A study of physical demands in riding

Thirteen experienced riders and three elite riders underwent bicycle ergometer tests at submaximal and maximal workloads. Oxygen uptake, pulmonary ventilation and heart rate were also studied during riding at a walk, a trot and a canter. The mean maximal oxygen uptake of the experienced riders in the ergometer test (2.71 . min-1) was superior to the average maximal oxygen uptake of other groups of the same age and sex. The average oxygen uptake of the experienced riders in trot sitting was 1.701 . min-1, trot rising 1.681 . min-1 and in canter 1.801 . min-1. The experienced riders used at least 60% of their maximal aerobic power in trot and canter, which is an exercise intensity that may induce some training effect. Two elite riders consistently had lower oxygen uptakes in riding than the other riders. The heart rate -- oxygen uptake relationships in riding and in the ergometer tests were similar, except during trot sitting when the heart rate tended to be higher, indicating a larger share of static muscle contraction in this gait. Static muscle strength was measured in nine riders and seven non-riders. Six muscle groups were investigated, but no significant difference in muscle strength could be demonstrated between riders and controls.     

Peroxidase catalysed aerobic degradation of 5,6,7,8-tetrahydrobiopterin at physiological pH

The aerobic degradation of 5,6,7,8-tetrahydrobiopterin at neutral pH is catalysed by peroxidase (EC 1.11.1.7) and provides quinonoid 7,8-dihydro(6H)biopterin which readily loses the side chain to yield 7,8-dihydro(3H)pterin. The latter is in equilibrium with trace amounts of 6-hydroxy-5,6,7,8-tetrahydropterin (covalent hydrate) which is irreversibly oxidised to quinonoid 6-hydroxy-7,8-dihydro(6H)pterin, and this finally rearranges to 7,8-dihydroxanthopterin. Spectroscopic evidence (ultraviolet, 1H NMR and 13C NMR) is presented for the reversible addition of water across the 5,6-double bond of 7,8-dihydro(3H)pterin. The intermediate quinonoid 6-hydroxy-7,8-dihydro(6H)pterin is a good substrate for dihydropteridine reductase (EC 1.6.99.7) with a Km of 16.3 microM and kcat of 22.5 s-1. The rate of aerobic degradation (oxidation and loss of the side chain) of natural (6R)-5,6,7,8-tetrahydrobiopterin is several times slower than the rate for the unnatural (6S) isomer. By using a modified assay procedure the kinetic parameters for dihydropteridine reductase are as follows: with (6R)-7,8-dihydro(6H)biopterin Km = 1.3 microM and kcat = 22.8 s-1; with (6S)-7,8-dihydro(6H)biopterin Km = 13.5 microM and kcat = 51.6 s-1; and with (6RS)-7,8-dihydro(6H)neopterin Km = 19.2 microM and kcat = 116 s-1.     

Fit women are not able to use the whole aerobic capacity during aerobic dance

Edvardsen, E, Ingjer, F, and B?, K. Fit women are not able to use the whole aerobic capacity during aerobic dance. J Strength Cond Res 25(12): 3479-3485, 2011-This study compared the aerobic capacity during maximal aerobic dance and treadmill running in fit women. Thirteen well-trained female aerobic dance instructors aged 30 ± 8.17 years (mean ± SD) exercised to exhaustion by running on a treadmill for measurement of maximal oxygen uptake (VO(2)max) and peak heart rate (HRpeak). Additionally, all subjects performed aerobic dancing until exhaustion after a choreographed videotaped routine trying to reach the same HRpeak as during maximal running. The p value for statistical significance between running and aerobic dance was set to ≤0.05. The results (mean ± SD) showed a lower VO(2)max in aerobic dance (52.2 ± 4.02 ml·kg·min) compared with treadmill running (55.9 ± 5.03 ml·kg·min) (p = 0.0003). Further, the mean ± SD HRpeak was 182 ± 9.15 b·min in aerobic dance and 192 ± 9.62 b·min in treadmill running, giving no difference in oxygen pulse between the 2 exercise forms (p = 0.32). There was no difference in peak ventilation (aerobic dance: 108 ± 10.81 L·min vs. running: 113 ± 11.49 L·min). In conclusion, aerobic dance does not seem to be able to use the whole aerobic capacity as in running. For well endurance-trained women, this may result in a lower total workload at maximal intensities. Aerobic dance may therefore not be as suitable as running during maximal intensities in well-trained females.     

