Journal of Applied Physiology (J APPL PHYSIOL )

Publisher: American Physiological Society (1887- ), American Physiological Society

Description

The Journal of Applied Physiology publishes original papers that deal with diverse areas of research in applied physiology, especially those emphasizing adaptive and integrative mechanisms. Adaptive physiology includes 1) inherent adaptations such as those related to development, aging, and pathophysiological conditions and 2) adaptations to the external environment such as those occurring with exercise, microgravity, hypoxia, hypo- and hyperbaria, and hypo- and hyperthermic conditions. Integrative physiology includes 1) horizontal integration across organ systems and 2) vertical integration from molecule to cell to organ. In all areas of applied physiology, the use of cutting-edge techniques including molecular and cellular biology is strongly encouraged.

Impact factor 3.43

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    Impact factor
  • 5-year impact
    4.16
  • Cited half-life
    0.00
  • Immediacy index
    0.52
  • Eigenfactor
    0.05
  • Article influence
    1.24
  • Website
    Journal of Applied Physiology website
  • Other titles
    Journal of applied physiology (Bethesda, Md.: 1985), Journal of applied physiology
  • ISSN
    8750-7587
  • OCLC
    11603017
  • Material type
    Periodical, Internet resource
  • Document type
    Journal / Magazine / Newspaper, Internet Resource

Publisher details

American Physiological Society

  • Pre-print
    • Author cannot archive a pre-print version
  • Post-print
    • Author cannot archive a post-print version
  • Conditions
    • NIH, Wellcome Trust, HHMI, MRC and BBSRC authors will on their behalf have the Publisher's version/PDF deposited in PubMed Central for release 12 months after publication
    • Publisher's version/PDF cannot be used
  • Classification
    ​ white

