Low vitamin C values are linked with decreased physical performance and increased oxidative stress: reversal by vitamin C supplementation.

PURPOSE: It has been suggested that part of the failure of antioxidant supplementation to reduce oxidative stress and promote health is that it has been administered in humans with normal levels of antioxidants. METHODS: To test this hypothesis, we screened 100 males for vitamin C baseline values in blood. Subsequently, the 10 individuals with the lowest and the 10 with the highest vitamin C values were assigned in two groups. Using a placebo-controlled crossover design, the 20 selected subjects performed aerobic exercise to exhaustion (oxidant stimulus) before and after vitamin C supplementation for 30 days. RESULTS: The low vitamin C group had lower VO2max values than the high vitamin C group. Vitamin C supplementation in this group marginally increased VO2max. Baseline concentration of F2-isoprostanes and protein carbonyls was higher in the low vitamin C group compared to the high vitamin C group. Vitamin C supplementation decreased the baseline concentration of F2-isoprostanes and protein carbonyls in both groups, yet the decrease was greater in the low vitamin C group. Before vitamin C supplementation, F2-isoprostanes and protein carbonyls were increased to a greater extent after exercise in the high vitamin C group compared to the low vitamin C group. Interestingly, after vitamin C supplementation, this difference was narrowed. CONCLUSION: We show for the first time that low vitamin C concentration is linked with decreased physical performance and increased oxidative stress and that vitamin C supplementation decreases oxidative stress and might increase exercise performance only in those with low initial concentration of vitamin C.

Aerobic, resistance and combined training and detraining on body composition, muscle strength, lipid profile and inflammation in coronary artery disease patients.

Fifty-six elderly individuals diagnosed with coronary artery disease participated in the study and were divided into four groups: an aerobic exercise group, a resistance exercise group, a combined (aerobic + resistance) exercise group and a control group. The three exercise groups participated in 8 months of exercise training. Before, at 4 and at 8 months of the training period as well as at 1, 2 and 3 months after training cessation, muscle strength was measured and blood samples were collected. The resistance exercise caused significant increases mainly in muscle strength whereas aerobic exercise caused favourable effects mostly on lipid and apolipoprotein profiles. On the other hand, combined exercise caused significant favourable effects on both physiological (i.e. muscle strength) and biochemical (i.e. lipid and apolipoprotein profile and inflammation status) parameters, while the return to baseline values during the detraining period was slower compared to the other exercise modalities.

Passive smoking reduces and vitamin C increases exercise-induced oxidative stress: does this make passive smoking an anti-oxidant and vitamin C a pro-oxidant stimulus?

The current interpretative framework states that, for a certain experimental treatment (usually a chemical substance) to be classified as "anti-oxidant", it must possess the property of reducing (or even nullifying) exercise-induced oxidative stress. The aim of the study was to compare side by side, in the same experimental setup, redox biomarkers responses to an identical acute eccentric exercise session, before and after chronic passive smoking (considered a pro-oxidant stimulus) or vitamin C supplementation (considered an anti-oxidant stimulus). Twenty men were randomly assigned into either passive smoking or vitamin C group. All participants performed two acute eccentric exercise sessions, one before and one after either exposure to passive smoking or vitamin C supplementation for 12 days. Vitamin C, oxidant biomarkers (F2-isoprostanes and protein carbonyls) and the non-enzymatic antioxidant (glutathione) were measured, before and after passive smoking, vitamin C supplementation or exercise. It was found that chronic exposure to passive smoking increased the level of F2-isoprostanes and decreased the level of glutathione at rest, resulting in minimal increase or absence of oxidative stress after exercise. Conversely, chronic supplementation with vitamin C decreased the level of F2-isoprostanes and increased the level of glutathione at rest, resulting in marked exercise-induced oxidative stress. Contrary to the current scientific consensus, our results show that, when a pro-oxidant stimulus is chronically delivered, it is more likely that oxidative stress induced by subsequent exercise is decreased and not increased. Reversely, it is more likely to find greater exercise-induced oxidative stress after previous exposure to an anti-oxidant stimulus. We believe that the proposed framework will be a useful tool to reach more pragmatic explanations of redox biology phenomena.

