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Efficacy and tolerability of yoga breathing in patients with chronic obstructive pulmonary disease: a pilot study

PURPOSE: Yoga-derived breathing has been reported to improve gas exchange in patients with chronic heart failure and in participants exposed to high-altitude hypoxia. We investigated the tolerability and effect of yoga breathing on ventilatory pattern and oxygenation in patients with chronic obstructive pulmonary disease (COPD). METHODS: Patients with COPD (N = 11, 3 women) without previous yoga practice and taking only short-acting ?2-adrenergic blocking drugs were enrolled. Ventilatory pattern and oxygen saturation were monitored by means of inductive plethysmography during 30-minute spontaneous breathing at rest (sb) and during a 30-minute yoga lesson (y). During the yoga lesson, the patients were requested to mobilize in sequence the diaphragm, lower chest, and upper chest adopting a slower and deeper breathing. We evaluated oxygen saturation (SaO2%), tidal volume (VT), minute ventilation (E), respiratory rate (i>f), inspiratory time, total breath time, fractional inspiratory time, an index of thoracoabdominal coordination, and an index of rapid shallow breathing. Changes in dyspnea during the yoga lesson were assessed with the Borg scale. RESULTS: During the yoga lesson, data showed the adoption of a deeper and slower breathing pattern (VTsb L 0.54[0.04], VTy L 0.74[0.08], P = .01; i>fsb 20.8[1.3], i>fy 13.8[0.2], P = .001) and a significant improvement in SaO2% with no change in E (SaO2%sb 91.5%[1.13], SaO2%y 93.5%[0.99], P = .02; Esb L/min 11.2[1.1], Ey L/min 10.2[0.9]). All the participants reported to be comfortable during the yoga lesson, with no increase in dyspnea index. CONCLUSION: We conclude that short-term training in yoga is well tolerated and induces favorable respiratory changes in patients with COPD.

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Respiratory function at different altitudes

For the evaluation of a respiratory test at high altitude, several factors must be taken into account: the decreased barometric pressure, the decreased density of air and the degree of acclimatization which is related to the altitude and to the length of exposure. Several studies have shown a reduction in forced vital capacity (FVC) at high altitude and using simulated conditions, mainly related to an increase in pulmonary blood volume and development of interstitial edema. To assess the daily spirometric patterns during ascending to high altitudes we studied 17 healthy subjects at both Capanna Regina Margherita on the Italian Alps (4,559 m) and the Pyramid Laboratory in Nepal (5,050 m). Respiratory function tests were performed every day. Peak expiratory flow values significantly increased. The mean percent increase was 15% at 3,200 and 3,600 m and 26% at 4,559 m. FVC and MEF25 values showed a significant decrease (p < 0.005) during the first days above 3,500 m and improved only after several days spent above this altitude. For each subject the maximal reductions in FVC and maximal expiratory flow (MEF) at 25% of FVC however were found on different days. In our opinion, these data support the hypothesis that at high altitude the respiratory function can be affected by the presence of an increased pulmonary blood volume and/or the development of interstitial edema. The observed changes in forced expiration curves at high altitude seem to reflect the degree of acclimatization that is related to the individual susceptibility, to the altitude reached and to the duration of the exposure. These changes are transient and resolve after returning to sea level.

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Hypoxic ventilatory response in successful extreme altitude climbers

A very high ventilatory response to hypoxia is believed necessary to reach extreme altitude without oxygen. Alternatively, the excessive ventilation could be counterproductive by exhausting the ventilatory reserve early on. To test these alternatives, 11 elite climbers (2004 Everest-K2 Italian Expedition) were evaluated as follows: 1) at sea level, and 2) at 5,200?m, after 15 days of acclimatisation at altitude. Resting oxygen saturation, minute ventilation, breathing rate, hypoxic ventilatory response, maximal voluntary ventilation, ventilatory reserve (at oxygen saturation?=?70%) and two indices of ventilatory efficiency were measured. Everest and K2 summits were reached 29 and 61 days, respectively, after the last measurement. Five climbers summited without oxygen, the other six did not, or succeeded with oxygen (two climbers). At sea level, all data were similar. At 5,200?m, the five summiters without oxygen showed lower resting minute ventilation, breathing rate and ventilatory response to hypoxia, and higher ventilatory reserve and ventilatory efficiency, compared to the other climbers. Thus, the more successful climbers had smaller responses to hypoxia during acclimatisation to 5,200?m, but, as a result, had greater available reserve for the summit. A less sensitive hypoxic response and a greater ventilatory efficiency might increase ventilatory reserve and allow sustainable ventilation in the extreme hypoxia at the summit.