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: Periodic breathing is frequent in heart failure or ventilatory disorders during sleep, and common during sleep at high altitude, but has been rarely studied in wakefulness and during exercise. A retrospective analysis of ventilation from hypoxia exercise tests was realized in 82 healthy subjects separated into two groups with either high or low ventilatory response to hypoxia at exercise (HVRe). A fast Fourier transform spectral analysis of the breath-by-breath ventilation (V̇e) signal, O2 saturation, and end-tidal PCO2 evidenced a periodic pattern with a period of 11.1 to 12.0 s. The peak power of the V̇e spectrum was higher in the high HVRe group (P < 0.001). A prospective study (25 subjects) was performed to evaluate the influence of cardiorespiratory factors on the amplitude and period of oscillations in various conditions of exercise (20 to 40% maximal aerobic power) and hypoxia (0 to 4,000 m altitude). The period of V̇e was shorter at exercise (vs. rest, P < 0.001) and hypoxia (vs. normoxia, P < 0.001), and inversely related with cardiac output and V̇e (P < 0.001). V̇e peak power was higher at exercise (P < 0.001) and hypoxia (P < 0.001), and was positively related with cardiac output and V̇e (P < 0.001). V̇e peak power in hypoxia was positively related with the ventilatory response to CO2 (HCVR). This novel observation suggests that healthy subjects demonstrate a spontaneous periodic breathing, not clearly observable at rest and in normoxia, but triggered by hypoxic exercise. The periodic pattern is enhanced in subjects with high HVRe and high HCVR, suggesting that oxygen and CO2 play synergistic roles in the modulation of these oscillations. Copyright © 2015 the American Physiological Society.
    Journal of Applied Physiology 01/2015; 118(1):115-23.
  • Journal of Applied Physiology 01/2015;
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    ABSTRACT: Whole body fat oxidation increases during exercise. However, 24-h fat oxidation on a day with exercise often remains similar to that of sedentary day, when energy intake is increased to achieve an energy-balanced condition. The present study aimed to examine a possibility that time of the day when exercise is performed makes differences in 24-h fat oxidation. As a potential mechanism of exercise affecting 24-h fat oxidation, its relation to exercise-induced transient energy deficit was examined. Nine young male endurance athletes underwent three trials of indirect calorimetry using a metabolic chamber, in which they performed a session of 100 min of exercise before breakfast (AM), after lunch (PM), or two sessions of 50 min of exercise before breakfast and after lunch (AM/PM) at 65% of maximal oxygen uptake. Experimental meals were designed to achieve individual energy balance. Twenty-four-hour energy expenditure was similar among the trials, but 24-h fat oxidation was 1,142 ± 97, 809 ± 88, and 608 ± 46 kcal/24 h in descending order of its magnitude for AM, AM/PM, and PM, respectively (P < 0.05). Twenty-four-hour carbohydrate oxidation was 2,558 ± 110, 2,374 ± 114, and 2,062 ± 96 kcal/24 h for PM, AM/PM, and AM, respectively. In spite of energy-balanced condition over 24 h, exercise induced a transient energy deficit, the magnitude of which was negatively correlated with 24-h fat oxidation (r = -0.72, P < 0.01). Similarly, transient carbohydrate deficit after exercise was negatively correlated with 24-h fat oxidation (r = -0.40, P < 0.05). The time of the day when exercise is performed affects 24-h fat oxidation, and the transient energy/carbohydrate deficit after exercise is implied as a factor affecting 24-h fat oxidation. Copyright © 2015 the American Physiological Society.
    Journal of Applied Physiology 01/2015; 118(1):80-5.
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    ABSTRACT: Heat treatments (HT) and the induction of heat shock proteins (HSPs) improve whole body and skeletal muscle insulin sensitivity while decreasing white adipose tissue (WAT) mass. However, HSPs in WAT have been understudied. The purpose of the present study was to examine patterns of HSP expression in WAT depots, and to examine the effects of a single in vivo HT on WAT metabolism. Male Wistar rats received HT (41°C, 20 min) or sham treatment (37°C), and 24 h later subcutaneous, epididymal, and retroperitoneal WAT depots (SCAT, eWAT, and rpWAT, respectively) were removed for ex vivo experiments and Western blotting. SCAT, eWAT, and rpWAT from a subset of rats were also cultured separately and received a single in vitro HT or sham treatment. HSP72 and HSP25 expression was greatest in more metabolically active WAT depots (i.e., eWAT and rpWAT) compared with the SCAT. Following HT, HSP72 increased in all depots with the greatest induction occurring in the SCAT. In addition, HSP25 increased in the rpWAT and eWAT, while HSP60 increased in the rpWAT only in vivo. Free fatty acid (FFA) release from WAT explants was increased following HT in the rpWAT only, and fatty acid reesterification was decreased in the rpWAT but increased in the SCAT following HT. HT increased insulin responsiveness in eWAT, but not in SCAT or rpWAT. Differences in HSP expression and induction patterns following HT further support the growing body of literature differentiating distinct WAT depots in health and disease. Copyright © 2015 the American Physiological Society.