Home-based tele-exercise training and physical activity during the COVID-19 pandemic in chronic kidney disease patients.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic and lockdown reduced physical activity levels in hemodialysis (HD) patients and kidney transplant recipients (KTRs). This study aimed to describe physical activity levels during lockdown and assess the effects of an online home-based exercise training program on physical activity levels in HD patients and KTRs. METHODS: Forty-five HD patients and thirty-five KTRs were divided into four groups: exercise groups 1 (ΕΧ-HD) and 2 (EX-KTR) followed a 4-month tele-exercise training program, while control groups received usual care. All participants at baseline and at the end of the study completed the International Physical Activity Questionnaire (IPAQ), while their daily physical activity levels were recorded via a step counting application. RESULTS: At the end of the study, the repeated measures analysis revealed a significant effect of time, group, and time-by-group interaction in the average steps per day, walking, and moderate activity for the exercise-HD group (p < 0.05). Similarly, the analysis revealed a notable effect of time, group, and time-by-group interaction in the exercise-KTR group in average daily steps, vigorous and walking activity (p < 0.05). Multiple regression analysis showed that the level of physical activity at the end of the study was related to the urban place of residence and the participation in the 4-month exercise program of both HD patients and KTRs. CONCLUSIONS: Participation in a tele-exercise training program led to favorable effects on physical activity levels both in HD patients and KTRs during lockdown.

Effects of Four Weeks of In-Season Pre-Workout Supplementation on Performance, Body Composition, Muscle Damage, and Health-Related Markers in Basketball Players: A Randomized Controlled Study.

This randomized, double-blinded, experimental study investigated the effects of a four-week daily pre-workout supplementation (200 mg caffeine, 3.3 g creatine monohydrate, 3.2 g ß-alanine, 6 g citrulline malate, and 5 g BCAA) vs. placebo (isocaloric maltodextrin) on anaerobic (jumping, sprinting, agility, and the running-based anaerobic sprint test: RAST) and aerobic (Yo-Yo intermittent recovery test level 1) performance, as well as on body composition and selective muscle damage/health-related blood markers in well-trained basketball players during the in-season period. Eighteen basketball players (age: 24.4 ± 6.3 years, height: 185.7 ± 8.0 cm, weight: 85.7 ± 12.8 kg, body fat: 16.5 ± 4.2%) were randomly assigned into two groups: pre-workout supplement (PWS, n = 10) or placebo (PL, n = 8). PWS consumption increased aerobic performance (PWS: 8 ± 6%; PL: -2 ± 6%; p = 0.004) compared to PL. A significant decrease was observed in peak (F = 7.0; p = 0.017), average (F = 10.7; p = 0.005), and minimum power (F = 5.1; p = 0.039) following 4 weeks of supplementation in both groups. No other significant changes were observed between groups (p > 0.05). In conclusion, the consumption of the current PWS over a four-week period appears to positively influence the aerobic performance of well-trained basketball players during the in-season period. However, it does not appear to mitigate the observed decline in anaerobic power, nor does it affect performance in jumping, sprinting, and agility, or alter body composition or selective muscle damage/health-related blood markers.

The Effects of Pilates Exercise Training Combined with Walking on Cardiorespiratory Fitness, Functional Capacity, and Disease Activity in Patients with Non-Radiologically Confirmed Axial Spondylitis.

The objective of the study was to examine the effects of Pilates exercise training combined with walking on cardiorespiratory fitness, functional capacity, and disease activity in patients with non-radiologically confirmed axial spondylitis (nr-axSpA). Thirty patients with nr-axSpA (seven women (90%), with a mean age of 46.07 ± 10.48 years old and C-reactive protein (CRP) 2.26 ± 2.14 mg/L) were randomly divided into two groups: A (n1 = 15 patients) and B (n2 = 15 patients). Group A followed a 6-month home-based Pilates exercise training program, while Group B remained untrained until the end of the study. A cardiopulmonary exercise test (CPET), timed up and go test (TUG), five times sit-to-stand test (5×STS), sit-and-reach test (SR), back scratch test for the right (BSR) and the left arm (BSL), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), and Ankylosing Spondylitis Disease Activity Score (ASDAS) were applied to all patients, both at the beginning and at the end of the study. After 6 months, Group A showed higher values in exercise time by 37.41% (p = 0.001), higher peak oxygen uptake (VO2peak) by 25.41% (p = 0.01), a higher ratio between oxygen uptake and maximum heart rate (VO2/HRmax) by 14.83% (p = 0.04), and higher SR by 18.70% (p = 0.007), while lower values were observed in TUG by 24.32% (p = 0.001), 5×STS by 12.13% (p = 0.001), BASDAI score by 20.00% (p = 0.04) and ASDAS score by 23.41% (p = 0.03), compared to Group B. Furthermore, linear regression analysis showed a positive correlation in Group A between BASDAI and 5×STS (r = 0.584, p = 0.02), BASDAI and TUG (r = 0.538, p = 0.03), and ASDAS and 5×STS (r = 0.538, p = 0.03), while a negative correlation was found between BASDAI and VO2peak (r = -0.782, p < 0.001), ASDAS and SR (r = -0.548, p = 0.03), and ASDAS and VO2peak (r = -0.659, p = 0.008). To sum up, cardiorespiratory fitness, functional capacity, and disease activity improved after a long-term Pilates exercise training program in patients with nr-axSpA.