晋城地区女性阴道需氧菌感染情况调查分析

目的 调查晋城地区需氧菌阴道炎(AV)的发病情况.方法 采用需氧菌阴道炎/细菌性阴道病联合测定技术对阴道分泌物进行快速检测.结果 1936例受检者中,AV患者242人,总体发病率为12.50％(242/1936).其中单纯AV感染93例,占38.43％,AV合并其他感染患者149人,占61.57％.70 ～81岁年龄组的AV发病率最高,达到了20.53％(8/39).其次为50 ～59岁年龄组和30～ 39岁年龄组,AV发病率分别为16.73％(46/275)和15.29％(98/641).40 ～49岁年龄组,AV的发病率最低,为6.63％(39/588).结论 AV易合并其他感染,应引起临床足够的重视.     

Periurethral aerobic microflora of pregnant and non-pregnant women.

Seventy-two pregnant and 88 non-pregnant women were examined to see whether the periurethral region had been colonised with group B streptococci (Streptococcus agalactiae), enterococci, and Gram-negative rods belonging to the Enterobacteriaeceae. A semi-quantitative method was used for periurethral sampling, and paired urethral swabs were also collected to compare the isolation rates of group B streptococci from the two sites and with the two sampling methods. A higher isolation rate was found with periurethral sampling. Most specimens showed no or scanty growth of Gram-negative rods. Pregnancy was often associated with heavy growth of enterococci. Sampling performed during menstruation and while oral contraceptives were being used produced high isolation rates of group B streptococci. These results seem to suggest that the periurethral area might protect against genital colonisation with group B streptococci as it does against urinary tract infection and that hormonal factors influence the carriage of these organisms.     

Plasma ADMA concentrations associate with aerobic fitness in postmenopausal women

Aims

Asymmetric dimethylarginine (ADMA) is an endogenous competitive inhibitor of nitric oxide (NO) synthase, an enzyme responsible for the generation of NO. Plasma concentrations of ADMA increase in the elderly and in postmenopausal women. In fact, an elevated ADMA level is a risk factor of cardiovascular disease. Aerobic exercise has a beneficial effect on cardiovascular disease. However, the relationship between ADMA and aerobic fitness is unknown. The aim of this study was to determine whether plasma ADMA concentrations correlate with aerobic fitness levels in postmenopausal women.

Main methods

Thirty healthy postmenopausal women aged 50–76 years participated in this study. We measured plasma concentrations of ADMA and oxygen consumption at the ventilatory threshold (VO_2VT) as an index of aerobic fitness. Subjects were divided into the low aerobic fitness (Low fitness) and high aerobic fitness (High fitness) groups, and the dividing line was set at the median VO_2VT value.

Key findings

VO_2VT was significantly higher in the High fitness group than in the Low fitness group (P < 0.01). The plasma ADMA concentrations in the High fitness group were significantly lower than those in the Low fitness group (P < 0.05). There was a negative correlation between plasma ADMA concentrations and VO_2VT (r = − 0.532, P < 0.01).

Significance

We found that plasma ADMA concentrations were associated with aerobic fitness in postmenopausal women. The results of this study suggest that habitual aerobic exercise may decrease plasma ADMA concentrations.     