    Journal of Applied Physiology 01/2015; 118(1):98-106.
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    ABSTRACT: Inhaled nitric oxide (INO) improves ventilation-perfusion matching and alleviates pulmonary hypertension in patients with acute respiratory distress syndrome. However, outcome has not yet been shown to improve, and non-response is common. A better understanding of the mechanisms by which INO acts, may guide in improving treatment with INO in patients with severe respiratory failure. We hypothesized that INO may act not only by vasodilation in ventilated lung regions, but also by causing vasoconstriction via endothelin (ET-1) in atelectatic, non-ventilated lung regions. This was studied in 30 anesthetized, mechanically ventilated piglets. The fall in oxygenation and rise in pulmonary artery pressure during a sepsis-like condition (infusion of endotoxin) were blunted by INO 40ppm. Endotoxin infusion increased serum ET-1, and INO almost doubled the ratio between mRNA expression of endothelin receptor A (mediating vasoconstriction) and B (mediating vasodilation and clearance of ET-1) (ET-A/ET-B) in atelectatic lung regions. INO caused a shift in blood flow away from atelectatic lung regions in the endotoxemic piglets, but not during ET receptor antagonism. We conclude that INO in short term experiments, in addition to causing selective pulmonary vasodilation in ventilated lung regions, also increases the ET-A/ET-B mRNA expression ratio in lung tissue. This might augment the vasoconstriction in atelectatic lung regions, enhancing the redistribution of pulmonary blood flow to ventilated lung regions which are reached by INO. Such vasoconstriction may be an important additional factor explaining the effect of INO. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: NA. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: Apnea is nearly universal among very low birth weight (VLBW) infants, and the associated bradycardia and desaturation may have detrimental consequences. We describe here very long (>60 second) central apnea events (VLAs) with bradycardia and desaturation, discovered using a computerized detection system applied to our database of over 100 infant-years of electronic signals. Results: 86 VLAs occurred in 29 out of 335 VLBW infants. 18 of the 29 infants had a clinical event or condition possibly related to the VLA. Most VLAs occurred while infants were on nasal continuous positive airway pressure, supplemental oxygen and caffeine. Apnea alarms on the bedside monitor activated in 66% of events, on average 28 seconds after cessation of breathing. Bradycardia alarms activated late, on average 64 seconds after cessation of breathing. Prior to VLAs oxygen saturation was unusually high, and during VLAs oxygen saturation and heart rate fell unusually slowly. We give measures of the relative severity of VLAs, and theoretical calculations that describe the rate of decrease of oxygen saturation. Conclusions: Clinical - Very long apnea events with bradycardia and desaturation are not rare. Apnea alarms failed to activate for about 1/3 of VLAs. It appears that NICU personnel respond quickly to bradycardia alarms, but not consistently to apnea alarms. We speculate that more reliable apnea detection systems would improve patient safety in the NICU. Physiological - The slow decrease of oxygen saturation is consistent with a physiological model based on assumed high values of initial oxygen saturation. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: The aim of the present study was to examine the impact of training status on the ability to induce a lipopolysaccharide (LPS)-induced inflammatory response systemically as well as in skeletal muscle (SkM) and adipose tissue (AT) in human subjects. Methods: Seventeen young (23.8 ± 2.5 years of age) healthy male subjects were included in the study with eight subjects assigned to a trained (T) group and nine subjects assigned to an untrained (UT) group. On the experimental day, catheters were inserted in the femoral artery and vein of one leg for blood sampling and a bolus of 0.3 ng LPS•kg-1 body weight was injected into an antecubital vein in the forearm. Femoral arterial blood flow was measured before (Pre) the LPS injection and continuously throughout the experiment by Ultrasound Doppler and arterial and venous blood samples were drawn Pre and 30, 60, 90 and 120 min after the LPS injection. Vastus lateralis muscle and abdominal subcutaneous AT biopsies were obtained Pre, 60 and 120 min after the LPS injection. Results: LPS increased the systemic plasma TNFα and IL-6 level as well as the TNFα and IL-6 mRNA content in SkM and AT of both UT and T. Whereas the LPS-induced inflammatory response in SkM was enhanced in T subjects relative to UT, the inflammatory response systemically and in AT was somewhat delayed in T subjects relative to UT. Conclusion: The present findings highlight that training status affects the ability to induce a LPS-induced acute inflammatory response in a tissue-specific manner. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: N/A. