Low-Volume Sprint Interval Swimming Is Sufficient to Increase Blood Metabolic Biomarkers in Master Swimmers.

Purpose: Sprint interval exercise is a time-efficient way of inducing beneficial adaptations. However, little is known about its minimal effective volume, especially in swimming. The aim of the present study was to evaluate and compare the effects of two sprint interval swimming sets of different low volumes on blood biomarkers. Method: Twenty-one master swimmers [11 females aged 38.5 (8.5) years, 10 males aged 42.7 (5.7) years] completed two freestyle swimming sets of 4 × 50 m and 4 × 25 m at maximal intensity and a work-to-rest ratio of 1:1, on different days, in random and counterbalanced order. Blood samples were taken before, immediately after and one hour after exercise for determination of a number of biochemical parameters. Results: Swimming speed was higher in the 4 × 25-m set. Lactate, glucose, insulin, glucagon, cortisol, and reduced glutathione increased immediately post-exercise, while uric acid increased 1 h post-exercise (p < .05). All aforementioned biomarkers, excluding glucagon, increased more with the 4 × 50-m set, compared to the 4 × 25-m set (p < .05). Session rating of perceived exertion was higher after the 4 × 50-m set (p = .011). Conclusion: Both sprint interval swimming sets elicited increases in blood biomarkers in master swimmers. The set of higher volume elicited greater increases in most of the biochemical markers studied but also in subjective load. Thus, although the set of higher volume was more efficient in perturbing blood biomarkers, even the very low-volume set induced metabolic stress that may trigger adaptive mechanisms.

Efficacy of Nx4 to Reduce Plasma Cortisol and Gastrin Levels in Norwegian Sled Dogs During an Exercise Induced Stress Response: A Prospective, Randomized, Double Blinded, Placebo-Controlled Cohort Study.

Introduction: An exercise induced stress response is commonly seen in high performance sled dogs, resulting in increased plasma cortisol. A stress induced rise of cortisol might result in increased prevalence of gastritis and gastric ulcers mediated by an increase of gastrin. Neurexan® (Nx4) is a medicinal product used for stress relief by reduction of cortisol. The aim of the study was to show that Nx4 reduces plasma cortisol and plasma gastrin in high performance sled dogs and to show tolerability of Nx4 in dogs. Material and Methods: First, a pilot study was done to validate the increase of cortisol by performance. The data from the pilot study was used for sample size estimation via an adapted power analysis as well as the identification of important variables. These were then used in the randomization procedure of the main study. Second, a prospective randomized, double blinded, placebo-controlled cohort study was conducted. The main study included 45 sled dogs, assigning 23 dogs to the Nx4 group, and 22 dogs to the placebo group, to analyze plasma cortisol and plasma gastrin at four time points: before, directly after and 30 and 120 min after performance. Results: For the main target variable, area under the curve (AUC) of plasma cortisol, a significantly lower adjusted mean value in the Nx4 group compared to the placebo group (p = 0.031) was found. Plasma gastrin was also significantly reduced in the Nx4 group 30 min after performance (p = 0.023), resulting in a significantly reduced plasma gastrin AUC in the Nx4 group compared to the placebo group (p = 0.049). Discussion: Within the limitation of the study, the results carry implications for the usefulness of Nx4 to reduce exercise induced plasma cortisol and gastrin levels. The reduction of the exercise induced stress response could help to improve the welfare of high-performance sled dogs. Since activation of the hypothalamic-pituitary-adrenal axis resulting in increased cortisol is similar for exercise induced stress and psychologic stress, the same might be true independent of the stressor, making Nx4 potentially useful in any stressful situation for dogs.

Towards ageing well: Use it or lose it: Exercise, epigenetics and cognition.

More and more people are living into the 90s or becoming centenarians. But, the gift of increased 'age span' seldom equates with an improved 'health-span'. Governments across the world are expressing concern about the epidemic of chronic disease, and have responded by initiating policies that make prevention, reduction and treatment of chronic disease, a public health priority. But understanding, how to age long and well, with the avoidance of chronic disease and later life complex disease morbidity is challenging. While inherited genes have an undoubted role to play in the chance of maintaining good health or conversely a predilection to developing disease and chronic ill health, there is increasing evidence that behavioural and environmental life-style choices may contribute up to 50% of the variability of human lifespan. Physical exercise is readily available to everyone, and is a simple cheap and effective form of life-style intervention. Exercise appears to help maintain good health and to reduce the risk of developing chronic disease and ill health. Evidence suggests that physical activity improves well-being across many health domains through out life, continues to offer important health benefits in older age groups and tracks with a 'healthy ageing' profile. Although many of the molecular pathways remain to be fully identified, here we discuss how physical activity and exercise is understood to produce changes in the human epigenome, which have the potential to enhance cognitive and psychological health, improve muscular fitness, and lead to better ageing with improved quality of life in older age.

Rosa rugosa Aqueous Extract Alleviates Endurance Exercise-Induced Stress.

This study was performed to investigate the effect of water extract from Rosa rugosa (RRW) on endurance exercise-induced stress in mice. The mice were orally administered with distilled water or RRW, respectively. The endurance capacity was evaluated by exhaustive swimming using an adjustable-current water pool. Mice administered RRW swam longer before becoming exhausted. Also, RRW administration resulted in less lipid peroxidation, lower muscular antioxidant enzyme activities, and lower cortisol level. The results suggest that RRW can prevent exercise-induced stress by decreasing oxidative stress levels.

STUDIES ON EXERCISE-INDUCED STRESS IN GROWING STATE / 体力科学

This study was performed to investigate the exercise-induced stress in growing state in order to prevent the death during or after exercise. Thirty eight male and female subjects in junior high school were administered 5 minutes running test for 3 succesive years. Heart rate, blood pressure, electrocardiogram, and blood biochemical components were measured before and after 5 minutes running test. Prior to 5 minutes running test the investigation of the number of food intake and total steps a day were performed. The results obtained were as follows;<BR>1) After 5 minutes running test, the subjects who had larger increment in CK-MB/ CK ratio walked fewer steps a day and had fewer number of food intake. And they had more drinks, especially juices.<BR>2) In female subjects an excess of body fat was not a risk factor, but not in male subjects.<BR>3) The subjects, who had larger increment in body fat than in body weight, tended to become higher levels in blood pressure and heart rate in resting than others.<BR>4) The subjects, who walked more longer in 2 nd grade than 1 st grade in junior high school, tended to decrease the increment of heart rate before to immediately after 5 minutes running test.<BR>5) Blood biochemical components were normal even if electrocardiogram was abnormal.<BR>6) At 24 hours after 5 minutes running test, CK-MB/CK ratio and serum lipoperoxide levels increased and serum protein and albumin levels defreased in 3 rd grade in junior high school.<BR>Consequently in order to prevent the death during or after exercise the investigation of food intake, total steps a day, and body fat must be administered before exercise sufficiently. And then electrocardiogram and blood biochemical components, especially CK-MB activity must be checked before, during, and after exercise testing.