to determine the activity levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), glutathione reductase (GR), creatine kinase (CK), and lactate dehydrogenase (LDH), as well as the concentrations of non-enzymatic antioxidants (uric acid-UA and glutathione-GSH) and the levels of malondialdehyde (MDA). RESULTS: The period effect on SOD (p < 0.001), CAT (p < 0.05), GPx (p < 0.05), GSH (p < 0.0001) and UA (p < 0.0001), and the group × period interaction effect on SOD, CAT and GPx (p < 0.05), GSH (p < 0.001), and UA (p < 0.01) proved to be significant. Also significant were the group effect on MDA (p < 0.001) and LDH (p < 0.0001) and the period effect on MDA (p < 0.01) and LDH (p < 0.001). The activity of SOD and CAT and the concentration of GSH were higher in both AF (12%, 2%, and 15%, respectively) and SP (33%, 10%, and 42%) at the start of the competition period than in the preparatory period, but the concentration of MDA and the activity of CK and LDH was lower (0.8%, 29%, 5% (AF) and 2%, 11%, 5% (SP). The highest activity of GPx and LDH and the greatest concentrations of UA and MDA occurred in the early transition period. CONCLUSION: The study revealed an association between American footballers' and soccer players' training loads in the preparatory period and moderate improvements in their blood antioxidant status at the beginning of the competition period.

The Effect of Medium-Term Sauna-Based Heat Acclimation (MPHA) on Thermophysiological and Plasma Volume Responses to Exercise Performed under Temperate Conditions in Elite Cross-Country Skiers.

The influence of a series of ten sauna baths (MPHA) on thermophysiological and selected hematological responses in 14 elite cross-country skiers to a submaximal endurance exercise test performed under thermoneutral environmental conditions was studied. Thermal and physiological variables were measured before and after the exercise test, whereas selected hematological indices were studied before, immediately after, and during recovery after a run, before (T1) and after sauna baths (T2). MPHA did not influence the baseline internal, body, and skin temperatures. There was a decrease in the resting heart rate (HR: p = 0.001) and physiological strain (PSI: p = 0.052) after MPHA and a significant effect of MPHA on systolic blood pressure (p = 0.03), hematological indices, and an exercise effect but no combined effect of treatments and exercise on the tested variables. A positive correlation was reported between PSI and total protein (%ΔTP) in T2 and a negative between plasma volume (%ΔPV) and mean red cellular volume (%ΔMCV) in T1 and T2 in response to exercise and a positive one during recovery. This may suggest that MPHA has a weak influence on body temperatures but causes a moderate decrease in PSI and modifications of plasma volume restoration in response to exercise under temperate conditions in elite athletes.