Dennis Jensen

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Progressive activity-related dyspnea dominates the clinical presentation of patients afflicted by chronic obstructive and restrictive lung diseases. This symptom invariably leads to activity limitation, global skeletal muscle deconditioning and an impoverished quality of life. The effective management of exertional dyspnea remains an elusive goal but our(More)
This study examined the effects of menstrual cycle phase on ventilatory control. Fourteen eumenorrheic women were studied in the early follicular (FP; 1-6 days) and mid-luteal (LP; 20-24 days) phase of the menstrual cycle. Blood for the determination of arterial PCO(2) (PaCO(2)) , plasma strong ion difference ([SID]), progesterone ([P(4)]), and(More)
The purpose of this study was to evaluate the physiological basis for sex-differences in exercise-induced dyspnea in patients with mild COPD. We compared operating lung volumes, breathing pattern and dyspnea during incremental cycling in 32 men (FEV(1)=86±10% predicted) and women (FEV(1)=86±12% predicted) with mild COPD and 32 age-matched controls. There(More)
This study examined the role of pregnancy-induced changes in wakefulness (or non-chemoreflex) and central chemoreflex drives to breathe, acid-base balance and female sex hormones in the hyperventilation of human pregnancy. Thirty-five healthy women were studied in the third trimester (TM(3); 36.3+/-1.0 weeks gestation; mean+/-S.D.) and again 20.2+/-7.8(More)
We examined the effects of dead space loading (DSL) on ventilation (V˙E), neural respiratory drive (EMGdi%max, diaphragm EMG expressed as a % of maximal EMGdi), contractile respiratory muscle effort (Pes,tidal%P(Imax), tidal esophageal pressure swing expressed as a % of maximal inspiratory Pes) and exertional dyspnea intensity ratings in 11 healthy adults(More)
To examine the effect of age-related respiratory function impairment on exertional dyspnea, we compared ventilatory and perceptual responses to incremental exercise under control (CTRL) and added dead space (DS) loading conditions in healthy fit older (55-79 years) and younger (20-39 years) men. Older individuals had higher ventilatory equivalents for CO2(More)
The healthy human respiratory system has impressive ventilatory reserve and can easily meet the demands placed upon it by strenuous exercise. Several acute physiological adaptations during exercise ensure harmonious neuromechanical coupling of the respiratory system, which allow healthy humans to reach high levels of ventilation without perceiving undue(More)
This study examined the effects of human pregnancy and advancing gestation on the intensity of respiratory discomfort (dyspnea) during cycle exercise. Fourteen pregnant women (PG) performed a progressive cycle ergometer exercise test involving 20 W/min increases in work rate to symptom limitation and/or a heart rate of 170-175 beats/min at 19.7+/-1.2 weeks(More)
BACKGROUND The aim of this study was to evaluate the responsiveness of the 3-minute constant rate step test (3-MST) to detect the relief of exertional dyspnea (respiratory discomfort) after acute bronchodilation in COPD patients. PATIENTS AND METHODS A total of 40 patients with moderate-to-severe COPD (mean forced expiratory volume in 1 second: 45.7(More)
This randomized, double-blind, crossover study examined the effects of a clothing ensemble made of a synthetic fabric promoted as having superior cooling properties (COOL) on exercise performance and its physiological and perceptual determinants during cycle exercise in ambient laboratory conditions that mimic environmental conditions of indoor(More)