Nutrition, body composition and physical activity have differential impact on the determination of lipidemic blood profiles between young females with different blood cholesterol concentrations.

INTRODUCTION: This cross-sectional study explored whether nutrition, body composition, and physical activity energy expenditure (PAΕΝ) have a differential impact on lipidemic blood profiles among young females with different blood cholesterol concentrations. METHODS: One hundred thirty-five young female students (N = 135) were allocated into three groups according to their blood cholesterol concentrations (Chol): (A) Normal [NL; Chol: < 200 mg·dL-1; n = 56 Age: 21.4 ± 2.6 yrs, Body Mass Index (BMI): 22.1 ± 2.0 kg·m-2], (B) Borderline (BL; Chol: ≥200 mg·dL-1 and <240 mg·dL-1; n = 44 Age: 21.6 ± 2.5 yrs, BMI: 24.2 ± 3.1 kg·m-2) and (C) High level (HL; Chol: ≥240 mg·dL-1; n = 35 Age: 22.5 ± 2.4 yrs, BMI: 28.9 ± 2.1 kg·m-2). Body composition [bioelectrical impedance analysis including lean body mass (LBM) and body fat mass], nutritional intake (recall questionnaire), daily physical activity energy expenditure through activity trackers and resting blood lipids concentrations were evaluated. RESULTS: Multiple linear regression analyses revealed that in the NL group, lean mass, daily PAΕΝ and daily energy balance were the determinant parameters of blood lipidemic profiles (B: -0.815 to 0.700). In the BL group, nutrition, body composition and daily physical activity energy expenditure exhibited similar impacts (B: -0.440 to 0.478). In the HL group, nutritional intake and body fat mass determined blood lipidemic profile (B: -0.740 to 0.725). CONCLUSION: Nutrition, body composition and daily PAΕΝ impact on blood lipids concentration is not universal among young females. In NL females, PAEN, energy expenditure and LBM are the strongest determinants of blood lipids, while in HL females, nutritional intake and body fat mass are. As PAΕΝ increases, the importance of nutrition and body fat decreases, and vice versa.

The Effect of Acute Pre-Workout Supplement Ingestion on Basketball-Specific Performance of Well-Trained Athletes.

A pre-workout supplement's (PWS; 200 mg caffeine, 3.3 g creatine monohydrate, 3.2 g ß-alanine, 6 g citrulline malate and 5 g branched chained amino acid (BCAA) per dose) acute effects on the alactic (jumping, sprinting, agility), lactic (Running-Based Anaerobic Sprint Test, RAST) and aerobic performance (Yo-Yo Intermittent Recovery Test Level 1, Yo-Yo IRL1 VO2max) of well-trained basketball players was investigated in this double-blind placebo-controlled study. Thirty players (age 18-31 years, height 166-195 cm, weight 70.2-116.7 kg, body fat 10.6-26.4%) were allocated to pre-workout (PWS, n = 15) or placebo (PL, n = 15) groups. Half of the participants in each group performed the evaluations without PWS or PL, while the rest consumed PWS or PL 30 min before the assessments (1st trial) and vice versa (2nd trial). Significant improvements in counter-movement jump (CMJ) (PWS: 4.3 ± 2.1%; PL: 1.2 ± 1.0%), agility (PWS: -2.9 ± 1.8%; PL: 1.8 ± 1.7%), RAST average (PWS: 18.3 ± 9.1%; PL: -2.2 ± 2.0%), minimum power (PWS: 13.7 ± 8.9%; PL: -7.5 ± 5.9%), and fatigue index (PWS: -25.0 ± 0.9%; PL: -4.6 ± 0.6%) were observed in the PWS group vs. the PL group (p < 0.05). No differences were found regarding sprinting, aerobic performance, and blood lactate concentrations. Thus, although players' alactic and lactic anaerobic performance could be improved, peak power, sprinting and aerobic performance are not.

