Athlete Respiratory Function and Training: A Complete Guide to Breathing Pattern Assessment, Diaphragm Training, and Practical Application

Opening: The Student Who Had “Great Cardio but Couldn’t Climb Wuling”

I once coached an amateur cyclist in his early forties—let’s call him A-Hong. His flat-road power was solid, with a functional threshold power (FTP) around 3.8 W/kg, putting him near the front of the pack among the riverside riding crowd. But every time he hit long climbs—like Wuling or multiple laps of Fengguizui—he would “fall apart” in the second half. It wasn’t his legs that gave out first; he’d start gasping and losing rhythm, his upper body would begin shrugging, his breathing would turn rapid and shallow, and then his power would deflate like a punctured tire, dropping steadily.

The first thing he said to me was: “Coach, is my cardiovascular system just naturally weak?”

I had him lie down, place his hands on his belly, and take a few breaths—and the answer was right there: when he inhaled, his belly pulled inward, his chest lifted up, and his shoulders shrugged. This is the classic “chest-breathing compensatory pattern.” His heart was actually fine; the problem lay in the efficiency and fatigue resistance of his respiratory muscles. When exercise intensity rose and breathing demand increased, that inefficient breathing pattern started “stealing blood from the legs,” making his legs fatigue and ache faster.

In this article, I want to lay out clearly the concepts I’ve built up over more than a decade of coaching athletes at various levels and general fitness populations, combined with ongoing reading of exercise physiology and sports medicine literature: breathing is not just “inhale and exhale”—it’s an athletic capability that can be assessed, trained, and can either drag down or support your performance.

---

1. Concepts and Scientific Foundations: Why Respiratory Muscles Affect Athletic Performance

1. The Real Star of Breathing Is the Diaphragm

We often say “breathe with the lungs,” but the lungs themselves have no muscle—they are passively expanded and compressed. The real work is done by the respiratory muscles, the most important of which is the diaphragm—a dome-shaped muscle located between the chest and abdominal cavities.

When you inhale, the diaphragm contracts and descends, increasing the volume of the chest cavity and “sucking” air in; exhalation (at rest) is mostly passive recoil. Besides the diaphragm, there are also the intercostal muscles, the abdominal muscles, and the accessory respiratory muscles recruited during exercise (scalenes, sternocleidomastoid, etc.).

The key concept is this: the diaphragm is a skeletal muscle that gets tired, just like your quadriceps. It has muscle fibers, metabolic demands, and it fatigues under prolonged high-intensity use.

2. Respiratory Muscle Fatigue Is Real—and It Drags Down Your Legs

In the past, many people assumed “the limits of exercise lie in cardiac output and muscles,” with the respiratory system playing only a supporting role. But over the past decade-plus, exercise physiology research has clarified a mechanism: the respiratory muscle metaboreflex.

Here’s roughly how it works (in the plainest terms I can manage):

1. When you exercise at high intensity with heavy, rapid breathing, the diaphragm and other respiratory muscles begin to fatigue and accumulate metabolic byproducts.
2. The body detects that the respiratory muscles are “about to fail” and triggers a survival reflex: blood flow is preferentially redirected to the respiratory muscles, because breathing cannot stop.
3. To shift blood there, the body constricts blood vessels in the working limb muscles, so your legs (or arms) receive less blood flow.
4. The result: your legs fatigue and ache faster, and you’re forced to slow down—but your subjective sensation is often “my legs are spent,” when the root cause is that the respiratory muscles gave out first.

Research also shows that if you deliberately fatigue the respiratory muscles with breathing maneuvers before exercise, subsequent time-to-exhaustion is significantly shortened; conversely, unloading the respiratory muscles with low-density gas or mechanical ventilatory support delays diaphragm fatigue and prolongs exercise duration. These two directions of experiments point to the same conclusion: respiratory muscle fatigue genuinely limits your endurance performance (Journal of Applied Physiology, 2008; PMC review, see references at the end).

A-Hong’s “falling apart in the second half” is the classic picture of the metaboreflex being triggered early and violently.

2.5 Why “Shallow and Rapid” Breathing Is Especially Costly: The Concept of Anatomical Dead Space

Here’s a concept many people overlook but is extremely practical—anatomical dead space.

Not all the air you inhale with each breath actually participates in gas exchange. The air in the “tubing” from the nasal cavity, trachea, and down to the larger bronchi never reaches the alveoli for exchange; that volume is called dead space, roughly 150 milliliters in adults.

What does this mean? Here’s a practical arithmetic example (values are for conceptual illustration only):

• Shallow, rapid breathing: Suppose each breath brings in 300 mL at 30 breaths per minute. Effective exchange ≈ (300 − 150) × 30 ≈ 4,500 mL per minute.
• Deep, slow breathing: Suppose each breath brings in 600 mL at 15 breaths per minute. Effective exchange ≈ (600 − 150) × 15 ≈ 6,750 mL per minute.

See the key point? Both have the same total ventilation (minute ventilation) of 9,000 mL per minute, so they look identical—but the deep, slow pattern delivers 50% more “effective” exchange. Because shallow, rapid breathing wastes a large proportion of effort “blowing back and forth through that 150 mL of dead tubing.”

This is why A-Hong’s rapid, shallow breathing meant he was working hard to inhale yet exchanging air inefficiently—every breath was doing wasted work, and he was wearing out his respiratory muscles faster, triggering the metaboreflex early. Once you understand this, you’ll see why I emphasize so strongly “breathe deep and slow, and empty the exhalation completely.”

3. What Respiratory Muscle Training Can and Cannot Improve

I want to be honest here, because public expectations for breathing training are often oversold.

