Effects of two low-volume high-intensity interval training protocols in professional soccer: sprint interval training versus small-sided games.

BACKGROUND: The programming of training protocols within a high-intensity interval training (HIIT) framework with appropriate analysis of total training load could deliver optimal training adaptations. This study aims to compare the efficiency of two low-volume HIIT protocols integrated with the regular training regime in professional soccer players. METHODS: Twenty-five participants aged 18.4-29.7 years were randomly assigned to one of two interventions involving straight-line sprint interval training (SIT, N.=13) or small-sided games (SSG, N.=12). Periodization was divided into two 3-week phases concluded by a 7-day taper. SIT first involved two-session·week-1 of one set of 10·45-s sprints (at maximal intensity) and then three-session·week-1 of two sets of 10·30-s sprints with a 0.75:1 and 1:1 recovery interval (slow running and stretching exercises), respectively. SSG in the first phase involved 5·3-min games of 4 vs. 4 and in the second phase 4·4-min games of 2 vs. 2 with 3-min recovery (practice drills at 60-70% HRmax). Training load was controlled via session-RPE and HR-based methods. Pre- and postintervention testing included: countermovement jump height, 5-m and 30-m sprints performance, anaerobic power by the 10-s Wingate Anaerobic Test, maximal oxygen uptake (V̇O2max) and blood lactate concentration (BLa-) determined by incremental exhaustive running test. RESULTS: Two-way ANOVA showed group×time interaction effects for the 30-m sprint time (F(1,23)=3.023; P=0.049; η2 P=0.116), BLa- (F(1,23)=5.250; P=0.031; η2 P=0.185), and V̇O2max (F(1,23)=4.648, P=0.044; η2 P=0.157). SIT elicited greater enhancements in anaerobic performance (30-m sprint time and BLa-), while SSG induced larger improvements in V̇O2max. CONCLUSIONS: Comparable effects of SIT and SSG protocols were noted, however the aerobic capacity benefits provided by SSG warrant this HIIT protocol as a highly recommended training modality in the professional soccer.

The Influence of Ambient Temperature Changes on the Indicators of Inflammation and Oxidative Damage in Blood after Submaximal Exercise.

Physical activity has a positive effect on human health and well-being, but intense exercise can cause adverse changes in the organism, leading to the development of oxidative stress and inflammation. The aim of the study was to determine the effect of short-term cold water immersion (CWI) and a sauna bath as methods of postexercise regeneration on the indicators of inflammation and oxidative damage in the blood of healthy recreational athletes. Forty-five male volunteers divided into two groups: 'winter swimmers' who regularly use winter baths (n = 22, average age 43.2 ± 5.9 years) and 'novices' who had not used winter baths regularly before (n = 23, mean age 25 ± 4.8 years) participated in the study. The research was divided into two experiments, differing in the method of postexercise regeneration used, CWI (Experiment I) and a sauna bath (Experiment II). During Experiment I, the volunteers were subjected to a 30-min aerobic exercise, combined with a 20-min rest at room temperature (RT-REST) or a 20-min rest at room temperature with an initial 3-min 8 °C water bath (CWI-REST). During the Experiment II, the volunteers were subjected to the same aerobic exercise, followed by a RT-REST or a sauna bath (SAUNA-REST). The blood samples were taken before physical exercise (control), immediately after exercise and 20 min after completion of regeneration. The concentrations of selected indicators of inflammation, including interleukin 1ß (IL-1ß), interleukin 6 (IL-6), interleukin 8 (IL-8), interleukin 8 (IL-8), interleukin 10 (IL-10), transforming growth factor ß1 (TGF-ß1) and tumor necrosis factor α (TNF-α), as well as the activity of indicators of oxidative damage: α1-antitrypsin (AAT) and lysosomal enzymes, including arylsulfatase A (ASA), acid phosphatase (AcP) and cathepsin D (CTS D), were determined. CWI seems to be a more effective post-exercise regeneration method to reduce the inflammatory response compared to a sauna bath. A single sauna bath is associated with the risk of proteolytic tissue damage, but disturbances of cellular homeostasis are less pronounced in people who regularly use cold water baths than in those who are not adapted to thermal stress.

Protective Effects of Exercise Become Especially Important for the Aging Immune System in The Covid-19 Era.

