.-We investigated the effects of aging on the elastic properties of lung tissue and the chest wall, simultaneously quantifying the contribution of each component to static inspiratory muscle work in resting and exercising adults. We further evaluated the interaction of aging and habitual physical activity on respiratory mechanics. Static lung volumes and elastic properties of the lung and chest wall (pressure-volume relaxation maneuvers) in 29 chronically sedentary and 29 habitually active subjects, grouped by age, were investigated: young (Y, 20 -30 years), middle-aged (M, 40 -50 years), and older (O, Ͼ60 years). Using static pressure-volume data, we computed the elastic work of breathing (joules per liter, J ⅐ l Ϫ1 ), including inspiratory muscle work, over resting and exercising tidal volume excursions. Elastic work of the lung (Y ϭ 0.79 Ϯ 0.05; M ϭ 0.47 Ϯ 0.05; O ϭ 0.43 Ϯ 0.05 J ⅐ l Ϫ1 ) and chest wall (Y ϭ Ϫ0.49 Ϯ 0.06; M ϭ Ϫ0.12 Ϯ 0.07; O ϭ 0.04 Ϯ 0.05 J ⅐ l Ϫ1 ) changed significantly with age (P Ͻ 0.05). With aging, a parallel displacement of the chest wall pressure-volume curve resulted in a shift from energy being stored primarily during expiration to energy storage during inspiration, and driving expiration, both at rest and during exercise. Although deviating significantly from young adults, this did not significantly elevate static inspiratory muscle work but resulted in a redistribution of the tissues on which this work was performed and the phase of the respiratory cycle in which it occurred. Nevertheless, static inspiratory muscle work remained similar across age groups, at rest and during exercise, and habitual physical activity failed to influence these changes. chest wall; compliance; respiratory mechanics; work of breathing QUANTITATIVE STUDIES of the respiratory system indicate that aging lungs contain fewer, but larger, alveoli (1, 40), respiratory muscle strength is reduced (5, 10), there is an increased calcification of the intrathoracic joints (9, 11), and the diaphragmatic contribution to ventilation is elevated, particularly during exercise (35). These changes are likely to affect the mechanics of the respiratory system and, in turn, modify the static work of breathing. Accordingly, the literature contains several reports that aging humans experience a reduction in lung tissue elastic work (14,15,38).We have had particular interest in the possible effect that a greater calcification of the aging rib cage joints may have on chest wall stiffness, since a more rigid chest wall would increase the static work of breathing, similar to that seen in restrictive pulmonary disorders or chest strapping (8). Such changes may possibly result in a ventilatory limit to exercise. However, there has been very little research focusing on changes in chest wall mechanics in aging humans (27,29,35), with only one study specifically concerned with changes in chest wall elastic work during senescence (21); this project demonstrated that aging was accompanied by an increase in chest wall elastic work. Indeed, ...

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As no significant restriction to exercise performance or respiratory mechanics was found when subjects wore sports brassieres, it was concluded that active females should wear a sports brassiere during physical activity to reduce breast motion and related breast pain.