Body Composition, Fasting Blood Glucose and Lipidemic Indices Are Not Primarily Determined by the Nutritional Intake of Middle-Aged Endurance Trained Men-Another "Athletes' Paradox"?

Systematic, regular high-volume endurance training induces significant metabolic adaptations in glucose and lipids metabolism, which seems to affect the negative impact of unhealthy nutrition, at least in animal models. The present study aimed to investigate the main determinants of body composition, blood glucose and lipids concentrations between middle-aged sedentary individuals (Sed) and well-trained endurance athletes (Run), both following an unhealthy high-fat diet. In thirty-five Sed (Age: 54.0 ± 6.6 yrs, Body Mass: 77.1 ± 10.5 kg, BMI: 31.3 ± 6.0 kg·m-2) and thirty-six Run (Age: 51.6 ± 5.2 yrs, Body Mass: 85.8 ± 3.4 kg, BMI: 23.2 ± 1.8 kg·m-2), body composition, nutritional intake, energy expenditure, resting metabolic rate (RMR), respiratory exchange ratio (RER), and blood glucose and lipids concentrations were evaluated. Multiple linear regression analyses revealed that body composition, blood glucose and lipids' concentrations in the Run group were primarily determined by the energy expenditure (B: -0.879 to -1.254), while in the Sed group, by their energy intake (B:-0.754 to 0.724). In conclusion, it seems that in well-trained endurance middle-aged athletes, body composition, blood glucose, and lipids concentrations seem to be determined by their training-induced daily energy expenditure and not by their nutritional intake per se. At the same time, nutrition is the primary determinant in aged-matched sedentary individuals, even if they both follow high-fat diets.

Effects of Cardiovascular, Resistance and Combined Exercise Training on Cardiovascular, Performance and Blood Redox Parameters in Coronary Artery Disease Patients: An 8-Month Training-Detraining Randomized Intervention.

It is well-documented that chronic/regular exercise improves the cardiovascular function, decreases oxidative stress and enhances the antioxidant capacity in coronary artery disease (CAD) patients. However, there is insufficient evidence regarding the chronic effects of different types of training and detraining on cardiovascular function and the levels of oxidative stress and antioxidant status in these patients. Therefore, the present study aimed at investigating the effects of cardiovascular, resistance and combined exercise training followed by a three-month detraining period, on cardiovascular function, physical performance and blood redox status parameters in CAD patients. Sixty coronary artery disease patients were randomly assigned to either a cardiovascular training (CVT, N = 15), resistance training (RT, N = 11), combined cardiovascular and resistance training (CT, N = 16) or a control (C, N = 15) group. The training groups participated in an 8-month supervised training program (training three days/week) followed by a 3-month detraining period, while the control group participated only in measurements. Body composition, blood pressure, performance-related variables (aerobic capacity (VO2max), muscle strength, flexibility) and blood redox status-related parameters (thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), reduced glutathione (GSH), oxidized glutathione (GSSG), catalase activity (CAT), protein carbonyls (PC)) were assessed at the beginning of the study, after 4 and 8 months of training as well as following 1, 2 and 3 months of detraining (DT). CVT induced the most remarkable and pronounced alterations in blood pressure (~9% reduction in systolic blood pressure and ~5% in diastolic blood pressure) and redox status since it had a positive effect on all redox-related variables (ranging from 16 to 137%). RT and CT training affected positively some of the assessed (TAC, CAT and PC) redox-related variables. Performance-related variables retained the positive response of the training, whereas most of the redox status parameters, for all training groups, restored near to the pre-exercise values at the end of the DT period. These results indicate that exercise training has a significant effect on redox status of CAD. Three months of detraining is enough to abolish the exercise-induced beneficial effects on redox status, indicating that for a better antioxidant status, exercise must be a lifetime commitment.

Experimental verification of regression to the mean in redox biology: differential responses to exercise.