Aging is a complex, multietiological process and a major risk factor for most non-genetic, chronic diseases including geriatric syndromes that negatively affect healthspan and longevity. In the scenario of "healthy or good aging", especially during the COVID-19 era, the proper implementation of exercise as "adjuvant" or "polypill" to improve disease-related symptoms and comorbidities in the general population is a top priority. However, there is still a gap concerning studies analyzing influence of exercise training to immune system in older people. Therefore, the aim of this review is to provide a brief summary of well-established findings in exercise immunology and immunogerontology, but with a focus on the main exercise-induced mechanisms associated with aging of the immune system (immunosenescence). The scientific data strongly supports the notion that regular exercise as a low-cost and non-pharmacological treatment approach, when adjusted on an individual basis in elderly, induce multiple rejuvenating mechanisms: (1) affects the telomere-length dynamics (a "telo-protective" effect), (2) promote short- and long-term anti-inflammatory effects (via e.g., triggering the anti-inflammatory phenotype), 3) stimulates the adaptive immune system (e.g., helps to offset diminished adaptive responses) and in parallel inhibits the accelerated immunosenescence process, (4) increases post-vaccination immune responses, and (5) possibly extends both healthspan and lifespan.

Effects of Intensity Modulated Total-Body Circuit Training Combined with Soccer Training on Physical Fitness in Prepubertal Boys after a 6-Month Intervention.

The purpose of this study was to examine the effects of a 6-month high- or moderate-intensity total-body circuit training (CT) program on physical fitness in prepubertal soccer players. Sixty-seven prepubertal boys with a mean age of 11.2 ± 0.7 years completed the study. Participants from a soccer academy were randomly assigned either to a high-intensity CT group (HCT, n = 22) or a moderate-intensity CT group (MCT, n = 24). A control group (CON, n = 21) comprised age-matched individuals who were not involved in any regular training regime. CT protocols were included in the experimental group's training sessions 3 times per week over 24 weeks as part of their usual weekly training regime. Based on the HR zone method, CT protocols included high- or moderate-intensity (85-95% HRmax or 75-85% HRmax) series of 3 different sets of upper- and lower-body strength exercises with articular and muscular mobilization, all culminated with 40-m sprints. Physical fitness was evaluated by the Eurofit test which included the flamingo balance (FLB), plate tapping (PLT), sit-and-reach (SAR), standing broad jump (SBJ), handgrip (HG), sit-ups (SUP), bent arm hang (BAH), 10×5 m shuttle run (SHR), and the Physical Working Capacity test (PWC170). The two-way ANOVA indicated group×time interaction effects for 5 components: the largest was for the SBJ (F2,63 = 42.895, p < 0.001, η2 = 0.577), and the lowest for the SHR (F2,63 = 5.006, p < 0.01, η2 = 0.137) indicating better improvements in the HCT compared to the MCT group. Furthermore, for HCT and MCT groups the highest pre- to post-intervention percentage changes were for the FLB and the SAR, while in the CON group the changes of all physical fitness components were not significant (p < 0.05). In conclusion, the intensity-controlled total-body CT protocol incorporated into a standard soccer training program is effective for enhancement in physical fitness performance in prepubertal soccer players.

The Effects of Repeated Thermal Stress on the Physiological Parameters of Young Physically Active Men Who Regularly Use the Sauna: A Multifactorial Assessment.

The aim of this study was to determine the effects of thermal stress (TS) on changes in blood biochemical parameters and fluid electrolyte levels in young adult men with moderate and high levels of physical activity. Thirty men (22.67 ± 2.02 years) were exposed to four 12-min sauna sessions (temperature: 90-91 °C; relative humidity: 14-16%) with four 6-min cool-down breaks. The evaluated variables were anthropometric, physiological, and hematological characteristics. The mean values of HRavg (102.5 bpm) were within the easy effort range, whereas HRpeak (143.3 bpm) values were within the very difficult effort range. A significant increase was noted in pO2 (p < 0.001), total cholesterol (p < 0.008), HDL (p < 0.006) and LDL cholesterol (p < 0.007). Significant decreases were observed in the SBP (by 9.7 mmHg), DBP (by 6.9 mmHg) (p < 0.001), pH (p < 0.001), aHCO3- (p < 0.005), sHCO3- (p < 0.003), BE (ecf) (p < 0.022), BE (B), ctCO2 (for both p < 0.005), glucose (p < 0.001), and LA (p < 0.036). High 72-min TS did not induce significant changes in the physiological parameters of young and physically active men who regularly use the sauna, excluding significant loss of body mass. We can assume that relatively long sauna sessions do not disturb homeostasis and are safe for the health of properly prepared males.