A comparison of physiological responses and rating of perceived exertion between high-impact and low-impact aerobic dance sessions

The aim of this study was to compare the exercise intensity and rating of perceived exertion (RPE) of a high-impact (HIP) and a low-impact (LIP) university aerobic dance session. Ten women [mean (SD) age 22.9 (2.6) years] took part in the study. An incremental treadmill test was performed by each subject to determine maximum oxygen consumption (V˙O_{2 max} ) and maximum heart rate (HR _max ). The measured V˙O_{2 max} [mean (SD)] was 49.0 (7.5) ml · kg⁻¹ · min⁻¹. The subjects were randomly assigned to LIP and HIP sessions (i.e. five of the subjects participated in the HIP session first, and the other five participated in the LIP session first). In a laboratory, heart rate, oxygen uptake and RPE were measured throughout each session for each subject. Expired air was collected continuously throughout the sessions using Douglas bags (ten bags over a 30-min period). The sessions consisted of 20 min of aerobic exercise (bags 1–7) followed by 5 min of local muscular endurance exercise (bags 8 and 9) and 5 min of flexibility exercises (bag 10). The mean intensity of the aerobic section of the LIP and HIP sessions was 51.6% and 64.7% V˙O_{2 max} , respectively. Ninety-five percent confidence intervals for the average difference between the HIP and LIP sessions demonstrate that the %V˙O_{2 max} was between 12% and 14% higher for the HIP session. The mean %HR _max for the LIP and HIP sessions was 71.4% and 76.7%, respectively, with the %HR _max in the HIP session being between 5.4% and 7.2% higher on average than that of the LIP session. On average, the RPE for the aerobic section of the HIP session (12.1) was consistently higher than that of the LIP session (11.1). HIP activity has the potential to maintain/improve the aerobic fitness of its participants. According to the literature, the exercise intensity elicited by LIP activity may have a limited training effect for the population utilised in this study, and for some individuals may result in detraining. Conversely, LIP activities may be an appropriate mode of exercise for overweight and unfit individuals. Accepted: 5 January 1998     

Effects of aerobic exercise on serum leptin levels in obese women

It has been demonstrated that leptin concentrations in obese patients may be altered by weight loss. We examined the effects of a 9-week aerobic exercise program on serum leptin concentrations in overweight women (20-50% above ideal body mass) under conditions of weight stability. Sixteen overweight women, mean (SE) age 42.75 (1.64) years, comprised the exercise group which adhered to a supervised aerobic exercise program. A graded exercise treadmill test was conducted before and after the exercise program to determine maximal oxygen uptake (VO2max) using open-circuit spirometry. The women demonstrated improved aerobic fitness (VO2max increased 12.29%), however, body fat and the body mass index did not change significantly [42.27 (1.35)-41.87 (1.33)%]. Fourteen women, age 40.57 (2.80) years, did not exercise over the same time period and served as a control group. Serum leptin levels were not significantly altered for either the exercise [28.00 (2.13)-31.04 (2.71) ng x ml(-1)] or the control group [33.24 (3.78)-34.69 (3.14) ng x mg(-1)]. The data indicate that 9 weeks of aerobic exercise improves aerobic fitness, but does not affect leptin concentrations in overweight women.     

Longitudinal changes in aerobic power in older men and women.

The purpose of this study was to describe the longitudinal (10 yr) decline in aerobic power [maximal O(2) uptake (Vo(2 max))] and anaerobic threshold [ventilatory threshold (T(Ve))] of older adults living independently in the community. Ten years after initial testing, 62 subjects (34 men, mean age 73.5 +/- 6.4 yr; 28 women, 72.1 +/- 5.3 yr) achieved Vo(2 max) criteria during treadmill walking tests to the limit of tolerance, with T(Ve) determined in a subset of 45. Vo(2 max) in men showed a rate of decline of -0.43 ml.kg(-1).min(-1).yr(-1), and the decline in Vo(2 max) was consequent to a lowered maximal heart rate with no change in the maximum O(2) pulse. The women showed a slower rate of decline of Vo(2 max) of -0.19.ml.kg(-1).min(-1).yr(-1) (P < 0.05), again with a lowered HR(max) and unchanged O(2) pulse. In this sample, lean body mass was not changed over the 10-yr period. Changes in Vo(2 max) were not significantly related to physical activity scores. T(Ve) showed a nonsignificant decline in both men and women. Groupings of young-old (65-72 yr at follow-up) vs. old-old (73-90 yr at follow-up) were examined. In men, there were no differences in the rate of Vo(2 max) decline. The young-old women showed a significant decline in Vo(2 max), whereas old-old women, initially at a Vo(2 max) of 19.4 +/- 3.1 ml.kg(-1).min(-1), showed no loss in Vo(2 max). The longitudinal data, vs. cross-sectional analysis, showed a greater decline for men but similar estimates of the rates of change in women. Thus the 10-yr longitudinal study of the cohort of community-dwelling older adults who remained healthy, ambulatory, and independent showed a 14% decline in Vo(2 max) in men, and a smaller decline of 7% in women, with the oldest women showing little change over the 10-yr period.     

