How can inspiratory muscle training help with symptoms of reflux?  It has to do with the mechanisms behind gastroesophageal reflux disease (or GERD). GERD is caused by the upward movement of gastric contents from the stomach into the esophagus.  This happens when the sphincter between the stomach and the esophagus (meant to be a one-way door) loses some of it's strength and function.  The result is that stomach contents end up flowing backwards into the esophagus (the pipe that food travels down into the stomach after we swallow).  Symptoms of GERD can be:

• heartburn - burning type pain in the chest area
• feeling of something in the throat
• throat clearing, coughing
• hoarse voice
• shortness of breath
• interrupted sleep

The diagram below shows how the the esophagus passes through the diaphragm and you can even see the muscle fibres of the diaphragm supporting the sphincter.  So it does makes sense that if the diaphragm isn't functioning well, then the sphincter function may also be reduced.  In fact, studies have indicated that individuals with GERD have reduced diaphragm function and altered breathing patterns.  

GERD can be difficult to treat and should include a an approach that includes lifestyle changes (diet, weight loss) and may include medications.  But more recent evidence has shown that strengthening the diaphragm can help.  A few studies have shown that participants with GERD who performed inspiratory muscle training for 4-8 weeks, had reduced symptoms of GERD.  Researchers theorize that IMT helps to improve the function of the lower esophageal sphincter.  For the more recent study abstract click here.  

As we continue on with our series on inspiratory muscle training, we are going to talk about how training your breathing muscles can improve your balance.  Yes, that's right, I said balance.  I know you must be wondering how breathing muscles affect balance, so let's start with a little talk about one of the other functions of the diaphragm:  postural control.
Back in 2000, researchers discovered that the diaphragm would contract during movements that affected the trunk, that were not related to breathing.  This contraction they discovered, increased the pressure within the abdomen and therefore caused increased stiffness (or stability) of the trunk.  Since that time, numerous studies have looked at the role of the diaphragm in postural stability and some very interesting results have occurred.
One study found that fatiguing the diaphragm changed the way a person responds to balance challenges.  Normally, when we are faced with unstable surfaces (standing on soft ground, walking on a suspension bridge), the muscles in our back along the spine will contract to keep us upright and steady.  But if you fatigue your breathing muscles, researchers found that the back muscles can't do their job properly and then the muscles in the ankle are used more, which actually leads to less stability (you sway more).  This is significant because in some respiratory diseases (and in aging) the respiratory muscles can become weakened.  This could impact balance and lead to an increase in falls among those groups.
Which leads to the next study, where researchers then looked at the effects of 8 weeks of inspiratory muscle training on a group of otherwise health older adults. The results were surprising. They found that performing IMT for 8 weeks not only improved respiratory muscle function, but it also improved balance!  Falls are a major health concern for our older population, so these results are promising.
So again, another seemingly far reaching effect of training your breathing muscles.  This isn't anything wild and far-fetched though.  It's using simple strength training principles on a muscle we previously hadn't really thought of as benefiting from getting stronger.  Because the diaphragm has such an influence over a number of systems (respiratory, muscular, gastrointestinal, cardiac) then we can certainly draw some conclusions as to the benefits of having it function as best as it possibly can!
Stay tuned as we explore a bit more of the influence on your gut function in our next segment!

There is increasing evidence about the benefits of inspiratory muscle training on overall health.  A number of studies have looked at IMT to help with sleep apnea, blood pressure, reflux disease, cardiovascular fitness, cognitive function and balance. 

A very exciting study to come out of the University of Colorado had participants do 6 weeks of high intensity IMT - a few minutes per day of breathing into an inspiratory muscle trainer.  While they were initially looking at the effects of IMT on obstructive sleep apnea, they found that participants had reductions in blood pressure and improvements in cognitive function.  This has fuelled a more in-depth project to look at the effects of IMT on blood pressure.   You can read more on this study here.

Early on in the Covid19 pandemic, Cardiorespiratory Physical Therapy Specialist Rich Severin co-authored a paper looking at the role of respiratory muscle weakness in poor clinical outcomes of respiratory infection.  He noted that reduced respiratory muscle strength was common in individuals with poor health and in particular, obesity, and this weakness may lead to increased medical intervention requirements in the wake of respiratory infection.  Thea authors suggested that "in patients identified as having respiratory muscle impairments, respiratory muscle training may prove valuable in mitigating the health impact of future pandemics."  You can read his study here.

There is also an increasing amount of studies looking at the benefits of IMT to help manage gastro-esophageal reflux disease (acid reflux) one of the most common diseases.  It seems that improving diaphragm function also improves the function of the sphincter between the stomach and esophagus, thus reducing reflux.  Click here for an abstract of a recent study on IMT and reflux.

