Gonadal hormones and semen quality in male runners. A volume threshold effect of endurance training.

Eleven high mileage runners (HR) (108.0 +/- 4.5 km.wk-1), 9 moderate mileage runners (MR) (54.2 +/- 3.7 km.wk-1) and 10 sedentary controls (SC) of similar age (28.3 +/- 1.5 yr) were studied to evaluate the effects of volume of endurance training on reproductive function in male runners. Levels of reproductive, adrenal and thyroid hormones were measured during a 1-hr period of serial blood sampling (q20 min) and urinary excretion of 24-hr luteinizing hormone (uLH) was determined on two separate days. Semen exams and sperm penetration of standard cervical mucus (Penetrak) were performed 2-5 times. Levels of total testosterone (TT) and free testosterone (FT) were significantly lower in HR (15.3 +/- 1.3 nmol.l-1 and 60.2 +/- 5.1 pmol.l-1) compared to MR (21.4 +/- 1.6 nmol.l-1 and 86.0 +/- 6.1 pmol.l-1) and SC (19.5 +/- 0.9 nmol.l-1 and 75.9 +/- 3.6 pmol.l-1). No differences (p > 0.05) were found in uLH, serum LH, follicle-stimulating hormone (FSH), and prolactin (PRL) among the three groups. No other hormonal differences (p > 0.05) were observed among the groups. Total motile sperm count and density were lower (p < 0.05) in HR than SC. Decreased (p < 0.0006) sperm motility and an increased (p < 0.004) population of immature sperm and round cells were observed in HR compared to MR and SC. Sperm penetration of bovine cervical mucus was also decreased (p < 0.024) in HR compared to SC. Volume of training, defined by km.wk-1 run, was significantly correlated to sperm motility, density and number of round cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Body fluid balance in dehydrated healthy older men: thirst and renal osmoregulation.

We examined osmotic control of thirst and free water clearance in healthy older (65+, n = 10) and younger (Y, n = 6) subjects during a 3-h rehydration period after an approximately 2.4% decrease in body weight. Plasma volume (PV), plasma osmolality (Posm), renal function, and thirst were measured before and after dehydration and during rehydration. In 65+, baseline PV was lower (43.1 +/- 1.6 vs. 48.1 +/- 2.5 ml/kg), Posm was higher (287 +/- 1 vs. 281 +/- 2 mosmol/kgH2O), and perceived thirst was lower than in Y. During dehydration, the osmotic threshold for increased thirst was shifted to a higher Posm in 65+. Total fluid intake was greater in Y than in 65+ (16.6 +/- 4.1 vs. 8.9 +/- 2.0 ml/kg); however, the relation between thirst and the rate of fluid intake was identical. Thus the blunted rehydration in 65+ is related to a lower overall sensation of thirst. The stimulus-response characteristics of osmotic control of free water clearance was similar in 65+ and Y; however, 65+ operated around a higher Posm and on a less-steep portion of the stimulus-response curve. These data support the hypothesis that the hyperosmotic hypovolemic state of healthy older individuals is not a result of a simple water deficit but represents a shift in the operating point for control of body fluid volume and composition.

Short-term effect of dynamic exercise on arterial blood pressure.

BACKGROUND: To quantify the duration of postexercise hypotension at different exercise intensities, we studied six unmedicated, mildly hypertensive men matched with six normotensive controls. METHODS AND RESULTS: Each subject wore a 24-hour ambulatory blood pressure monitor at the same time of day for 13 consecutive hours on 3 different days. On each of the 3 days, subjects either cycled for 30 minutes at 40% or 70% maximum VO2 or performed activities of daily living. There was no intensity effect on the postexercise reduction in blood pressure, so blood pressure data were combined for the different exercise intensities. Postexercise diastolic blood pressure and mean arterial pressure were lower by 8 +/- 1 (p less than 0.001) and 7 +/- 1 mm Hg (p less than 0.05), respectively, than the preexercise values for 12.7 hours in the hypertensive group. These variables were not different before and after exercise in the normotensive group. Systolic blood pressure was reduced by 5 +/- 1 mm Hg (p less than 0.05) for 8.7 hours after exercise in the hypertensive group. In contrast, systolic blood pressure was 5 +/- 1 mm Hg (p less than 0.001) higher for 12.7 hours after exercise in the normotensive group. When the blood pressure response on the exercise days was compared with that on the nonexercise day, systolic blood pressure (135 +/- 1 versus 145 +/- 1 mm Hg) and mean arterial pressure (100 +/- 1 versus 106 +/- 1 mm Hg) were lower (p less than 0.05) on the exercise days in the hypertensive but not in the normotensive group. We found a postexercise reduction in mean arterial pressure for 12.7 hours independent of the exercise intensity in the hypertensive group. Furthermore, mean arterial pressure was lower on exercise than on nonexercise days in the hypertensive but not in the normotensive group. CONCLUSION: These findings indicate that dynamic exercise may be an important adjunct in the treatment of mild hypertension.

The effect of sodium meclofenamate in premenstrual asthma: a controlled clinical trial.