Glutamine- vs glucose-supported motor activity in Schistosoma mansoni: physiological relevance of aerobic metabolism

The ability of Schistosoma mansoni to generate energy through aerobic metabolic processes was examined in adult parasites in vitro. Parasite catabolism of radiolabeled glucose, glutamine, and other amino acids to CO2 and Krebs cycle intermediates was measured under a variety of incubation conditions. L-Glutamine was metabolized to CO2 via the intermediates glutamate, alpha-ketoglutaramate, and alpha-ketoglutarate in worms incubated in a balanced salts solution containing this amino acid as the only organic constituent. Of the other amino acids tested, CO2 production was detected from L-glutamate and L-asparagine. The catabolism of L-glutamine to CO2 was reduced by the respiratory inhibitor antimycin A. The motility of schistosomes in culture was maintained for at least 24 hr when L-glutamine was the only carbon source available to the worms. Under these conditions, motility was reduced when parasites were exposed to a respiratory inhibitor such as KCN, antimycin A, rotenone, or oligomycin, but it was completely restored by the addition of glucose to the medium. These results suggest that while the schistosome is capable of limited aerobic energy-generating processes under certain conditions, survival is not contingent upon these processes in the presence of glucose.     

女性需氧菌阴道炎临床及实验室诊断方法研究进展

需氧菌阴道炎(AV)是近几年才被发现的一种下生殖道感染,AV患者多主诉阴道瘙痒、灼热、性交痛,阴道分泌物稀薄脓性、黄色或黄绿色,氢氧化钾试验阴性,阴道黏膜充血,严重者有散在出血点或溃疡.其临床症状体征和滴虫性阴道炎(TV)患者极为相似,仅通过临床症状体征诊断易造成误诊.由于AV和TV致病菌的抗生素敏感性不同,只有通过明确诊断才能指导临床合理用药.现将国内外用于AV诊断的一些临床及实验室诊断方法做一概述,供临床医生参考.     

Hemoglobin concentration and aerobic work capacity in women following induced erythrocythemia

The effect of induced erythrocythemia on hemoglobin concentration ([Hb]) and aerobic work capacity was determined for nine women. Cycle tests were performed at prereinfusion (T1), 2 days after a placebo infusion (T2), 2 days postreinfusion of 334 ml of red blood cells (T3), 8 days postreinfusion (T4), and 14 days postreinfusion (T5). T1 and T2 responses did not differ, negating a placebo effect. [Hb] increased from 12.7 g X dl at T1 to 14.7 g X dl at T3 and then remained constant at T4 and T5. Hematocrit increased from 38.1% at T1 to 44.9% at T3 and then remained constant at T4 and T5. Submaximal O2 uptake (VO2) and stroke volume (SV) did not change from T1 through T5. Submaximal cardiac output (Q) and heart rate (HR) decreased from T1 to T3 and then remained constant at T4 and T5. Arteriovenous O2 difference increased from T1 to T3 and then remained constant at T4 and T5. Maximal VO2 was greater at T3 (2.65 l X min-1), T4 (2.66 l X min-1), and T5 (2.60 l X min-1) than at T1 (2.41 l X min-1). Physical work capacity was greater at T3 (10,740 kg X m), T4 (10,980 kg X m), and T5 (10,380 kg X m) than at T1 (8,747 kg X m). Maximal values for Q, HR, and SV were unchanged from T1 through T5. At maximum, arteriovenous O2 difference and Hb flow rate increased from T1 to T3 and then remained constant at T4 and T5. The greater postreinfusion [Hb] improved O2 transport capacity and appeared to regulate circulatory responses.     