The Effect of Submaximal Exercise Followed by Short-Term Cold-Water Immersion on the Inflammatory State in Healthy Recreational Athletes: A Cross-Over Study.

Cold-water immersion (CWI) after exercise is a method used by sportsmen to improve recovery. The aim of the study was to assess the effect of a 3 min CWI on the inflammatory state by measuring levels of interleukin 6 (IL-6), interleukin 10 (IL-10), tumor necrosis factor α (TNF-α), and transforming growth factor ß1 (TGF-ß1), and activities of α1-antitrypsin (AAT) and lysosomal enzymes, including arylsulfatase (ASA), acid phosphatase (AcP), and cathepsin D (CTS D), in the blood of healthy recreational athletes. Male volunteers (n = 22, age 25 ± 4.8 yr) performed a 30 min submaximal aerobic exercise, followed by a 20 min rest at room temperature (RT-REST) or a 20 min rest at room temperature with an initial 3 min 8 °C water bath (CWI-REST). Blood samples were taken at baseline, immediately after exercise, and after 20 min of recovery. The IL-6, IL-10, and TNF-α levels and the AAT activity increased significantly immediately after exercise. The IL-6 level was significantly higher after CWI-REST than after RT-REST. No changes in the activities of the lysosomal enzymes were observed. The effect of a 3 min CWI on the level of inflammatory markers during post-exercise recovery was limited. Thus, it might be considered as a widely available method of regeneration for recreational athletes.

Relationships Between Measures of Functional and Isometric Lower Body Strength, Aerobic Capacity, Anaerobic Power, Sprint and Countermovement Jump Performance in Professional Soccer Players.

The purpose of this study was to assess a wide range of physiological and performance variables and investigate whether and to what extent these variables are associated with each other in soccer. Twenty-five male soccer players (25.1 ± 4.56 years; body mass, 75.2 ± 5.92 kg; body height, 180.6 ± 5.45 cm) performed: 5- and 30-m sprints (T5m and T30m, respectively), 1-repetition-maximum (1RM) half squat, maximal voluntary isometric contraction (MVIC) of the knee extensors, countermovement jump (CMJ) to obtain vertical jump height (CMJheight) and power output (CMJpower), the 10-s Wingate Anaerobic Test (WAnT) to obtain peak power (Pmax), and the 20-m multi-stage shuttle run test (MST) to evaluate aerobic capacity. 1RM, MVIC, and Pmax were normalized to body mass. Large negative correlations were found between sprint times and 1RM half back squat/BM (r = -0.510 to -0.570, r2 = 0.260-0.325, both p < 0.01) and Pmax/BM (r = -0.501, r2 = 0.251, p < 0.01). T30m most strongly and negatively correlated with CMJheight (r = -0.744, r2 = 0.554, p < 0.001). WAnT-determined Pmax showed a very large correlation between absolute Pmax and knee-extensor MVIC (r = 0.827, r2 = 0.684, p < 0.001) and large correlations between absolute Pmax and 1RM half squat (r = 0.674, r2 = 0.454, p < 0.001) and CMJpower (r = 0.579, r2 = 0.335, p < 0.01). We also identified a large inverse relationship between CMJheight and T30m (r = -0.744, r2 = 0.554, p < 0.001) and large positive correlation between CMJheight and MVIC/BM (r = 0.702, p < 0.001). The results demonstrate that elite soccer players with greater lower body strength (quantified by the MVIC of the knee extensor and the 1RM half squat) show better sprint and CMJ performance, suggesting the incorporation of soccer-specific resistance training to develop lower body musculature and therefore maximize sprinting ability. The higher correlation coefficients found between T30m and the physiological and athletic measures compared with T5m promote the use of this sprint distance when assessing performance. The use of relative measures (normalized to body mass) is advisable when comparing strength variables with sprint and CMJ performance or anaerobic power. Considering the correlations of WAnT-determined Pmax versus CMJpower, coaches should administer tests that assess jumping and linear sprint performance rather than the cycling-specific WAnT.

The effects of a 6-month moderate-intensity Hatha yoga-based training program on health-related fitness in middle-aged sedentary women: a randomized controlled study.

