Seasonal acclimation in sudomotor function evaluated by QSART in healthy humans

The quantitative sudomotor axon reflex testing (QSART) is a classic test of routine postganglionic sudomotor function. We investigated sudomotor function by QSART after summer (July 2012) and winter (January 2013) seasonal acclimation (SA) in the Republic of Korea. QSART with acetylcholine (ACh) iontophoresis were performed to determine directly activated (DIR) and axon reflex-mediated (AXR1, 2) sweating rate. Onset time of axon reflex, activated sweat gland density (ASGD), activated sweat gland output (ASGO), tympanic and skin temperatures (T(ty), T(sk)), basal metabolic rate (BMR), and evaporative loss volume changes were measured. Tympanic and mean body temperature (T(b); calculated from T(ty), T(sk)) were significantly lower after summer-SA than that of winter-SA. Sweat onset time was delayed during winter-SA compared to that after summer-SA. BMR, AXR(1), AXR(2), and DIR sweat rates, ASGD and ASGO, and evaporative loss volume were significantly diminished after winter-SA relative to after summer-SA. In conclusion, changes in sweating activity measured by QSART confirmed the involvement of the peripheral nervous system in variation of sudomotor activity in seasonal acclimation.

Effect of Ultra-marathon (308 km) Race on Bone Metabolism and Cartilage Damage Biomarkers

OBJECTIVE: To evaluate the potential effects of a 308-km ultra-marathon on bone and cartilage biomarkers. METHOD: Venous blood samples were collected at pre-race, 100 km, 200 km, and 308 km checkpoints. The following markers of cartilage damage and bone metabolism were studied: osteocalcin (OC), osteoprotegerin (OPG), and calcium, phosphorous, and cartilage oligomeric matrix protein (COMP). RESULTS: Blood samples were taken from 20 male runners at four different checkpoints. Serum COMP was increased by 194.1% (130.7% at 100 km and 160.4% at 200 km). Serum OPG was significantly increased by 158.57% at 100 km and 114.1% at 200 km compared to the pre-race measures. OC was transiently suppressed at 200 km. Serum calcium and phosphorous concentrations decreased compared to the pre-race measures. CONCLUSION: This study showed that the 308-km ultra-marathon induced several changes, including transient uncoupling of bone metabolism, increased bone resorption, suppressed bone formation, and bone turnover and had a major impact on cartilage structure.

The Effect of Supplementary Selenium on Leukocytes and HSP70 Expression after Half-Body Immersion

This study examined the effect of supplementary selenium on leukocytes and heat shock protein (HSP) 70 expression in serum during half-body immersion. The subjects were male college tennis athletes. All subjects participated in two repeated experiments with a 1 week interval. During the 30 min intermittent half-body immersion, subjects were given 500 mL of water with or without selenium (100 microg). Blood samples were taken from the antecubital vein, and differential counts were made. Serum HSP70 protein was analyzed using a commercial ELISA kit. After half-body immersion, leukocytes and lymphocytes increased significantly but neutrophils decreased significantly in both trials (with or without selenium). Selenium supplementation, compared with placebo, decreased levels of leukocytes, neutrophils, and monocytes, but not lymphocytes, to the resting level or below 60 min after immersion. Only lymphocytes continued to increase in both trials during the recovery period. Serum HSP70 protein level did not change after immersion, but it decreased 60 min after immersion with the administration of selenium. In conclusion, supplementary selenium reduced the systemic immune response and serum HSP70 protein accumulation after half-body immersion.

Erratum: Effect of Posture on Muscle Activity and Oxygen Uptake in Cycle Ergometer / 대한스포츠의학회지

No abstract available.

Effect of Posture on Muscle Activity and Oxygen Uptake in Cycle Ergometer / 대한스포츠의학회지

This study evaluated the effects of saddle height on the muscle activity and oxygen uptake during bicycling. The subjects were 20 young adult volunteers. Muscle activity and oxygen uptake were measured with the two saddle heights (maximum knee extension of 180degrees and 120degrees) and at two power outputs (70 and 100 watts, respectively.) The pedaling rate was 40 rpm. The exercise time was 1 minute and the resting time between each condition was 3 minutes. The raw electromyogram activity was measured for 1 minute and was converted to a root mean square value. Oxygen uptake was measured during exercise using the mixing chamber mode. The activities of two flexors (the medial hamstring and medial head of gastrocnemius) increased at the high saddle height and the activities of four extensors (rectus femoris, vastus medialis, vastus lateralis, and tibialis anterior) increased at the low saddle height. The oxygen uptake at the low saddle height was significantly higher than that at the high saddle height. The oxygen uptake positively correlated with the muscle activities of the knee extensors. The muscle activity and oxygen uptake were significantly affected by the postures (saddle heights) in cycle ergometer. The postures should be considered in the exercise test and prescription.

