What Does a Breathing Trainer Do? | Respiratory Muscle Training Explained

Whether you’re a runner looking to shave seconds off your mile, a swimmer wanting to hold your breath longer between strokes, or someone recovering from a chest infection, a breathing trainer works by forcing your breathing muscles to work harder than normal. This resistance training builds strength and endurance in the diaphragm and intercostal muscles, leading to measurable improvements in how your body handles physical exertion.

How a Breathing Trainer Actually Works

The device creates a controlled resistance load — typically adjustable via a dial or interchangeable springs — that your respiratory muscles must overcome with each breath. You breathe through a mouthpiece against this resistance, which triggers the same physiological adaptation process as lifting weights for your biceps: the muscle fibers hypertrophy, neuromuscular coordination improves, and the muscles become more fatigue-resistant over time.

There are three training modes to know about:

• Inspiratory muscle training (IMT): Makes inhalation harder, targeting the diaphragm and external intercostals. Most common mode for endurance athletes.
• Expiratory muscle training (EMT): Makes exhalation harder, engaging abdominal muscles and internal intercostals. Often used in respiratory therapy.
• Dual-phase devices: Provide resistance on both inhale and exhale in one session.

Research reviews published in the medical literature have documented performance gains in running, cycling, swimming, and rowing with consistent use. The proposed mechanisms include diaphragm hypertrophy and improved respiratory muscle economy — meaning your breathing muscles simply do more work with less oxygen cost.

Who Actually Benefits From Using One

The evidence splits into two main categories: fitness performance and medical recovery. For athletes, systematic reviews show that six or more weeks of respiratory muscle training can improve time-trial performance and reduce perceived breathlessness during high-intensity effort. Swimmers and rowers appear to benefit most because their sports already challenge breathing mechanics.

On the medical side, clinical populations that may benefit include people with asthma, bronchiectasis, COPD, and those recovering from chest infections or surgery. The devices help with secretion clearance and lung expansion, though outcomes vary by individual condition — these should always be used under clinical guidance for medical applications.

Using a Breathing Trainer: Core Steps

Proper technique matters more than resistance level. For an incentive spirometer type (the clear plastic cylinder hospital patients use), follow this sequence based on Cleveland Clinic instructions:

1. Sit upright and hold the device vertically.
2. Seal your lips around the mouthpiece completely.
3. Inhale slowly and as deeply as possible — you’ll see the piston rise.
4. Hold that full breath for at least five seconds.
5. Exhale slowly and rest before repeating.

For resistance-style breathing trainers used in fitness and therapy: start seated or lying supine with slow breaths of 2–3 seconds each direction. Do 2–3 sets of 10–20 breaths once or twice daily, with 2–4 minutes rest between sets. Most users train 3–7 days per week and should allow at least 3–4 weeks before expecting noticeable results. If you’re ready to buy, our tested roundup of the best breathing trainers breaks down which models suit different goals and experience levels.

Common Mistakes That Kill Results

The most frequent error is confusing a breathing trainer with an incentive spirometer. They look similar but work differently: incentive spirometers encourage deep inhalation without resistance, while breathing trainers add a deliberate load your muscles must overcome. Using one for the other’s purpose wastes your time.

Other pitfalls include poor posture (slouching compresses the diaphragm), starting resistance too high (you want a hard but achievable breath, not a struggle), expecting instant results (meaningful changes take 3–4 weeks minimum), and training when you’re symptomatic with a cold or chest congestion. A good lip seal is also essential — mouthpiece-based devices don’t work well if air leaks around the seal.