An important methodological threat when selecting individuals based on initial values for a given trait is the "regression to the mean" artifact. This artifact appears when a group with an extreme mean value during a first measurement tends to obtain a less extreme value (i.e. tends toward the mean) on a subsequent measurement. The main aim was to experimentally confirm the presence of this artifact in the responses of the reference oxidative stress biomarker (F2-isoprostanes) after exercise. Urine samples were collected before and immediately following acute exercise in order to determine the level of exercise-induced oxidative stress. Afterwards, participants were arranged into three groups based on their levels of exercise-induced oxidative stress (low, moderate and high oxidative stress groups; n = 12 per group). In order to verify the existence of the regression to the mean artifact, the three groups were subjected to a second exercise trial one week after the first trial. This study confirmed the regression to the mean artifact in a redox biology context and showed that this artifact can be minimized by performing a duplicate pretreatment measurement after completing a nonrandom sorting based on the first assessment. This study also indicated that different individuals experience high oxidative stress or reductive stress (or no stress) to the same exercise stimulus even after adjusting for regression to the mean. This finding substantiates the methodological choice to divide individuals based on their degree of exercise-induced oxidative stress in future experiments to investigate the role of reactive species in exercise adaptations.

Stair descending exercise using a novel automatic escalator: effects on muscle performance and health-related parameters.

A novel automatic escalator was designed, constructed and used in the present investigation. The aim of the present investigation was to compare the effect of two repeated sessions of stair descending versus stair ascending exercise on muscle performance and health-related parameters in young healthy men. Twenty males participated and were randomly divided into two equal-sized groups: a stair descending group (muscle-damaging group) and a stair ascending group (non-muscle-damaging group). Each group performed two sessions of stair descending or stair ascending exercise on the automatic escalator while a three week period was elapsed between the two exercise sessions. Indices of muscle function, insulin sensitivity, blood lipid profile and redox status were assessed before and immediately after, as well as at day 2 and day 4 after both exercise sessions. It was found that the first bout of stair descending exercise caused muscle damage, induced insulin resistance and oxidative stress as well as affected positively blood lipid profile. However, after the second bout of stair descending exercise the alterations in all parameters were diminished or abolished. On the other hand, the stair ascending exercise induced only minor effects on muscle function and health-related parameters after both exercise bouts. The results of the present investigation indicate that stair descending exercise seems to be a promising way of exercise that can provoke positive effects on blood lipid profile and antioxidant status.

Stair descending exercise increases muscle strength in elderly males with chronic heart failure.

BACKGROUND: Previous studies from our group have shown that "pure" eccentric exercise performed on an isokinetic dynamometer can induce health-promoting effects that may improve quality of life. In order to investigate whether the benefits of "pure" eccentric exercise can be transferred to daily activities, a new and friendlier way to perform eccentric exercise had to be invented. To this end, we have proceeded to the design and construction of an automatic escalator, offering both stair descending (eccentric-biased) and stair ascending (concentric-biased) exercise. FINDINGS: Twelve elderly males (60-70 yr) with chronic heart failure participated in the present study. Participants carried out six weeks of stair descending or ascending training on the novel SmartEscalator device. Muscle damage and performance indices were evaluated before and at day 2 post exercise at the first and sixth week of training. Both training regimes increased, albeit not significantly in some cases, eccentric, concentric and isometric torque. After six weeks of stair descending exercise, eccentric, concentric and isometric peak torque increased 12.3%, 7.7% and 8.8%, respectively, whereas after stair ascending exercise eccentric, concentric and isometric peak torque increased 7.1%, 9.6% and 5.9%, respectively. CONCLUSIONS: Stair descending exercise appears to be a pleasant and mild activity that can be easily followed by the elderly. Compared to the more demanding stair ascending exercise, changes in muscle strength are similar or even greater. Elderly or people with impaired endurance wishing to increase their muscle strength may be benefited by participating in activities with strong eccentric component, such as stair descending.

Aging is not a barrier to muscle and redox adaptations: applying the repeated eccentric exercise model.

