Time-of-Day Effects on Anaerobic Power and Concentration of Selected Hormones in Blind Men.

Knowledge of the circadian rhythm of the blind person and diurnal changes in anaerobic power and hormones concentration can create the possibility of individualising physical training. The aim of the study was to examine the time-of-day effects on anaerobic performance and the concentration of selected hormones. The measurements were performed at two different times of the day (10:00 a.m., 10:00 p.m.) in blind men at the age of 20-25 years old. The experiment group was chosen by using repeated hormonal tests four times a day so that each selected patient had a sleep/wake cycle even of 24 h. Anaerobic peak power and total work were tested in an anaerobic sprint test, and the concentration of growth hormone, testosterone, cortisol, and melatonin was determined. In blind men, the hormonal response was not driven by the photoperiod as in the control group. In the blind group, at 10:00 p.m., anaerobic peak power and total work results were significantly higher than at 10:00 a.m. and negatively correlated with melatonin levels. No such correlation was found in the control group.

Physiological response and cardiorespiratory adaptation after a 6-week Nordic Walking training targeted at lipid oxidation in a group of post-menopausal women.

This study examined the effects of a 6-week Nordic Walking (NW) training, at the intensity corresponding to the dominance of lipid metabolism, on the levels of selected physiological indices, the haemodynamic indices of the cardiovascular system and physical fitness in sedentary women older than 55 years of age. In addition, the physiological response of the female body to the walking effort on treadmill with poles (NW) and without poles (W) was compared and the influence of training on this response was determined. A single group study with a pre-test/post-test study design was conducted. Eighteen women performed NW controlled intensity training 3 times a week for 6 weeks. Body composition, resting blood pressure (BP), heart rate (HR), maximum oxygen uptake (VO2max) as well as circulatory and respiratory indices in two graded walking efforts on mechanical treadmill NW and W were measured before and after training period. The intensity of workouts, which considered the dominance of lipid metabolism, was determined individually, based on the dynamics of changes in the level of physiological indices during the graded intensity NW. After the course of training, body mass, fat mass, resting BP and HR decreased significantly (p < 0.05). HR and respiratory exchange ratio recorded during NW and W at 1.75 m.s-1 walking speed decreased, while the oxygen pulse increased (p < 0.05). VO2max increased significantly (p < 0.05). Before and after the training period HR, oxygen uptake per minute, and energy expenditure during NW were significantly higher than in W (p < 0.05). The study showed that 6-week NW training at the intensity corresponding to the dominance of lipid metabolism can provide improvement in body composition, cardiovascular function and physical performance in previously sedentary women. NW compared to the regular walk with the same speed revealed higher energy expenditure.

Effects of 6-week Nordic walking training on body composition and antioxidant status for women > 55 years of age.

OBJECTIVES: This study examined the effects of 6-week Nordic walking (NW) workout with individually customized intensity, on the body composition, and oxidative stress biomarkers for women > 55 years of age. MATERIAL AND METHODS: Sixteen sedentary women (age 58.1±2.02 years old, body mass index (BMI) 26.74±2.72 kg/m2) worked out the NW 3 times/week over the 6-week period. Training intensity, which reflected the dominance of oxygen metabolism, was determined based on changes in physiological indicators during graded exercise on a treadmill (walking with poles). The body composition and oxidative stress biomarkers in blood were measured before and after the exercise routine. RESULTS: After the training period, body weight, body fat percentage, body mass index and uric acid levels in serum decreased significantly (p < 0.05). At the same time the plasma total antioxidant status increased considerably (p < 0.05), while the total oxidative status and the oxidized low-density lipoproteins concentration levels did not change significantly (p > 0.05). CONCLUSIONS: Within a relatively short time, the Nordic walking with the customized intensity level focused on the dominance of fat metabolism, decreased body fat and improved the blood antioxidant defense system for previously sedentary women. Int J Occup Med Environ Health 2017;30(3):445-454.

Effects of a 6-week Nordic walking training on changes in 25(OH)D blood concentration in women aged over 55.

BACKGROUND: Nordic walking is a form of physical activity recommended for people of all ages and it is used in disease prevention and health promotion. The study was aimed to determine if and in what ways a six-week Nordic walking training program in late autumn may affect 25(OH)D concentration in postmenopausal overweight women. METHODS: Two series of measurements were carried out in a group of 17 women aged 57±4.20 years with low physical activity level. The first series encompassed a 6-week Nordic walking training program at the intensity of 60-70% VO2max. Before and after the training program body composition was determined with a densitometer, and biochemical indices were measured in blood samples drawn at rest. After a year a second series of measurements at rest was carried out to determine whether changes in the vitamin D (25(OH)D) blood level were season-induced or modified by physical activity. RESULTS: The Nordic walking training program contributed to a significant reduction of body mass, percentage fat volume and BMI in the examined women. The mean 25(OH)D concentration in the examined women significantly decreased after 6 weeks of training. No similar vitamin D level changes were observed in the II measurement series. CONCLUSIONS: A six-week Nordic walking training program in late autumn contributed to the lowering of 25(OH)D blood concentration in women after 55 years of age. The decreased 25(OH)D concentration may have been a result of reduced dermal biosynthesis of vitamin D or due to vitamin D contribution to muscle metabolism. This is an indication that vitamin D3 supplementation should be recommended in periods of intense physical activity during months with little insolation, especially to overweight postmenopausal women.