The effect of Oligonol intake on cortisol and related cytokines in healthy young men

This study investigated the effects of Oligonol intake on cortisol, interleukin (IL)-1beta, and IL-6 concentrations in the serum at rest and after physical exercise loading. Nineteen healthy sedentary male volunteers participated in this study. The physical characteristics of the subjects were: a mean height of 174.2 +/- 2.7 cm, a mean weight of 74.8 +/- 3.6 kg and a mean age of 22.8 +/- 1.3 years. Each subject received 0.5 L water with Oligonol (100 mg/day) (n = 10) or a placebo (n = 9) daily for four weeks. The body composition, the white blood cell (WBC) and differential counts as well as the serum cortisol, IL-1beta, and IL-6 concentrations were measured before and after Oligonol intake. The cortisol concentration and serum levels of IL-1beta and IL-6 after Oligonol intake were significantly decreased compared to before treatment (P < 0.01, respectively). In addition, the rate of increase of these factors after exercise was decreased compared to the placebo group. There was no change in the WBC and differential cell counts. These results suggest that oral Oligonol intake for four weeks had a significant effect on inhibition of inflammatory markers in healthy young men.

Effect of the Heat-exposure on Peripheral Sudomotor Activity Including the Density of Active Sweat Glands and Single Sweat Gland Output

Tropical inhabitants are able to tolerate heat through permanent residence in hot and often humid tropical climates. The goal of this study was to clarify the peripheral mechanisms involved in thermal sweating pre and post exposure (heat-acclimatization over 10 days) by studying the sweating responses to acetylcholine (ACh), a primary neurotransmitter of sudomotor activity, in healthy subjects (n=12). Ten percent ACh was administered on the inner forearm skin for iontophoresis. Quantitative sudomotor axon reflex testing, after iontophoresis (2 mA for 5 min) with ACH, was performed to determine directly activated (DIR) and axon reflex-mediated (AXR) sweating during ACh iontophoresis. The sweat rate, activated sweat gland density, sweat gland output per single gland activated, as well as oral and skin temperature changes were measured. The post exposure activity had a short onset time (p<0.01), higher active sweat rate [(AXR (p<0.001) and DIR (p<0.001)], higher sweat output per gland (p<0.001) and higher transepidermal water loss (p<0.001) compared to the pre-exposure measurements. The activated sweat rate in the sudomotor activity increased the output for post-exposure compared to the pre-exposure measurements. The results suggested that post-exposure activity showed a higher active sweat gland output due to the combination of a higher AXR (DIR) sweat rate and a shorter onset time. Therefore, higher sudomotor responses to ACh receptors indicate accelerated sympathetic nerve responsiveness to ACh sensitivity by exposure to environmental conditions.

Long-Term Tropical Residency Diminishes Central Sudomotor Sensitivities in Male Subjects

Tropical natives (TROP) are capable of tolerating tropical heat because of their long-term adaptation to tropical environments. When exposed to heat stress, these natives tend to respond with lower sweat output, which is generally thought to be the result of heat acclimatization. The main objective of this study was to clarify central mechanisms inherent to suppressed thermal sweating in tropical natives (Malaysians) by comparing their sweating responses to those of temperate native (TEMP) (Koreans). This experiment was conducted in a thermoneutral climatic chamber (24+/-0.5 degrees C, 40+/-3% relative humidity). Heat loads were applied to each subject by the immersion of their lower legs in a hot water bath (43 degrees C for 30 min). Sweat onset-time and sweat volume were compared between TROP and TEMP. The sweat onset-times on four selected points on the body ranged from 10.25 to 13.47 min in TEMP subjects, and from 16.24 to 17.83 min in TROP subjects (p<0.001). The local sweat volumes at the same sites ranged from 4.30 to 9.74 mg/cm2 in TEMP subjects, and from between 1.80 to 4.40 mg/cm2 in TROP subjects (p<0.001). These results demonstrated a significant difference between TROP and TEMP subjects with regard to the manner in which they regulate their body temperatures when exposed to heat loads, and verified that long-term thermal adaptation blunts sweating sensitivities.