BACKGROUND: There is paucity of data examining the effectiveness of long-term Hatha yoga-based (HY) programs focused on the health-related fitness (H-RF) of asymptomatic, sedentary women. The purpose of this study was to examine the effects of a 6-month HY-based training program on H-RF components in sedentary middle-aged women. METHODS: Eighty sedentary women were randomly assigned into either the HY group (HYG) (N.=42) or the control group (CG) (N.=38). The 6-month HYG program involved a progressive series of Vinyasa Flow poses performed 3 times/week for 60 minutes (40 minutes within the exercise zone of 60-75% HRmax). The CG participants did not undergo any physical training or education. Health-related fitness parameters included measures of pre- and post-training: body composition, muscular strength and maximal voluntary isometric torques of elbow flexors and knee extensors, cardio-respiratory fitness, lower back and hamstring flexibility and a static-dynamic balance. RESULTS: Two-way mixed design ANOVA revealed significant main effects for all the indicators of H-RF. Tukey post-hoc tests confirmed that the HYG demonstrated significant improvements in every variable tested. Examples of the benefits achieved include (all P<.001): an average loss of 1.03 kg and a 4.82% decrease in body fat, 14.6% and 13.1% gains in isometric strength of the knee extensors and elbow flexors respectively, an increase in relative VO2max of 6.1% (33.12±5.30 to 35.14±4.82 mL/kg/min), a 4-cm or 10.4% increase in their MSAR, and an average improved Balance Index of 5.6 mm/s. Reversely, the CG showed non-significant changes in H-RF variables (all P>0.05; percent range from -1.4% to 1.1%). CONCLUSIONS: By participating in a moderate-intensity 6-month HY-based training program, middle-aged women can significantly improve their HR-F status. The application of progressive target heart rate goals facilitated greater than expected improvements in cardio-respiratory fitness and improvements in body composition.

Effects of a 12-Month Complex Proprioceptive-Coordinative Training Program on Soccer Performance in Prepubertal Boys Aged 10-11 Years.

Boraczynski, MT, Sozanski, HA, and Boraczynski, TW. Effects of a 12-month complex proprioceptive-coordinative training program on soccer performance in prepubertal boys aged 10-11 years. J Strength Cond Res 33(5): 1380-1393, 2019-The aim was to examine the effects of a series of on-field proprioceptive-coordinative (P-C) exercises on motor performance (MP) in prepubertal soccer players. Fifty-three male soccer players aged 10.1-11.8 years were randomized among 2 experimental programs receiving P-C training (P-CT; n = 26) or regular training (RT; n = 27). A control group (C; n = 22) consisted of age-matched (10.3-11.9 years) cohorts not involved in any regular physical activity. Both experimental groups completed an identical 12-month comprehensive soccer program except training in P-CT was modified to substitute small-sided conditioning games with 24 multimode P-C exercises with modulated exercise intensity (every 8-9 weeks based on predicted maximal heart rate [HRmax]). Pre-, peri-, and posttraining measures included anthropometry and 5 tests assessing soccer-specific MP: movement rhythm (turning the ball backwards-T1), motor adaptation (running with the ball around poles-T2), spatial orientation (running to sequentially numbered balls-T3), balance (single-leg static balance-T4), and kinesthetic differentiation of movement (landing the ball on a 2 × 2 m sector-T5). Repeated-measures analysis of variance revealed no significance between-group differences for age, anthropometry, and body-fat percentage at baseline. Significant main effects for group (P-CT vs. RT) were found in all tests (T1-T5) and main effects for time (group P-CT) in T3-T5, whereas a significant group × time interaction was observed only in T4 (F = 2.98, p = 0.0204). Post hoc tests indicated that P-CT attained significantly better results than RT at peritraining (by 26.4%; p < 0.01) and posttraining (by 31.9%, p < 0.01). Modulated exercise intensity had little effect on soccer performance (T1-T3, T5). Based on the results, it is recommended that the training of young soccer players be supplemented with the bilateral balance exercises and games used in the study. Furthermore, the suitability of monitoring HR in P-C exercises targeting the analyzed MP skills is questionable.

The oxidant-antioxidant equilibrium, activities of selected lysosomal enzymes and activity of acute phase protein in peripheral blood of 18-year-old football players after aerobic cycle ergometer test combined with ice-water immersion or recovery at room temperature.