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: Children with the obstructive sleep apnea syndrome (OSAS) have impaired respiratory afferent cortical processing during sleep that persists after treatment of OSAS. However, it is unknown whether this impairment is present during wakefulness and if so, whether it improves after OSAS treatment. We hypothesized that children with OSAS, during wakefulness, have abnormal cortical processing of respiratory stimuli manifested by blunted respiratory-related evoked potentials (RREP) and that this resolves after OSAS treatment. We measured RREP during wakefulness in 26 controls and 21 children with OSAS before and after treatment. 13 participants with OSAS repeated testing 3-6 months after adenotonsillectomy. RREP were elicited by interruption of inspiration by total occlusion, and 30 and 20 cm H2O/L/s resistances. Nf at Fz latency elicited by occlusion was longer in children with OSAS at baseline compared to controls (78.8±24.8 vs. 63.9±19.7 ms, p = 0.05). All other peak amplitudes and latencies were similar between the two groups. After OSAS treatment, Nf at Fz latency elicited by 30 cm H2O/L/s decreased significantly (before, 88±26 vs. 71±25 ms after, p =0.02) as did that elicited by 20 cm H2O/L/s (85±27 vs. 72±24 ms, p= 0.004). The amplitude of N1 at Cz elicited by occlusion increased from -3.4±5.6 to -7.4±3 µV (p=0.049) after treatment. We concluded that children with OSAS have partial delay of respiratory afferent cortical processing during wakefulness that improves after treatment. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: The midluteal (ML) phase of the ovarian cycle is often sympathoexcitatory when compared to the early follicular (EF) phase. We recently reported that 24-hour total sleep deprivation (TSD) augmented cardiovascular reactivity in both men and women, but that sex differences existed in resting muscle sympathetic nerve activity (MSNA) responses to TSD. In the present study, we hypothesized increased resting MSNA and augmented cardiovascular reactivity to acute laboratory stressors during the ML phase in sleep deprived women. Heart rate (HR), mean arterial pressure (MAP), forearm vascular conductance (FVC), and MSNA were measured in 14 eumenorrheic women (age, 20±1 years) during 10 min supine rest, 5 min mental stress (MS) trial, and 2 min cold pressor test (CPT) trial. Subjects were tested twice after TSD: once during EF phase and once during ML phase (randomized, crossover design). Estradiol (29±2 vs. 63±8pg/ml, p=0.001) and progesterone (1.6±0.2 vs. 4.4±0.7ng/ml, p=0.002) were elevated during the ML phase. Resting supine MAP (75±2 vs. 72±1mmHg, p=0.042) was lower during the ML phase. In contrast, resting supine HR, MSNA, and FVC were not different between EF and ML phases. MAP, HR and FVC reactivity to MS were not statistically different between the EF and ML phases. Similarly, MAP and HR reactivity to CPT were not different between the ovarian phases. Contrary to our original hypothesis, the ML phase was not associated with sympathoexcitation or exaggerated cardiovascular reactivity in sleep deprived premenopausal women. However, our data reveal lower resting blood pressure during the ML phase in sleep deprived women. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: Altered external mechanical loading during spaceflights causes negative effects on muscular and cardiovascular systems. The aim of the study was estimation of the cortical cytoskeleton statement of the skeletal muscle cells and cardiomyocytes. The state of the cortical cytoskeleton in C57BL6J mice soleus, tibialis anterior muscle fibres and left ventricle cardiomyocytes was investigated after 30-day 2g-centrifugation ("2g" group) and within 12 hours after its completion ("2g+12h" group). We used atomic force microscopy for estimating cell's transverse stiffness, western-blotting for measuring protein content, and RT-PCR - for estimating their expression level. The transverse stiffness significantly decreased in cardiomyocytes (by 16%) and increased in skeletal muscles fibres (by 35% for soleus and by 29% for tibialis anterior muscle fibers) in animals of "2g" group (as compared to the control group). For cardiomyocytes we found that in "2g+12h"group alpha-actinin-1 content decreased in the membranous fraction (by 27%) and increased in cytoplasmic fraction (by 28%) of proteins (in comparison with the levels in "2g" group). But for skeletal muscle fibers similar changes were noted for alpha-actinin-4, but not for alpha-actinin-1. In conclusion, we showed that the different isoforms of alpha-actinins dissociate from cortical cytoskeleton under increased/decreased of mechanical load. