R-R interval variability (RR variability) is increasingly being used as an index of autonomic activity. High-frequency (HF) power reflects vagal modulation of the sinus node. Since vagal modulation occurs at the respiratory frequency, some investigators have suggested that HF power cannot be interpreted unless the breathing rate is controlled. We hypothesized that HF power during spontaneous br...

Very few quantitative observations have been reported on the effect of rate of breathing on the voluntary maximum breathing capacity (M.B.C.). Proctor and Hardy (1949) found that the M.B.C. was achieved at a rate of 30 respirations per minute (R.P.M.). At higher rates of breathing the ventilatory capacity was diminished. These observations are contrary to the findings of other investigators who...

This study aims to assess regional ventilation, nonlinearity, and hysteresis of human lungs during dynamic breathing via image registration of four-dimensional computed tomography (4D-CT) scans. Six healthy adult humans were studied by spiral multidetector-row CT during controlled tidal breathing as well as during total lung capacity and functional residual capacity breath holds. Static images ...

BACKGROUND Floor dust is commonly used for microbial determinations in epidemiological studies to estimate early-life indoor microbial exposures. Resuspension of floor dust and its impact on infant microbial exposure is, however, little explored. The aim of our study was to investigate how floor dust resuspension induced by an infant's crawling motion and an adult walking affects infant inhalat...

Emerging evidence has suggested that with minimal prerequisite training, slow deep breathing around 0.10 Hz can acutely enhance cardiovagal baroreflex sensitivity (BRS) in humans. Such reports have led to the speculation that behavioral interventions designed to reduce breathing frequency may serve a therapeutic role in ameliorating depressed baroreflex function in conditions such as chronic he...

mouth breathing might not always result in hypoxia, but can contribute to it. the aim of the present study was to determine the effect of mouth breathing on hypoxia. based on a pilot study, 323 patients with mouth breathing were selected. assessment of mouth breathing was based on clinical examination and questionnaires filled out by patients and their companions. the patients were also examine...

Background: Cancer can cause undesired side effects that significantly alter patients’ perceived stress and mindfulness. The integration of nonpharmacologic, complementary health interventions, such as mindful breathing, is potentially useful in reducing promoting the well-being patients during treatment. Objectives: This study examined a five-minute breathing practice performed three times per...

There has been an increasing demand on the part of scuba diving instructors and other diving authorities for a re-evaluation of emergency ascent procedures. Many diving medical authorities challenge the inclusion of open water free ascent or emergency controlled swimming ascent training in basic and advanced sport diving courses. In essence, they feel that-the potential risk of lung barotrauma ...

Evidence derived from spontaneous measures of cardiovagal baroreflex sensitivity (BRS) suggests that slow breathing at 6 breaths/min augments BRS. However, increases in BRS associated with slow breathing may simply reflect the frequency-dependent nature of the baroreflex rather than the modulation of baroreflex function by changes in breathing rate per se. To test this hypothesis we employed a ...