Open with something relatable. Runners strength train their glutes, calves and core. We do intervals to improve VO2 max. But most of us never think about deliberately training the muscles responsible for breathing. However, lately a growing number of social posts have been asking us to think about this, particularly with breath resistance devices.
We took a closer look at whether resistance breathing devices are actually worth adding to your training, or if they’re just another gadget taking up space in your gym bag.
Is there a certain way to breathe during exercise? Could strengthening your breathing muscles actually help your running?
We’ll take a look at what resistance breathing devices do, whether it’s better to breathe only through your nose, and if they’re worth adding to your training.
What Is a Resistance Breathing Trainer?
Think of a resistance breathing device as a piece of “gym equipment” to strengthen your breathing muscles.
As you breathe through the device, it creates resistance that forces your diaphragm and the muscles between your ribs to work harder than they normally would.
Over time, just like with lifting weights, those muscles become stronger.
Why does that matter for runners?
During harder runs and even on race day, your breathing muscles are working double time. If they begin to fatigue, your body actually redirects blood flow toward them to keep you breathing.
The stronger your breathing muscles are, the longer they can keep working before they fatigue, which means your legs can keep pumping at that faster effort.
Does this mean that resistance breathing devices can replace speed workouts and long runs?
Absolutely not.
It’s not a magic fix or a shortcut to getting faster.
If you’re curious, it could be a fun tool to experiment with, but it’s far from a must-have.
- Expand a Lung – $9.99 – Coach Amanda has been playing with this option after the Brain Hacking podcast!
- Ouma Smart Breathing Trainer – $99 – Love that it has an app to actually walk you through workouts
- AiroFit – $349 – Elite training device designed specifically for endurance athletes (like serious Olympic performances)
Why The Focus on Improving Breathing for Performance?
Overall, studies suggest that respiratory muscle training, and particularly inspiratory muscle training (IMT), can improve respiratory muscle strength and may improve endurance performance. A systematic review and meta analysis of athletes found improvements in inspiratory muscle strength along with performance measures including time trials and exercise endurance.
A more recent 2025 systematic review and meta analysis looked at 25 studies involving 522 athletes. Researchers again found that respiratory muscle training significantly improved inspiratory muscle strength.
But stronger breathing muscles don’t automatically mean you’re going to run a faster marathon, so let’s break down what the research actually tells us.
1. Respiratory Muscle Strength
This is where the evidence is probably the clearest.
Just like repeatedly loading your calves can make them stronger, repeatedly making your breathing muscles work against resistance can make those muscles stronger.
Researchers often measure this using maximal inspiratory pressure (MIP), which is essentially a measure of how forcefully you can inhale.
The 2025 meta analysis found a significant improvement in MIP following respiratory muscle training across 18 studies involving athletes from different sports.
We see similar results when researchers look specifically at runners. So yup, you can make your breathing muscles stronger with training.
2. It May Make Hard Running Feel Easier
Think about those final few intervals of a hard workout or the last miles of a race. Your legs are working hard, but breathing can also start to feel like part of what’s limiting you.
Training the respiratory muscles may reduce some of that sensation of respiratory effort.
For example, the 2025 study of amateur runners measured both perceived exertion and perceived breathlessness after eight weeks of inspiratory muscle training. The researchers found improvements in exercise tolerance along with reductions in perceived exertion and breathlessness, particularly with higher intensity respiratory training.
The benefit may not simply be that you can breathe “more.” It may be that your breathing muscles can handle the workload with less fatigue, helping a hard effort feel more manageable.
And as every runner knows, perception is reality!
3. Improving CO2 Capacity
So what does improving your CO2 capacity mean?
As you run harder, carbon dioxide (CO2) naturally builds up in your body. You may think you’re running out of breath when it’s actually your rising level of CO2.
Better breathing means getting more oxygen flowing to your muscles as the training load increases.
What happens when we don’t breathe well:
- Muscles lacking oxygen become tight.
- The heart is unable to pump as efficiently.
- The nervous system feels frazzled.
- Your brain slows down.
- The body’s ability to produce energy is decreased.
The more comfortable your body becomes with that uncomfortable feeling, the less likely you’re to start breathing hard earlier than you need to.
Sure, using a resistance breathing device can help improve your CO2 capacity, but it’s never going to replace your actual training.
You still need to build your aerobic fitness through consistent running and workouts. Just think of breath training as another tool in your toolbox to keep building your fitness.
What About VO2 Max?
Respiratory muscle training doesn’t necessarily increase VO2 max.
And that’s important because we tend to assume anything that helps endurance performance must be improving VO2 max.
In the recreational runner study that found faster 1,500 meter performances, researchers found no change in maximal aerobic capacity or pulmonary function. In other words, the runners didn’t suddenly develop a larger aerobic engine. They got better at using the system they already had.
Do You Need to Breathe Only Through Your Nose?
Short answer? No.
Nasal breathing has become a bit of a buzzword over the last few years, and there are certainly some benefits. But it’s not something that you must do as a runner.
In fact, trying to force yourself to breathe only through your nose during workouts or races is often more frustrating than helpful, especially if you’re newer to running and breathing already feels challenging.
As your pace picks up, your body naturally switches to mouth breathing because it just needs more air.
Think about the last time you really pushed the pace during intervals or raced a 5k. Chances are, you weren’t breathing only through your nose.
And that’s completely normal.
Mouth breathing isn’t bad form or something that needs “fixing”. It’s simply your body’s way of getting the airflow it needs to keep up with the effort.
Most runners will switch between breathing through their nose and mouth depending on the pace. If you’re curious about breathing only through your nose, try it on easy runs or recovery days.
But when it’s time for speed work or race day, let your breathing adjust to the effort so you can focus on running your best.
Here are some tips for how to breathe easier while running.
Can Resistance Breathing Devices Help Runners?
Many of these studies are small, training protocols vary considerably, and researchers have studied athletes from a variety of sports and fitness levels. That’s why I wouldn’t put respiratory muscle training in the same category as foundational training tools like consistent mileage, speed work, strength training, fueling and recovery.
But there is enough evidence here that I also wouldn’t dismiss it as another gimmicky performance gadget.
One study found that healthy adults who added breathing resistance training to their regular workouts for six weeks improved their breathing muscle function, exercise capacity, and the point at which breathing started to feel much harder during exercise.
What does that actually mean?
Think about that last mile of a race or the final interval of a workout.
When your breathing starts to feel like what’s holding you back, stronger breathing muscles may help you stay more comfortable for a little longer. Well, comfortably uncomfortable, I guess you would say here.
If you decide to give it a try, think of it like you would a strength training or mobility session.
It’s there to support your running.
You’re still going to see the biggest changes by being consistent with training, recovery, and putting in the miles week after week.
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