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High-altitude exposure reduces inspiratory muscle strength.

It was the aim of the study to assess the maximal pressure generated by the inspiratory muscles (MIP) during exposure to different levels of altitude (i.e., hypobaric hypoxia). Eight lowlanders (2 females and 6 males), aged 27 - 46 years, participated in the study. After being evaluated at sea level, the subjects spent seven days at altitudes of more than 3000 metres. On the first day, they rode in a cable car from 1200 to 3200 metres and performed the first test after 45 - 60 minutes rest; they then walked for two hours to a mountain refuge at 3600 metres, where they spent three nights (days 2 - 3); on day 4, they walked for four hours over a glacier to reach Capanna Regina Margherita (4559 m), where they spent days 5 - 7. MIP, flow-volume curve and SpO (2) % were measured at each altitude, and acute mountain sickness (Lake Louise score) was recorded. Increasing altitude led to a significant decrease in resting SpO (2) % (from 98 % to 80 %) and MIP (from 134 to 111 cmH (2)O) (baseline to day 4: p < 0.05); there was an improvement in SpO (2) % and a slight increase in MIP during the subsequent days at the same altitude. Expiratory (but not inspiratory) flows increased, and forced vital capacity and FEF (75) decreased at higher altitudes. We conclude that exposure to high altitude hypoxia reduces the strength of the respiratory muscles, as demonstrated by the reduction in MIP and the lack of an increase in peak inspiratory flows. This reduction is more marked during the first days of exposure to the same altitude, and tends to recover during the acclimatisation process.

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Respiratory diseases and high altitude

The aim of this paper is to review how preexisting pulmonary diseases can be affected by altitude exposure. Obstructive (asthma and chronic obstructive pulmonary disease or COPD) and restrictive (interstitial pulmonary fibrosis), as well as pulmonary vascular diseases, will be considered, and the goal will be to provide insight and tools to clinicians to optimize the medical condition and thus the life-style of these patients. The underlying pathophysiologies and the effect of hypobaric hypoxia on these diseases will be reviewed such that techniques to assess patients will be appropriate. Therapeutic interventions, including the use of supplemental oxygen, in light of the underlying pathologic processes, will also be discussed.

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Airway Responses to Methacholine and exercise at High Altitude in Healthy Lowlanders.

Peribronchial edema has been proposed as a mechanism enhancing airway responses to constrictor stimuli. Acute exposure to altitude in nonacclimatized lowlanders leads to subclinical interstitial pulmonary edema that lasts for several days after ascent, as suggested by changes in lung mechanics. We, therefore, investigated whether changes in lung mechanics consistent with fluid accumulation at high altitude within the lungs are associated with changes in airway responses to methacholine or exercise. Fourteen healthy subjects were studied at 4,559 and at 120 m above sea level. At high altitude, both static and dynamic lung compliances and respiratory reactance at 5 Hz significantly decreased, suggestive of interstitial pulmonary edema. Resting minute ventilation significantly increased by ?30%. Compared with sea level, inhalation of methacholine at high altitude caused a similar reduction of partial forced expiratory flow but less reduction of maximal forced expiratory flow, less increments of pulmonary resistance and respiratory resistance at 5 Hz, and similar effects of deep breath on pulmonary and respiratory resistance. During maximal incremental exercise at high altitude, partial forced expiratory flow gradually increased with the increase in minute ventilation similarly to sea level but both achieved higher values at peak exercise. In conclusion, airway responsiveness to methacholine at high altitude is well preserved despite the occurrence of interstitial pulmonary edema. We suggest that this may be the result of the increase in resting minute ventilation opposing the effects and/or the development of airway smooth muscle force, reduced gas density, and well preserved airway-to-parenchyma interdependence.

