Resistance-breathing training can lower blood pressure as much as some medicines


A team of researchers with members from the University of Colorado, the University of Arizona and Alma College, all in the U.S., has found that resistance-breathing training can lower blood pressure as much as some medicines and/or exercises. The study is published in the Journal of Applied Physiology.

Hypertension, also known as chronic high blood pressure, can lead to a wide variety of health problems, from loss of vision to strokes and heart attacks. For that reason, doctors take it seriously. Typically, patients are directed to modify their diet and to exercise more. If that does not fix the problem, medications are prescribed. In this new effort, the researchers looked into a new type of therapy to reduce blood pressure levels—resistance-breathing training.

Resistance-breathing training involves breathing in and out of a small device, called, quite naturally, a POWERbreathe, every day for several minutes. The device forces the patient to use their breathing muscles to push and pull air through it, making them stronger. And that, the researchers found, also reduces blood pressure. The device has been in use for several years as a means to assist athletes, singers and people with weak lung muscles.

Several groups of healthy volunteers practiced the training for a few minutes every day for six weeks. Each was breathed in and out with the device 30 times each session. Each of the volunteers had their blood pressure measured before and after the training.

The researchers found a sustained average drop of 9 mmHg in systolic blood pressure (the top number in blood pressure readings)—normal pressure is defined as 120/80. They describe the change as significant, as much as some patients see with medication.

They also note that it is similar to changes in many patients who begin an aerobic exercise regimen, such as walking, cycling or running. They suggest such training could be used by patients of all ages who are unable to exercise to lower their blood pressure.

The main function of the respiratory system is to maintain alveolar ventilation (oxygen-(O2) intake) in proportion to the metabolic needs of the organism, which increase during physical activity (PA) [1]. Also, carbon dioxide (CO2) exhalation is the main driver of ventilation to prevent arterial blood carbon dioxide pressure (PaCO2) from increasing and arterial blood oxygen pressure (PaO2) from decreasing [2].

During an intense and prolonged PA, the muscular endurance of the respiratory tracts decreases as a response to an increase in the respiratory muscle work and dyspnoea [3].

This fact induces fatigue in the respiratory muscles (RM) and reduces the respiratory function, resulting in a lessening of respiratory endurance [4]. This reduced respiratory activity could be connected to the activation of the metabolic reflex mechanism of the respiratory muscles (RMRM) “metaboreflex”.

The RMRM is initiated by the fatigue of the respiratory muscles, which, through the afferent pathways III and IV, reaches the supraspinal level, causing a sympathetic vasoconstrictor response in the locomotor peripheral musculature which intensifies the fatigue of the active muscles and, in addition, increases the perception of effort, contributing to an endurance limitation linked to intense aerobic exercise [5].

Furthermore, the respiratory fatigue prevents the RM from reaching a suitable pleural pressure, this is an endurance limiting factor especially in disciplines which require aerobic resistance [6]. Other limiting factors of high-intensity physical endurance are pulmonary mechanics and pulmonary diffusion themselves [3].

Elite athletes of diverse modalities tend to combine ergogenic strategies in the hopes of improving their physiological responses and their competitive endurance; however, scientific evidence is occasionally limited [7]. One of the strategies employed is inspiratory muscle training (IMT), whose purpose is to enhance exercise tolerance [8].

IMT has been used to minimize and/or delay respiratory fatigue, the RMRM and the blood lactate concentration (LA) [9]. In this way, IMT could be considered a training method with a potential ergogenic effect to improve athletic performance [10]. Additionally, it has been suggested that other physiological mechanisms could explain the ergogenic effect of the IMT: diaphragm hypertrophy, an increase of the sanguine flow to locomotor muscles, a diminution in the subjective blood flow, reduction of fatigue, decreased dyspnoea, an increment in the efficiency and respiratory endurance, an alteration in the composition of muscular fibres to type I and augmentation of fibres type II in intercostal muscles, optimization of neuro-motor control in respiratory muscles maintaining the production of pressure with a minor motor impulse and a higher economization of the respiratory muscles [11]. Moreover, IMT is employed as a treatment for patients with respiratory condition—such as asthma, dyspnoea, and chronic obstructive pulmonary disease—with a better standard of living of the patients as a result [12,13].

IMT devices, which perform sectorized training of the respiratory muscles, can be divided into three categories: of resistive charge, of voluntary isocapnic hyperpnea, and threshold devices [14]. PowerBreathe® (PwB) [PowerBreathe International Ltd. Southam, Warwickshire; England UK] is a threshold device that allows air flow during an inspiration only after reaching a certain inspiratory pressure, which is adjustable through the tension of a spring in accordance with the maximal inspiratory pressure (MIP) of a patient.

Once this pressure is surpassed and the valve is opened, the lineal resistance to the flow increment must be inappreciable [15]. The PwB device enables higher charges between 186 and 274 centimetres of water (cmH2O) pressure to be generated by the lungs due to the force of the inspiratory muscles [3].

The inclusion of new elements in PA routines and/or training routines has recently been carried out by both professional and recreational athletes, with the aim of establishing adjustments that would turn into a differential element in their performance [3]. Nevertheless, the results are contradictory, because while IMT has proved to be effective in team sports [4,9,16], cycling [11,17] and runners [18,19], in other studies its efficiency has not been proved [7,20].

Discrepancies could be a result of the methodology (intensity and/or duration of the exercises), the design of the studies and the athletic expertise of the individual employing IMT. Likewise, it is important to consider the kind of improvements attainable in relation to physical endurance.

Considering these circumstances, we decided to execute a systematic revision of these practices to critically evaluate the effects of IMT on respiratory parameters and athletic performance. A PwB device was employed on people who practice diverse types of physical activities. This study describes the magnitude of the inspiratory resistance, the frequency, and the duration of the IMT to establish an optimal programme which will allow improvements in respiratory and athletic endurance.

reference link :

reference link : More information: Daniel H. Craighead et al, A multi-trial, retrospective analysis of the antihypertensive effects of high-resistance, low-volume inspiratory muscle strength training, Journal of Applied Physiology (2022). DOI: 10.1152/japplphysiol.00425.2022


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