Despite the progress of analytic techniques and the refinement of study designs, striking disagreement exists among studies regarding the influence of exercise on muscle function and redox homeostasis in the elderly. The repeated eccentric exercise model was applied to produce long-lasting and extensive changes in redox biomarkers and to reveal more effectively the potential effects of aging on redox homeostasis. Ten young (20.6±0.5 years) and ten elderly men (64.6±1.1 years) underwent an isokinetic eccentric exercise session, which was repeated after three weeks. Muscle function/damage indices (torque, range of movement, muscle soreness and creatine kinase) and redox biomarkers (F2-isoprostanes, protein carbonyls, glutathione, catalase, superoxide dismutase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, uric acid, bilirubin and albumin) were assessed in plasma, erythrocytes or urine pre-exercise, immediately post-exercise and at 2 and 4 days post-exercise. As expected, the elderly group exhibited oxidative stress in baseline compared to the young group. Extensive muscle damage and extensive alterations in redox homeostasis appeared after the first bout of eccentric exercise. Noteworthy, the redox responses were similar between the age groups despite their differences in baseline values. Likewise, both age groups demonstrated blunted alterations in muscle damage and redox homeostasis after the second bout of eccentric exercise indicating adaptations from the first bout of exercise. Elderly individuals seem to be well fitted to participate in demanding physical activities without suffering detrimental effects on skeletal muscle and/or disturbances on redox homeostasis. The repeated eccentric exercise model may be a useful and practical physiological tool to study redox biology in humans.

No effect of antioxidant supplementation on muscle performance and blood redox status adaptations to eccentric training.

BACKGROUND: It was recently reported that antioxidant supplementation decreases training efficiency and prevents cellular adaptations to chronic exercise. OBJECTIVE: This study aimed to investigate the effects of vitamin C and vitamin E supplementation on muscle performance, blood and muscle redox status biomarkers, and hemolysis in trained and untrained men after acute and chronic exercise. A specific type of exercise was applied (eccentric) to produce long-lasting and extensive changes in redox status biomarkers and to examine more easily the potential effects of antioxidant supplementation. DESIGN: In a double-blinded fashion, men received either a daily oral supplement of vitamin C and vitamin E (n = 14) or placebo (n = 14) for 11 wk (started 4 wk before the pretraining exercise testing and continued until the posttraining exercise testing). After baseline testing, the subjects performed an eccentric exercise session 2 times/wk for 4 wk. Before and after the chronic eccentric exercise, the subjects underwent one session of acute eccentric exercise, physiologic measurements were performed, and blood samples and muscle biopsy samples (from 4 men) were collected. RESULTS: The results failed to support any effect of antioxidant supplementation. Eccentric exercise similarly modified muscle damage and performance, blood redox status biomarkers, and hemolysis in both the supplemented and nonsupplemented groups. This occurred despite the fact that eccentric exercise induced marked changes in muscle damage and performance and in redox status after exercise. CONCLUSION: The complete lack of any effect on the physiologic and biochemical outcome measures used raises questions about the validity of using oral antioxidant supplementation as a redox modulator of muscle and redox status in healthy humans.

A weekly bout of eccentric exercise is sufficient to induce health-promoting effects.

PURPOSE: The effects of chronic eccentric-only versus concentric-only exercise on muscle physiology and blood biochemistry were investigated. METHODS: Twenty women performed on an isokinetic dynamometer a concentric (n = 10;mean ± SEM: age = 21.0 ± 0.4 yr, body fat = 22.0% ± 0.9%) or an eccentric (n = 10, age = 20.0 ± 0.3 yr, body fat = 23.2% ± 0.7%) exercise session using the knee extensors of both lower limbs once a week for eight subsequent weeks. Muscle function (isometric, concentric, and eccentric peak torque, range of movement, and soreness) was evaluated before, immediately after, and 48 h postexercise in each one of the eight training weeks. Body fat, resting energy expenditure (REE), lipid, and carbohydrate oxidation rate as well as blood chemistry measurements (lipid, lipoprotein and apolipoprotein profile, glucose, insulin, glycosylated hemoglobin, and creatine kinase) were examined before and 48 h postexercise at the first and eighth week of training. RESULTS: Acute eccentric exercise increased REE and fat oxidation at week 1 (12.7% and 12.9%, respectively) and at week 8 (0.7% and 2.8%, respectively). Chronic eccentric exercise increased resting REE and fat oxidation at week 8 compared with week 1 (5.0% and 9.9%, respectively). Acute eccentric exercise improved blood lipid profile at week 1 and week 8. Chronic eccentric exercise improved resting blood lipid profile at week 8. Acute eccentric exercise increased insulin resistance at week 1 but not at week 8. Chronic eccentric exercise decreased resting insulin resistance at week 8. CONCLUSION: It is reported for the first time that only 30 min of eccentric exercise per week for 8 wk was sufficient to improve health risk factors.