Protocatechuic acid (PCA), a strong antioxidant, has been reported for its cardiovascular-protective effects. This study aimed to investigate the effects of PCA administration on vascular endothelial function, mediated by insulin and insulin-like growth factor-1 (IGF-1), and antioxidant activities in aging hypertension. Thirty-six-week-old male aging spontaneously hypertensive rats were randomly divided into vehicle control (SHR) and PCA (SHR+PCA) groups, while age-matched Wistar–Kyoto rats (WKY) served as the normotensive vehicle control group. The oral PCA (200 mg/kg/day) was administered daily for a total of 12 weeks. When the rats reached the age of 48 weeks, the rat aortas were isolated for the evaluation of vascular reactivity and Western blotting. Also, nitric oxide (NO) production and antioxidant activities were examined among the three groups. The results showed that, when compared with the SHR group, the insulin-induced and IGF-1-induced vasorelaxation were significantly improved in the SHR+PCA group. There was no significant difference in the endothelium-denuded vessels among the three groups. After the pre-incubation of phosphatidylinositol 3-kinase (PI3K) or NO synthase (NOS) inhibitors, the vasorelaxation was abolished and comparable among the three groups. The protein levels of insulin receptors, IGF-1 receptors, phospho-protein kinase B (p-Akt)/Akt, and phospho-endothelial NOS (p-eNOS)/eNOS in aortic tissues were significantly enhanced in the SHR+PCA group when compared with the SHR group. Moreover, significant improvements of nitrate/nitrite concentration and antioxidant activities, including superoxide dismutase, catalase, and total antioxidants, were also found in the SHR+PCA group. In conclusion, the 12 weeks of PCA administration remarkably improved the endothelium-dependent vasorelaxation induced by insulin and IGF-1 in aging hypertension through enhancing the PI3K–NOS–NO pathway. Furthermore, the enhanced antioxidant activities partly contributed to the improved vasorelaxation.

BackgroundSeveral studies on Caucasian volunteers have proven that milk is an effective recovery drink for athletes. Such benefit, however, cannot be directly applied to the lactose-intolerant Asian population. This study investigated the effects of ingesting water (WT), sports drink (SPD) and lactose-free milk (LFM) on cycling capacity.MethodsTen healthy young men completed 3 randomized experimental trials. Each trial consisted of an intermittent glycogen depleting session, a 2 h recovery period during which they ingested the test drink, followed by cycling at 70% of their maximum oxygen consumption (VO2max) to volitional exhaustion. Each trial was separated by at least one week.ResultsThere were no complaints or symptoms of lactose intolerance during any of the trials. The cycling periods were different (p < 0.05) amongst the 3 trials, namely, lactose-free milk (LFM; 69.6 ± 14.0 min), sports drink (SPD; 52.1 ± 11.6 min), and water (WT; 36.0 ± 11.1 min), respectively. The VO2 and VCO2 of LFM (30 ± 4 and 29 ± 4 ml/kg/min) were lower (p < 0.05) than that of SPD (34 ± 4 and 34 ± 4 ml/kg/min) and WT (35 ± 4 and 33 ± 5 ml/kg/min). There were no differences (p = 0.45) in VO2 and VCO2 between SPD and WT. Mean rating of perceived exertion was lowest in LFM (14 ± 5; p < 0.05), while no difference was found between the other two trials (SPD: 16 ± 4 and WT: 16 ± 4; p = 0.18).ConclusionLactose-free milk is likely to be an effective recovery drink for enhancing subsequent cycling capacity in lactose intolerant Asian males.