We speculated that changes in endogenous prostaglandin synthesis might be responsible for the syndrome of premenstrual asthma (worsening of asthma in relation to menstruation). To test our hypothesis, we compared the effects of sodium meclofenamate, a prostaglandin synthesis inhibitor, and placebo on premenstrual asthma in a 4-month, double-blind, crossover study of 17 women with asthma. Day-by-day evaluation revealed that peak expiratory flow reached a nadir during menstruation on both meclofenamate and placebo therapy and varied inversely with menstrual symptoms and asthma symptoms. Meclofenamate therapy resulted in significant improvement in peak expiratory flow during the early premenstrual period but had no treatment effect on the exacerbation of asthma during the late premenstrual period and early menstruation. The overall improvement in pulmonary function caused by meclofenamate therapy was correlated with the treatment effect on menstrual symptoms. Meclofenamate caused a small, nonsignificant decrease in use of theophylline and oral beta-agonist agents, whereas corticosteroid use increased slightly but not significantly. This study demonstrates the temporal relationship between menstrual symptoms and asthma. The study also demonstrates that inhibition of prostaglandin synthesis does not prevent exacerbation of asthma in relation to menstruation.

The effects of acute exercise on subsequent cigarette smoking.

The present study was conducted to examine the effects of acute aerobic exercise on smoking behavior. On alternate days, 10 healthy young smokers were subjected to half an hour of sustained high exercise (about 56% of maximum work capacity) or of low exercise (about 28% of maximum, simulating normal daytime activity). During the high-exercise condition, there were pronounced increases in physiological markers of physical activity such as mean work, heart rate, and lactic acid as well as elevations in circulating hormones (norepinephrine, epinephrine, and immunoreactive beta-endorphin and cortisol) known to be affected by vigorous exercise. Despite a trend toward decreased desire for cigarettes after the high exercise condition, there were no differences in plasma nicotine levels following the smoking of a usual-brand cigarette 35 min later. The sustained effects of the two exercise conditions were also similar: plasma cotinine levels 24 hr later (reflecting nicotine intake over the entire exercise day) revealed no significant differences between high and low exercise.

Morbidity in asthma in relation to the menstrual cycle.

After observing three cases of severe recurrent exacerbations of asthma in relation to menstruation, we conducted a survey among women with asthma inquiring about the relationship of asthma symptoms to the menstrual cycle. Of 57 women with asthma, 19 (33%) had significant worsening (p = 0.006) of total pulmonary symptom scores during either the premenstrual period, the menstrual period, or both with maximum increase in dyspnea, wheezing, and chest tightness during the premenstrual period (p = 0.002). The other 38 (66%) women noted no such changes in their asthma. Logistic regression analysis comparing women with and without worsening of their asthma around menstruation revealed that the former group reported significantly more severe wheezing in general (p less than 0.05) and also more severe pulmonary symptoms during the premenstrual period (p less than 0.05). Of the women whose asthma was affected by menses, 13 (68%) had been hospitalized for asthma but only 10 (26%) of the women who were unaffected (p = 0.002). Both dysmenorrhea scores and premenstrual syndrome scores correlated significantly with baseline pulmonary symptom scores in the premenstrual asthma group. It appears that asthma morbidity is affected by the menstrual cycle in a subgroup of women with asthma.

Lung injury produced by immune complexes of varying composition.

Immune complexes consisting of rabbit antibody to bovine serum albumin (BSA) have been made up at 1X, 3X, 6X, 8X, and 20X antigen equivalence. The complement fixing activity of these complexes is inversely proportional to the amount of antigen present in the complexes, and, as expected, solubility of the complexes progressively increases with increasing amounts of antigen. The ability of these complexes to induce acute pulmonary injury and inflammatory responses has been quantitatively assessed. Complexes preformed at antigen equivalence are the most damaging to lung, correlating with their complement fixing activity. When the antigen concentration in the complexes is increased 3 to 6 times beyond the point of equivalence, the phlogistic activity of the complexes drops off rapidly, as demonstrated by a sharp decline in the changes in vascular permeability, hemorrhage, and morphologic evidence of inflammation. These studies provide the first evidence that changing the physicochemical parameters of preformed immune complexes by simply altering the ratio of antigen to antibody can dramatically alter the phlogistic properties of immune complexes for pulmonary tissue.

Lung and dermal vascular injury produced by preformed immune complexes.

Tissue injury was studied in rat lung and in the dermal vasculature after the injection of preformed, heterologous immune complexes. In lung, these complexes induced an acute, hemorrhagic alveolitis with large numbers of neutrophils. There were marked increases in permeability and extensive intrapulmonary hemorrhage. Similar changes of lesser magnitude developed at sites of dermal injection of immune complexes. The lung and skin reactions were complement- and neutrophil-dependent. The tissue damage in lung, as measured by permeability changes and development of hemorrhage, appeared to intensify during the first 24 hours and then began to wane. By the second and third day after the acute insult, permeability changes and hemorrhage had returned toward control values. Inflammatory, tissue-damaging reactions did not develop in lung or dermis if heat-aggregated bovine serum albumin was injected in place of immune complexes. This model permits the direct study of lung and vascular injury induced by preformed immune complexes.