Comparison of Interleukin-8 Levels in Long-Distance Runners and Healthy Sedentary Non-Athletic Control Subjects

We have previously demonstrated that the level of leukocytes and neutrophils significantly increased immediately and 30 min after exercise. Interleukin-8 (IL-8) is an inflammatory cytokine that acts as a chemokine on neutrophils. In the present study, we evaluated the correlation between the number of neutrophils and leukocytes, and between the number of neutrophils and plasma IL-8 level. Long-distance trained runners (TRs, n = 10) and untrained sedentary control subjects (SEDs, n = 10) ran for one hour at 70% of heart rate reserve. In the TR, the number of neutrophils correlated significantly with the number of leukocytes in the blood. However, there was no correlation between the number of neutrophils and the plasma IL-8 concentration in both groups. Expressions of IL-8 protein and mRNA were markedly higher in the TRs as compared to the SEDs at three time intervals (pre-exercise, immediately after exercise, and post exercise). In conclusion, our results show that 1) the neutrophil level was dependent on the level of leukocytes 2) there was no correlation between the neutrophils count and plasma IL-8 concentration and 3) a higher plasma IL-8 level in athletes may be a unique characteristic of intensive training.

Sweating by Exercise Controls Body Temperature through Increase of Interleukin-1beta

This study was designed to investigate the expression and production of interleukin-1beta (IL-1beta) in human peripheral blood of trained runners and untrained controls after temporary moderate intensity exercise. Male long-distance trained runners (TR) and untrained sedentary control subjects (SED) ran for 1 h at 70% of heart rate reserve (HRR). IL-1beta gene and protein expressions were significantly higher in TR than those with SED at all 3 intervals examined independently. Significant increases in total sweat volume and oral temperature were observed after exercise in both groups, however, there were some differences between the groups. We conclude, therefore, that sweating due to exercise is associated with increase of IL-1beta and it is correlated with decrease of oral temperature.

Effect of Rhodiola Sachalinensis Administration and Endurance Exercise on Insulin Sensitivity and Expression of Proteins Related with Glucose Transport in Skeletal Muscle of Obese Zucker Rat

Peripheral insulin resistance in obese/type II diabetes animals results from an impairment of insulin-stimulated glucose uptake into skeletal muscle. Insulin stimulate the translocation of GLUT4 from intracellular location to the plasma membrane. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) is implicated in mediation of fusion of GLUT4-containing vesicle with the plasma membrane. Present study investigated regulatory effects of Rhodiola sachalinensis administration and exercise training on the expression of GLUT4 protein and SNAREs protein in skeletal muscles of obese Zucker rats. Experimental animals were randomly assigned into one of five groups ; lean control (LN), obese control (OB), exercise-treated (EXE), Rhodiola sachalinensis-treated (Rho), combine of Rho & EXE (Rho-EXE). All animals of exercise training (EXE, Rho-EXE) performed treadmill running for 8 weeks, and animals of Rho groups (Rho, Rho-EXE) were dosed daily by gastric gavage during the same period. After experiment, blood were taken for analyses of glucose, insulin, and lipids levels. Mitochondrial oxidative enzyme (citrate synthase, CS ; beta-hydroxyacyl-CoA dehydrogenase, beta-HAD) activity were analysed. Skeletal muscles were dissected out for analyses of proteins (GLUT4, VAMP2, syntaxin4, SNAP23). Results are as follows. Exercise and/or Rhodiola sachalinensis administration significantly reduced body weight and improved blood lipids (TG, FFA), and increased insulin sensitivity. Endurance exercise significantly increased the activity of mitochondrial enzymes and the expression of GLUT4 protein, however, administration of Rhodiola sachalinensis did not affect them. The effect of exercise and/or Rhodiola sachalinensis administration on the expression of SNARE proteins was unclear. Our study suggested that improvement insulin sensitivity by exercise and/or Rhodiola sachalinensis administration in obese Zucker rats is independent of expression of SNARE proteins.

Effect of Korean red ginseng on the levels of serum p24 antigen, ?-microglobulin, and CD4+T cell counts in HIV infected patients treated with AZT(I)

No abstract available.