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: Background: Cardiovascular biomarkers provide independent prognostic information considering mortality and cardiovascular complications. However little is known on possible interactions between these biomarkers. In the present study, we evaluated the influence of BNP on Mid-regional-pro-Adrenomedullin, C-terminal-pro Endothelin-1, Growth differentiation Factor 15, Mid-regional-pro-ANP, Copeptin and Pro-Calcitonin in healthy volunteers. Methods: Ten healthy male subjects (mean age 24 years) received in a randomised placebo controlled single blinded cross over study placebo or 3.0 pmol/kg/min human BNP 32 during a continuous infusion lasting for 4 hours. Effects of BNP on other cardiovascular biomarkers were assessed. Results: BNP did not change concentrations of Mid-regional-pro-Adrenomedullin, Copeptin, C-terminal-pro Endothelin-1, Growth differentiation Factor 15 and Pro-Calcitonin. In contrast Mid-Regional pro Atrial Natriuretic Peptide was significantly decreased during BNP infusion. Conclusion: BNP as well established cardiovascular biomarker did not affect plasma concentrations of other cardiovascular biomarkers in a model of healthy volunteers. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: Rapid onset vasodilation (ROV) following single muscle contractions has been examined in the forearm of humans, but has not yet been characterized in the leg. Given known vascular differences between the arm and leg, we sought to characterize ROV following single muscle contractions in the leg. Sixteen healthy men performed random ordered single contractions at 5, 10, 20, 40, and 60% of their maximum voluntary contraction (MVC) using isometric knee extension made with leg above and below heart level, and compared to single isometric contractions of the forearm (handgrip). Single thigh cuff compressions (300 mmHg) were utilized to estimate the mechanical contribution to leg ROV. Continuous blood flow was determined by duplex-Doppler Ultrasound and blood pressure via finger photoplethysmography (Finometer). Single isometric knee extensor contractions produced intensity-dependent increases in peak leg vascular conductance that were significantly greater than the forearm in both the above and below heart level positions (e.g., above heart level: Leg 20% MVC: +138±28% vs. Arm 20% MVC: +89±17%; P<0.05). Thigh cuff compressions also produced a significant hyperemic response, but these were brief and smaller in magnitude compared to single isometric contractions in the leg. Collectively, these data demonstrate the presence of a rapid and robust vasodilation to single muscle contractions in the leg that is largely independent of mechanical factors, thus, establishing the leg as a viable model to study ROV in humans. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: The cell surface receptor Fn14/TWEAKR was recently reported by our laboratory to be a prominent marker in the resistance exercise (RE) induced Transcriptome. The purpose of the current study was to extend our Transcriptome findings and investigate the gene and protein expression time course of markers in the TWEAK-Fn14 pathway following RE or run exercise (RUN). Vastus Lateralis muscle biopsies were obtained from 6 RE subjects (25±4 y, 1-RM: 99±27 kg) pre and 0h, 1h, 2h, 4h, 8h, 12h, and 24h post RE (3x10 70% 1-RM). Lateral Gastrocnemius biopsies were obtained from 6 RUN subjects (25±4 y, VO2max: 63±8 ml/kg/min) pre, 0h, 1h, 2h, 4h, 8h, 12h, and 24h after a 30-min RUN (75% VO2max). After RE, Fn14 gene and protein expression was induced (p<0.05) and peaked at 8h and 12h, respectively. Downstream markers analyzed showed evidence of TWEAK-Fn14 signaling through the alternative NF-κB pathway after RE. After RUN, Fn14 gene expression was induced (p<0.05) to a much lesser extent and peaked at 24h. Fn14 protein expression was only measurable on a sporadic basis, and there was weak evidence of alternative NF-κB pathway signaling after RUN. TWEAK gene and protein expression were not influenced by either exercise mode. These are the first human data to show a transient activation of the TWEAK-Fn14 axis in the recovery from exercise, and our data suggest the level of activation is exercise mode dependent. Furthermore, our collective data support a myogenic role for TWEAK-Fn14 through the alternative NF-κB pathway in human skeletal muscle. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;
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    ABSTRACT: With the growing interest in adventure travel and the increasing ease and affordability of air, rail and road-based transportation, increasing numbers of individuals are traveling to high altitude. The decline in barometric pressure and ambient oxygen tensions in this environment trigger a series of physiologic responses across organ systems and over a varying time frame that help the individual acclimatize to the low oxygen conditions but occasionally lead to maladaptive responses and one or several forms of acute altitude illness. The goal of this Physiology in Medicine article is to provide information that providers can use when counseling patients who present to primary care or travel medicine clinics seeking advice about how to prevent these problems. After discussing the primary physiologic responses to acute hypoxia from the organ to the molecular level in normal individuals, the review describes the main forms of acute altitude illness -- acute mountain sickness, high altitude cerebral edema and high altitude pulmonary edema - and the basic approaches to their prevention and treatment of these problems, with an emphasis throughout on the physiologic basis for the development of these illnesses and their management. Copyright © 2014, Journal of Applied Physiology.
    Journal of Applied Physiology 12/2014;