BackgroundThe purpose of this study was to investigate the combined 17β-estradiol (E2) and exercise training on cardiac pro-survival and anti-apoptotic pathways in ovariectomized rats.MethodsFifty-six female Sprague–Dawley rats were divided into a sham-operated (Sham), a bilaterally ovariectomized (OVX), an OVX treated with E2 (OVX-E2; 10μg/kg/day), and an OVX with E2 and treadmill exercise training (OVX-E2-EX; 60 min/day, 5 days/week) for 10 weeks. Following 10 weeks of exercise training, rat hearts were isolated for the evaluation of Histopathological analysis, TUNEL assay, and Western blotting.ResultsThe protein levels of estrogen receptor α (ERα), estrogen receptor β (ERβ), insulin-like growth factor 1 (IGF-1), IGF-1 receptor (IGF-1R), phospho-phosphatidylinositol 3-kinase (p-PI3K) (estrogen receptors/IGF-1-related survival pathway) were significantly increased in either the OVX-E2 or OVX-E2-EX group when compared with the OVX group. The protein levels of B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra-large (Bcl-xL) and phosphorylated-Bad (p-Bad) (Bcl-2 family survival pathway) were significantly increased in the OVX-E2-EX group when compared with the OVX group. Only the p-Bad was significantly increased in the OVX-E2 group when compared with the OVX group. The protein levels of truncation of Bid (t-Bid), Bcl-2-associated death promotor (Bad), Bcl-2-associated X protein (Bax), Cytochrome c, caspases-9, and caspases-3 (mitochondria-dependent apoptotic pathway), as well as the protein levels of tumor necrosis factor-α (TNF-α), Fas ligand, Fas receptors, Fas-associated death domain (FADD), activated caspase-8 and activated caspase-3 (Fas receptor–dependent apoptotic pathway) were significantly decreased in either the OVX-E2 or OVX-E2-EX group when compared with the OVX group. Furthermore, when compared with the OVX-E2 group, the protein levels of ERβ, IGF-1, IGF-1R, Bcl-2 and Bcl-xL were further enhanced in the OVX-E2-EX group as well as the protein levels of Cytochrome c, Fas receptors, FADD, activated caspase-8, activated caspase-9 and activated caspase-3 were further decreased in the OVX-EX-E2 group.ConclusionsCombined E2 and exercise training exhibited a positive effect of protection on ovariectomy-induced cardiac apoptosis by enhancing ERβ-related survival pathways, which might provide a more effective therapeutic effect on cardiac protection in bilaterally oophorectomized or menopausal women than E2 treatment only.

Abstract. [Purpose] To determine the effects of a home-based walking program on lower extremity muscle strength of hemodialysis patients.[Methods] Twenty-six hemodialysis patients were divided into a training and a control group. Lower extremity muscle strength was measured using a back and leg dynamometer prior to and at the 4th, 8th, and 12th weeks of the study period in both groups. The training group performed the home-based walking program, an individually prescribed walking program which progressively increased in duration by incrementing the number of steps by 10% every two weeks. Subjects in the control group were asked to keep to their routine activities, as much as possible, during the study period.[Results] Lower extremity muscle strength in the training group remarkably increased from 52 kg at baseline to 68 kg at the 12th week (4th week = 58 kg, 8th week = 63 kg), whereas no change in the control group was found (baseline = 51 kg, 4th week = 52 kg, 8th week = 51 kg, 12th week = 48 kg).[Conclusion] A homebased walking exercise program improved lower extremity muscle strength of hemodialysis patients. Patients who have stable medical conditions should be encouraged to participate in this home-based walking exercise program to improve their abilities to perform activities of daily living.

Background: Previous studies have consistently shown that oral supplementation of deep ocean minerals (DOM) improves vascular function in animals and enhances muscle power output in exercising humans.Purpose: To examine the effects of DOM supplementation on the cerebral hemodynamic response during physical exertion in young and middle-aged men.Design: Double-blind placebo-controlled crossover studies were conducted in young (N = 12, aged 21.2 ± 0.4 years) and middle-aged men (N = 9, aged 46.8 ± 1.4 years). The counter-balanced trials of DOM and Placebo were separated by a 2-week washout period. DOM and Placebo were orally supplemented in drinks before, during, and after cycling exercise. DOM comprises desalinated minerals and trace elements from seawater collected ~618 m below the earth's surface.Methods: Cerebral hemodynamic response (tissue hemoglobin) was measured during cycling at 75% VO2max using near infrared spectroscopy (NIRS).Results: Cycling time to exhaustion at 75% VO2max and the associated plasma lactate response were similar between the Placebo and DOM trials for both age groups. In contrast, DOM significantly elevated cerebral hemoglobin levels in young men and, to a greater extent, in middle-aged men compared with Placebo. An increased neutrophil to lymphocyte ratio (NLR) was observed in middle-aged men, 2 h after exhaustive cycling, but was attenuated by DOM.Conclusion: Our data suggest that minerals and trace elements from deep oceans possess great promise in developing supplements to increase the cerebral hemodynamic response against a physical challenge and during post-exercise recovery for middle-aged men.