A small handheld breathing exercise device, usually used by athletes, helped to reduce breathlessness and improved physical fitness of people recovering from COVID-19, according to research presented at a meeting of the Physiological Society on February 22-23, focussing on long COVID mechanisms, risk factors, and recovery.
Persistent breathlessness is a common post-COVID complaint, and the device offers the potential for a low cost, home-based rehabilitation programme to increase respiratory muscle strength and speed recovery.
The study involved 148 participants recruited through social media and included a few discharged hospital patients. They were randomised into intervention and control groups, and those in the intervention group were each given one of the handheld devices and instructed to breathe into it as deeply as possible for about 20 minutes 3 times a week over 8 weeks.
Compared with the control group, those who undertook the breathing exercises had a 33% reduction in breathlessness, twice the level considered clinically meaningful. In addition, estimated fitness increased by approximately 10% and respiratory strength increased by approximately 36%. The health improvements over the study period were 2-14 times greater for the intervention group compared with the control group. Participants reported feeling less breathless, stronger, fitter, and more able to move around easily, similar to their pre-COVID levels.
The devices used involve breathing against resistance to increase respiratory muscle strength, a technique known as inspiratory muscle training (IMT) and often used by sportspeople. This is the first study of its use in recovering COVID patients, although the team have worked with people with many other types of respiratory conditions, including chronic obstructive pulmonary disease, asthma and cystic fibrosis.
In one small study that they reported last year, significant increases in maximal inspiratory pressure (MIP) were seen both in 10 patients with bronchiectasis (27% increase in MIP) and in 8 healthy individuals undertaking the IMT intervention (a 32% MIP increase) at the same time. Participants also showed increases in sustained MIP (16% and 17%, respectively) and inspiratory duration (36% vs. 30%, respectively). Healthy participants exhibited further improvements in peak expiratory flow and maximal oxygen consumption. IMT also had a positive effect on perceived competency and autonomy, with bronchiectasis patients reporting improved physical ability and motivation, and high adherence.
Studies in Other Conditions Halted in Pandemic
Ironically, studies in other conditions were paused because of COVID measures.
"We were in the process of evaluating the utility of this specific device for both children and adults with cystic fibrosis,”" presenter and lead author Melitta McNarry, professor of sport and exercise sciences at the University of Swansea, told Medscape UK. "However the pandemic has halted that research for the moment."
For COVID-related breathlessness, she explained that: "The key unique features of the device that made it ideal for the intended purpose... included providing the participant with feedback following every breath to show how they had performed, as well as encouraging them to maintain the breath in for as long as possible, and maintaining the resistance throughout that effort rather than just at the outset of the effort.
"Our device also relies on an assessment of maximal capacity prior to every training session, which is particularly important for those with long COVID given the relapsing and remitting nature of the disease, as it ensures that they never undertake exercise above their capacity for that day."
The team’s presentation concluded: "It’s vital we develop safe and effective home-based rehabilitation methods to help people recover quickly and fully from COVID-19. Breathing muscle training enabled people to return to activities they had been unable to do for weeks or months, providing physical and mental health benefits.
"The unsupervised nature of this method and the relatively low cost of the devices could be used to ease the strain on the NHS."