The goal of the study was to evaluate the effect of an aerobic exercise bout followed by ice-water immersion or recovery at room temperature on the redox state, activities of selected lysosomal enzymes and activity of α1-antitrypsin (AAT) in the blood of healthy sportsmen. Eleven amateur football players aged 18 were randomly assigned to two similar 30-min aerobic cycle ergometer tests followed by a recovery at room temperature (20 °C; Experiment 1) or ice-water immersion (3 °C, 5 min; Experiment 2). Peripheral blood was collected three times during both study experiments: before (baseline), as well as 20 and 40 min after the recovery or immersion. The concentrations of thiobarbituric acid reactive substances in blood plasma (plTBARS) and erythrocytes (erTBARS) were measured. The erythrocytic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) were also determined. In the blood serum, the activities of acid phosphatase (AcP), arylsulphatase (ASA), cathepsin D (CTS D) and AAT were evaluated. The activities of AcP, ASA, CTS D and AAT changed similarly during both experiments. The GPx activity decreased 40 min after the exercise/recovery compared to the baseline activity and was lower than 40 min after the exercise/immersion. The exercise followed by the recovery or immersion had no significant effect on the serum lysosomal and AAT activities in the studied men. The exercise/recovery reduced the hydrogen peroxide concentration in the men's erythrocytes, however the exercise/immersion demonstrated the opposite effect.

Temperamental Traits Versus Individual Physical Fitness Components and a Physical Activity Level.

The main aim of the study was to examine whether relationships exist between particular temperamental traits within the concept of Regulative Theory of Temperament and components of physical fitness, that are most crucial for success in sport. The research involved 108 individuals including 63 men (age 21.1 ± 1.6 yrs) and 45 women (age 20.7 ± 1.3 yrs). None of the respondents were professionally engaged in sport. Components of physical fitness included: aerobic capacity, strength, agility, static-dynamic balance and reaction time. The respondents also completed two questionnaires: the Formal Characteristics of Behaviour - Temperament Inventory and the International Physical Activity Questionnaire. The results indicate that the temperamental traits had average to poor correlations with the components of physical fitness, whereas more statistically significant correlations were observed in women. Negative correlations were obtained between emotional reactivity and agility, which was a result confirmed by previous research. All temperamental traits related with the energetic aspects of behaviour correlated with simple reaction time in women. Physical activity and aerobic capacity did not correlate with any of the studied traits. The results do not allow for any general conclusions to be drawn, but can serve as a reference point for future research on temperamental traits as delineated by Regulative Theory of Temperament and their relationship with the components of physical fitness.

Postexercise impact of ice-cold water bath on the oxidant-antioxidant balance in healthy men.

The aim of the study was to determine the effect of a 5 min head-out ice-cold water bath on the oxidant-antioxidant balance in response to exercise. The crossover study included the subjects (n = 24; aged 28.7 ± 7.3 years) who performed two identical stationary cycling bouts for 30 min and recovered for 10 min at room temperature (RT = 20°C; session 1) or in a pool with ice-cold water (ICW = 3°C, 5 min immersion; session 2). The concentration of thiobarbituric acid reactive substances (TBARS) in blood plasma (TBARSpl) and erythrocytes (TBARSer) and the erythrocytic activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were measured three times during each of the two study sessions: before the exercise (baseline) and 20 and 40 min after the appropriate recovery session. Lower concentration of TBARSpl 40 min after postexercise recovery in ICW was revealed as compared with that after recovery at RT (P < 0.05). Moreover, a statistically significant postexercise increase in the TBARSpl and TBARSer concentrations was found (P < 0.01 and P < 0.05, resp.). A short-term ice-cold water bath decreases postexercise lipid peroxidation.

Oxidation-reduction processes in ice swimmers after ice-cold water bath and aerobic exercise.

The effect of an ice-cold water (ICW) bath as a recovery intervention from aerobic exercise on the oxidant-antioxidant balance in healthy ice swimmers was determined. Twenty ice swimmers aged 31.2 ± 6.3 years performed a 30-min cycloergometer exercise test at room temperature (20°C, RT), followed by recovery at RT or in a pool of ice-cold water (ICW bath, 3°C, 5 min). Blood for laboratory assays was collected from the basilic vein two times: before the exercise (baseline) and 40 min after the RT or ICW recovery. The concentrations of plasma and erythrocytic thiobarbituric acid reactive substances (plTBARS and erTBARS, respectively), serum concentrations of 8-iso-prostaglandin F2α, 4-hydroxynonenal and malondialdehyde, along with the erythrocytic activities of catalase (CAT) and superoxide dismutase (SOD), as well as the serum level of total antioxidant capacity, were assessed. No statistically significant changes were observed. However, a statistically significant negative linear correlation between the erTBARS concentration and the SOD activity was found 40 min after the combination of exercise/RT recovery (r=-0.571, P<0.01). The baseline CAT and SOD activities were also linearly correlated (r=0.469, P<0.05). Both the 5-min ICW bath and the 30-min aerobic exercise have practically no impact on the oxidant-antioxidant balance in healthy ice swimmers.