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Relationship between individual ventilatory response and acute renal water excretion at high altitude

We tested the hypothesis that the individual ventilatory adaptation to high altitude (HA, 5050 m) may influence renal water excretion in response to water loading. In 8 healthy humans (33+/-4 S.D. years) we studied, at sea level (SL) and at HA, resting ventilation (VE), arterial oxygen saturation (SpO2), urinary output after water loading (WL, 20 mL/kg), and total body water (TBW). Ventilatory response to HA was defined as the difference in resting VE over SpO2 (DeltaVE/DeltaSpO2) from SL to HA. At HA, a significant increase in urinary volume after the first hour from WL (%WLt0-60) was observed. Significant correlations were found between DeltaVE/DeltaSpO2 versus %WLt0-60 at HA and versus changes in TBW, from SL to HA. In conclusion, in healthy subjects the ventilatory response to HA influences water balance and correlates with kidney response to WL. A higher ventilatory response at HA, allowing a more efficient water renal handling, is likely to be a protective mechanisms from altitude illness.

Metadata

Respiratory function at different altitudes

For the evaluation of a respiratory test at high altitude, several factors must be taken into account: the decreased barometric pressure, the decreased density of air and the degree of acclimatization which is related to the altitude and to the length of exposure. Several studies have shown a reduction in forced vital capacity (FVC) at high altitude and using simulated conditions, mainly related to an increase in pulmonary blood volume and development of interstitial edema. To assess the daily spirometric patterns during ascending to high altitudes we studied 17 healthy subjects at both Capanna Regina Margherita on the Italian Alps (4,559 m) and the Pyramid Laboratory in Nepal (5,050 m). Respiratory function tests were performed every day. Peak expiratory flow values significantly increased. The mean percent increase was 15% at 3,200 and 3,600 m and 26% at 4,559 m. FVC and MEF25 values showed a significant decrease (p < 0.005) during the first days above 3,500 m and improved only after several days spent above this altitude. For each subject the maximal reductions in FVC and maximal expiratory flow (MEF) at 25% of FVC however were found on different days. In our opinion, these data support the hypothesis that at high altitude the respiratory function can be affected by the presence of an increased pulmonary blood volume and/or the development of interstitial edema. The observed changes in forced expiration curves at high altitude seem to reflect the degree of acclimatization that is related to the individual susceptibility, to the altitude reached and to the duration of the exposure. These changes are transient and resolve after returning to sea level.

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The Lung at high altitude: between physiology and pathology in Problems of high altitude medicine and biology

The lungs play a pivotal role in adaptation to high altitude. The increase in ventilation and the rise in pulmonary artery pressure are the first features of lung response to hypoxic exposure. At high altitude the lungs can also be affected by high-altitude pulmonary oedema, a severe form of acute mountain sickness. In healthy subjects the ascent to high altitude is also associated with alterations in lung function, which have been in part interpreted as an effect of extra vascular lung fluid accumulation. The patterns of respiratory function changes at high altitude are discussed, taking into account the body fluid movement and the increase in endothelial permeability induced by hypoxic exposure. As the problem of “respiratory” patients at high altitude is very important, a short summary of the guidelines for altitude exposure of asthmatic and COPD patients is reported at the end of the chapter.

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Efficacy and tolerability of yoga breathing in patients with chronic obstructive pulmonary disease: a pilot study

Yoga-derived breathing has been reported to improve gas exchange in patients with chronic heart failure and in participants exposed to high-altitude hypoxia. We investigated the tolerability and effect of yoga breathing on ventilatory pattern and oxygenation in patients with chronic obstructive pulmonary disease (COPD). METHODS: Patients with COPD (N = 11, 3 women) without previous yoga practice and taking only short-acting ß2-adrenergic blocking drugs were enrolled. Ventilatory pattern and oxygen saturation were monitored by means of inductive plethysmography during 30-minute spontaneous breathing at rest (sb) and during a 30-minute yoga lesson (y). During the yoga lesson, the patients were requested to mobilize in sequence the diaphragm, lower chest, and upper chest adopting a slower and deeper breathing. We evaluated oxygen saturation (SaO2%), tidal volume (VT), minute ventilation (E), respiratory rate (i>f), inspiratory time, total breath time, fractional inspiratory time, an index of thoracoabdominal coordination, and an index of rapid shallow breathing. Changes in dyspnea during the yoga lesson were assessed with the Borg scale.

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