The physiological effects of caffeine in women during treadmill walking

Although the effects of caffeine ingestion on athletic performance in men have been studied extensively, there is limited previous research examining caffeine's effects on women of average fitness levels participating in common modes of physical activity. The purpose of this study was to determine the effect of 2 levels of caffeine dosage on the metabolic and cardiorespiratory responses to treadmill walking in women. Subjects were 20 women (19-28 years of age) of average fitness, not habituated to caffeine. Each subject was assigned randomly a 3-mg x kg(-1) dose of caffeine, 6-mg x kg(-1) dose of caffeine, and placebo for 3 trials of moderate steady-state treadmill walking at 94 m x min(-1) (3.5 mph). Steady-state rating of perceived exertion (RPE), heart rate (HR), respiratory exchange ratio (RER), weight-relative VO2, %VO2max reserve (%VO2R), and rate of energy expenditure (REE) were measured during each trial. Repeated measures analysis of variance revealed that a 6-mg x kg(-1), but not a 3-mg x kg(-1) dose of caffeine increased VO2 (p = 0.04), REE (p = 0.03), and %VO2R (p = 0.03), when compared to the placebo. Caffeine had no effect on RPE, HR, or RER. No significant differences were observed between the placebo trials and the 3-mg x kg(-1) dose trials. Although a 6-mg x kg(-1) dose of caffeine significantly increased REE during exercise, the observed increase (approximately 0.23 kcal x min(-1)) would not noticeably affect weight loss. Because caffeine had no effect on RPE, it would not be prudent for a trainer to recommend caffeine in order to increase a woman's energy expenditure or to decrease perception of effort during mild exercise. These data also demonstrate that caffeine intake should not interfere with monitoring walking intensity by tracking exercise heart rate in women.     

Maximal aerobic capacity across age in healthy Hispanic and Caucasian women.

We tested the hypothesis that the age-related decline in maximal aerobic capacity, as measured by maximal oxygen uptake (VO(2 max)), is greater in Hispanic than in Caucasian women. We studied 146 healthy sedentary women aged 20-75 yr: 53 Hispanic (primarily of Mexican descent) and 93 Caucasian (non-Hispanic white). The groups did not differ in mean age, body mass, percent body fat, estimated physical activity-related energy expenditure, or education-based socioeconomic status (SES). During maximal exercise, respiratory exchange ratio, rating of perceived exertion, and percent predicted maximal heart rate were similar across age and ethnicity, suggesting equivalent maximum voluntary efforts in all subjects. VO(2 max) (ml x kg(-1) x min(-1)) was inversely related to age (P < 0.01) in Caucasian (r =-0.68) and Hispanic (r = -0.61) women. The absolute rate of decline in VO(2 max) with age was the same in the two groups (-0.31 ml x kg(-1) x min(-1) x yr(-1)). The relative rate of decline (% from age 25 yr) also was similar in the Caucasian (-9.0%) and Hispanic (-9.2%) women. When subjects of all ages were pooled, mean levels of VO(2 max) were similar in the two groups (approximately 28 ml x kg(-1) x min(-1)). These results, the first to our knowledge in Hispanics, indicate that mean levels of VO(2 max), as well as the rate of decline in VO(2 max) with age, are similar in healthy sedentary Hispanic and Caucasian women of similar SES. Thus it does not appear that Hispanic ethnicity per se modulates maximal aerobic capacity in this population.