Sauna-induced body mass loss in young sedentary women and men.

The aim of the study was to evaluate the relationship between body mass index (BMI) and body mass loss (BML) induced by thermal stress in a dry sauna. The study was conducted on a group of 674 sedentary students, 326 women and 348 men aged 19-20. The correlations between BMI scores and BML were determined. The subjects were placed in supine position in a dry sauna for two sessions of 10 minutes each with a 5-minute break. The influence of BMI on the amount of BML in the sauna was determined by nonlinear stepwise regression. The smallest BML was noted in underweight subjects; students with normal weight lost more weight, whereas the greatest BML was reported in overweight and obese subjects. Persons with a high BMI are at higher risk of dehydration, and they should pay particular attention to replenishing fluids during a visit to the sauna. The proposed equations for calculating BML based on a person's BMI can be useful in estimating the amount of fluids that should be replenished by both men and women during a visit to a dry sauna.

The effect of a single Finnish sauna bath after aerobic exercise on the oxidative status in healthy men.

BACKGROUND: The aim of this study was to determine the effect of Finnish sauna as a regeneration method post-exercise on the oxidant-antioxidant balance in healthy men. MATERIAL: 43 men aged 24.0 ± 4.3 years performed a 30-min aerobic exercise on a cycle ergometer and rested for 39 min at a room temperature (Day 1; 20°C) or in a sauna for post-workout recovery (Day 2; 90°C, air humidity 10%). Blood was taken 3 times during both study days: Before the exercise (baseline), 20 and 40 min after the recovery. Methods. The activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) was determined in the subjects' erythrocytes. The concentration of thiobarbituric acid reactive substances (TBARS) was measured both in plasma (TBARSpl) and in the erythrocytes (TBARSer). RESULTS: A 12.7% increase in the TBARSpl concentration versus the baseline was observed 40 min after the Finnish sauna (p < 0.01). The CAT activity observed 20 and 40 min after the sauna was also found higher by 8.1% and 8.9%, respectively, in comparison with the baseline (p < 0.05). In turn, the TBARSer concentration was lower by 17.5% 40 min after the recovery in the sauna, as compared with the TBARSer concentration 40 min after the recovery at the room temperature (p < 0.05). CONCLUSIONS: A single Finnish sauna bath as a source of free radicals per se is able to reduce oxidative stress induced by a 30-min aerobic exercise in healthy men.

Effects of thermal stress on the activity of selected lysosomal enzymes in blood of experienced and novice winter swimmers.

BACKGROUND: The aim of this study was to determine the effects of exposure to cold and heat on the activity of selected lysosomal enzymes as well as on the activity of the protease inhibitor, which are all considered to be markers of cellular damage. MATERIAL: Two groups of healthy volunteers were included in the study. The first group consisted of experienced winter swimmers who practiced bathing in ice-cold water once a week, while the other group was comprised of persons who had never taken part in winter swimming before. During the experiment all the participants bathed in a river with a water temperature of 0 °C. The same volunteers were later subjected to a sauna bath at an air temperature of 85 °C. METHODS: The activity of cathepsin D, alpha-1-antitrypsin, arylsulphatase and acid phosphatase was measured in the participant's blood serum. RESULTS: After exposure to cold water no changes in the parameters studied could be found. However, after the sauna an increase in the activity of arylsulphatase and alfa-1-antitrypsin accompanied by a decrease of cathepsin D activity could be observed. CONCLUSIONS: Winter swimming seems to have no effect on the activity of the lysosomal enzymes. By contrast, an increase of certain lysosomal enzymes after the sauna suggests that it may be deleterious to the lysosomal membranes. Furthermore it seems that regular winter swimming combined with sauna, according to hormesis theory, induces some adaptive response.