Maximal Respiratory Pressures

IJCS

Brief Communication

Increased Maximal Expiratory Pressure, Abdominal and Thoracic Respiratory Expansibility in Healthy Yoga Practitioners Compared to Healthy Sedentary Individuals

Cláudia Fetter et al. Liliane Appratto de Souza Daniela Ravizzoni Dartora Andressa Schein … Bruna Eibel Karina Casali Maria Cláudia Irigoyen

Abstract

Background

Increasing thoracic expansion is effective at reducing blood pressure in hypertensive subjects. Yoga prescribes many respiratory techniques with a growing number of practitioners. However, very little is known whether sedentary or yoga practitioners show measurable differences in their respiratory patterns.

Objective

This study aims to demonstrate differences between healthy sedentary individuals and healthy yoga practitioners regarding maximal respiratory pressures and thoracic and abdominal respiratory expansibility.

Methods

Maximal inspiratory and expiratory pressures (MIP and MEP, respectively) were evaluated by manovacuometry, while respiratory expansion was assessed by the cirtometry of abdominal (CA), thoracic xiphoidal (CTX), and thoracic axillary (CTA) circumferences at rest (end expiratory moment) and at full inspiration in healthy sedentary individuals (SED) and yoga practitioners (YOGA). A delta derived from rest and full inspiration measures (ΔCA, ΔCTX, and ΔCTA, respectively), followed by a percentage of each item (ΔCA/CA, ΔCTX/CTX, and ΔCTA/CTA) was then calculated. Groups were compared by means of an unpaired Student’s t-test, with a significance level p < 0.05.

Results

All respiratory expansion measures were significantly higher in in the YOGA group. A significantly higher MEP (cmH₂O) was also detected in yoga practitioners: SED 89.3 ± 19.3 and YOGA 114.7 ± 24.8 ( p = 0.007), along with decreased heart rate at rest (bpm): SED 84±6 and YOGA 74±15 ( p = 0.001).

Conclusions

Yoga practitioners have shown greater thoracic and abdominal expansion and increased MEP, when compared to healthy sedentary individuals, as well as significantly lower heart rates at rest and body mass index (BMI). However, whether or not these findings are related to respiratory patterns is uncertain.

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ABC

Editorial

Inspiratory Muscle Training at Different Intensities in Heart Failure: Are There Differences in Central Hemodynamic Changes?

Lucas Helal et al. Filipe Ferrari

Inspiratory muscle training in heart failure

There is robust evidence suggesting that the weakness of inspiratory muscles is one of the main factors that lead to low exercise tolerance in patients with HF.^, In fact, randomized clinical trials have shown several benefits of IMT in patients with this syndrome, namely: significant improvement in oxygen uptake efficiency, functional capacity and quality of life scores. These results were confirmed by meta-analyses, such as that carried out by Smart et al. When compared to the control group, patients undergoing IMT achieved an important improvement in maximum oxygen consumption (VO₂max): 1.83 mL.kg^-1.min^-1(95%CI, 1.33 for 2.32 mL.kg^-1.min^-1, p <0.00001), as well as in the 6-minute walking test: 34.35 m (95%CI, 22.45 to 46.24 m, p <0.00001). In turn, inspiratory muscle strength seems to have a significant correlation with VO₂max, which is an independent predictor of survival in individuals with HF. IMT should therefore be an integral part of these patients’ care whenever possible.

In this issue of the Arquivos Brasileiros de Cardiologia , a randomized, placebo-controlled trial evaluated the implications of an acute session of different intensities of IMT on the central hemodynamic response (CHR) of individuals with HF, using a non-invasive monitoring method. For this purpose, 20 patients with reduced ejection fraction (37.2% ± 6.3%), a mean age of 65 years, and the vast majority in New York Heart Association (NYHA) functional class II were included in the study. The IMT protocol consisted of 3 sessions lasting 15 minutes each. All participants underwent the training with an intensity of 30% and 60% of maximum inspiratory pressure (MIP), in addition to sham intervention (placebo), with a 1-hour washout between them. It was observed that CHR behaved in a heterogeneous way between intensities. For instance, there was an increase in heart rate with intensities of 30% and 60% of MIP (64 ± 15 to 69 ± 15 beats per minute; and 67 ± 14 to 73 ± 14 beats per minute, respectively). Regarding stroke volume, there was a tendency to decrease with a 30% load of MIP (73 ± 26 mL to 64 ± 20 mL). The cardiac output increased only in the group with the highest intensity (4.6 ± 1.5 L / min to 5.3 ± 1.7 L / min), a behavior that was similar in relation to the systolic blood pressure response. In fact, the increase in cardiac output observed at the highest applied intensity can be partially explained by the increase in heart rate in this group. These findings should not be ignored, since patients with HF tend to have impaired blood flow to the active muscles, secondary to reductions in cardiac output and peripheral vasodilator capacity. These changes are harmful, causing important intolerance to effort, being associated with reduced vasodilator capacity and increased sympathetic stimulation, common in these individuals.

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