Why are we seeing these benefits of training the respiratory muscles?  A lot of it comes down to the function of the diaphragm, which extends beyond just breathing.  It has roles in:

• gastrointestinal function (stopping the contents of stomach from refluxing)
• acting as a lymphatic pump and encouraging venous return
• trunk stability and posture
• influencing the central nervous system

Given it's numerous roles then, it is not a stretch to see that improved strength and function of this muscle can have far reaching effects - specifically that it can make changes to systems that are seeming unrelated to breathing. And again, IMT is cost-effective with devices costing around $100 and lasting for many years with proper care.  It is easy to do - simply 30 breaths up to twice a day can yield measurable benefits.
Stay tuned for our next blog looking at the effect of IMT on balance!

I think the best place to start our journey into Inspiratory Muscle Training (IMT) is by taking a look at perhaps the most obvious place where training your breathing muscles may have a benefit - lung disease.
  People with lung disease like asthma, COPD and fibrosis generally have an increased awareness about their breathing.  The processes affecting their lung function can make breathing harder for any given activity, which means they are exposed to sensations of breathlessness more frequently.  When we perceive (or even anticipate!) the need to breathe harder - like with activity - we may shift breathing patterns to use more secondary muscles (see previous post).  This type of pattern is often inefficient and not sustainable for long periods.  The secondary muscles are quite greedy  - they use lots of energy to work - and can therefore increase the work of breathing (meaning they make breathing feel even harder).
When muscles used for breathing start to fatigue, they will trigger something called the metaboreflex, and blood that would normally flow to your muscles in your arms and legs, is redirected to the muscles used for breathing.  This is because no matter what you are doing - breathing always wins!  
So the situation looks like this:  you start to feel breathless, so you breathe harder.  The harder you breathe, the more energy your breathing muscles need.  The more they need, the less energy flows to your leg muscles.  Now you not only feel breathless, but your legs feel heavy too and you have to stop doing an activity.  
This actually happens to everybody eventually once a certain level of effort is reached- in athletes in happens much, much later into activity.  But for people with severe lung disease, this can happen just from walking up the stairs.  This can then lead to a vicious cycle of inactivity - you fee breathless when you move, so you move less, which makes you more breathless when you do try to move.
In an effort to help people with lung disease move more and reduce sensations of breathlessness, research has focused on the effects of strengthening the breathing muscles, in an effort to delay the metaboreflex.  And the results are promising.  When the respiratory muscles are strengthened, people have reported less breathlessness and improved tolerance to activity (ie they can walk farther).  Although IMT make no changes to lung function, it can improve quality of life.  IMT is easy to use (takes a few minutes a day to perform) and is cost effective and can be a great add-on to managing lung disease!

Inspiratory muscle training, or IMT, is simply a form of strength training for your breathing muscles that help you breathe in.  The main inspiratory (inhale) muscles are the diaphragm and intercostals (rib muscles).  These muscles do the lion's share of the work of breathing at rest.  When we are more active, secondary muscles are called upon to help increase the volume of the lungs by expanding the ribcage.   These muscles are in the neck, chest, shoulders and back - there are lots of helper muscles for breathing when we are active!
The muscles we use for breathing are just like any other muscle in the body and can weaken due to illness, injury, aging or disuse.  Well, it's not like we intentionally not use our breathing muscles, but sometimes when we rely more on our secondary muscles of breathing (those ones in the neck/chest/shoulders), then it can lead to underuse of the diaphragm.  I find that people with asthma, allergies and anxiety tend to use these helper muscles more than their diaphragm.  This in turn can lead to premature shortness of breath with activity, and sometimes even unexplained breathlessness at rest.
Anyway, just like our other muscles, the breathing muscles can also benefit from strength training.  Except for that it is hard to simply lift a weight with your diaphragm.  And although general cardiovascular exercise - like walking, running or riding a bike - does improve your breathing, it sometimes isn't specific enough to address the muscle weakness of the breathing muscles.  Often, when the muscles are weak, they will limit how much you can push yourself in exercise.
So researchers began to look at what happens when you specifically strengthen your breathing muscles.  By creating a device that adds resistance when you breathe in, they found that they could specifically target the inspiratory muscles.  They also found that this increase in strength produced not just better breathing, but also improvements in a wide variety of things - blood pressure was lowered, sleep was improved, breathlessness was reduced and in some athletes, performance was improved!
Over the coming weeks, we will highlight some of the latest research on inspiratory muscle training - maybe you will see how it can benefit you!