According to multiple systematic reviews and meta-analyses (see references at the end), the evidence for respiratory muscle training (especially inspiratory muscle training, IMT) roughly falls into:

• What helps: time trial performance, time-to-exhaustion, intermittent exercise performance (e.g., Yo-Yo tests), inspiratory muscle strength and endurance, and subjective ratings of “breathlessness” and perceived exertion. Mechanistically, this mainly comes from delaying/attenuating the respiratory muscle metaboreflex, reducing respiratory muscle fatigue and dyspnea.
• What typically doesn’t change: maximal oxygen uptake (VO₂max). Most studies show no significant improvement in VO₂max after breathing training. This is actually an important clue—it supports the view that “in healthy people, exercise is not limited by the lungs’ gas-transport capacity.” But don’t forget: VO₂max is not the sole determinant of endurance performance. Time trial results, fatigue resistance, and other “under-the-hood” qualities can still improve.

So my positioning for students is simple: breathing training is not magic that skyrockets your VO₂max; it’s an auxiliary tool that helps you “hold the second half together and raise the ceiling on breathlessness, without changing the existing engine.” Get the expectations right, and the results will satisfy you.

---

2. Breathing Pattern Assessment: Understand the Problem First, Then Talk Training

I strongly oppose telling students to just buy an inspiratory trainer and grind away. Without assessing the breathing pattern first, it’s like adding heavy weight without checking the movement. Below are the layers of assessment I actually use with people—you can do a preliminary check at home too.

1. Static Breathing Pattern Check (Supine)

This is the most basic check and the one that reveals problems at a glance.

Method: Lie flat, knees bent, one hand on the chest and one hand just above the navel. Inhale naturally through the nose, and observe which hand moves first and how much.

Observation Item	Ideal (Diaphragmatic-Dominant)	Needs Correction (Chest-Breathing Compensation)
Belly on inhalation	Clearly bulges outward, moves first	Barely moves, or even pulls inward
Chest on inhalation	Rises slightly, moves second	Rises significantly, moves first
Shoulders	Barely move	Clearly shrug upward
Breathing rate (at rest)	About 10–16 breaths per minute	Faster and shallower
Subjective sensation	Smooth, deep, effortless	Feels like you have to “force the inhale” to get air

The first time A-Hong did this check, the hand on his chest moved a lot, the hand on his belly barely moved, and his shoulders shrugged up—he hit every item in the right-hand column.

2. Breathing Rhythm and Airway Patency (Dynamic)

Next, I look at the dynamic aspects:

• BOLT Breath-Hold Test (Conceptual Reference): After a calm exhale, pinch your nose and hold your breath, recording the seconds until you feel the “first clear urge to breathe.” This number reflects your CO₂ tolerance and breathing control, and can serve as a personalized metric for long-term tracking (compare against yourself, not others—individual variation is large).
• Breathing Observation During Exercise: When riding a trainer or running on a treadmill, I watch whether the athlete’s breathing becomes rapid and shallow near threshold intensity, whether the upper body starts to tense up with shrugged shoulders, and whether they can maintain a steady breathing rhythm (e.g., 3 steps inhale, 2 steps exhale while running).

3. When to Seek Professional Evaluation or Medical Attention

I want to emphasize this specifically: breathing difficulties should not automatically be treated as “undertrained respiratory muscles.” If you have any of the following conditions, see a doctor first—don’t just bury your head in breathing trainer workouts on your own:

• Wheezing, chest tightness, chest pain, or noticeable coughing during or after exercise, or a prior diagnosis of asthma or exercise-induced bronchoconstriction.
• Easily getting short of breath at rest, or being out of breath after climbing a flight of stairs, disproportionate to the exertion level.
• A history of cardiovascular disease, hypertension, heart disease, or diabetes, or a relevant family history.
• Breathing difficulties accompanied by dizziness, palpitations, or fainting.

Seeking medical care in Taiwan is actually very convenient. Under the National Health Insurance (NHI) system, pulmonology, cardiology, and rehabilitation medicine departments can all help, and pulmonary function tests (such as spirometry) can be performed if necessary. Rule out pathological factors first, then talk about training—the order cannot be reversed.

4. A Self-Check Comparison Table

To help you systematically self-assess at home, I’ve organized the common observation points into a table. After going through it, you can get a rough idea of which category you fall into and which level you should start training from.

Check Item	Method	Green Light (Good Condition)	Yellow Light (Trainable/Improveable)	Red Light (See a Doctor First)
Resting Breathing Pattern	Lying down, hands on chest and abdomen	Abdomen moves first, shoulders stay down	Chest breathing compensation, slight shoulder shrugging	Short of breath at rest, chest tightness
Resting Breathing Rate	Count breaths for one minute	About 10–16 breaths	Somewhat fast, somewhat shallow	Clearly too fast and labored
Breath-Hold Seconds (Personalized)	Hold breath after calm exhale	Feels comfortable to yourself	Urge to inhale comes quickly	Accompanied by palpitations or dizziness
Upper Body During Exercise	Ride/run at threshold intensity	Shoulders and neck relaxed	Shoulders start shrugging and tensing	Wheezing, chest pain
Performance in the Latter Half	Late stages of a long climb or long run	Small drop-off, controllable	“Breath gives out before the legs do”	Dizziness, unable to finish

Interpretation Guidelines: All green means you can proceed directly to inspiratory muscle training; any yellow light means start with Level 1 breathing pattern rebuilding; if there is even one red light, see a doctor first—training can wait.

---

III. Practical Methods: Diaphragm Training and Respiratory Muscle Training Plans

Only after the assessment is complete and red flags requiring medical attention are ruled out do we move into training. I divide the training into three levels: Foundation Rebuilding (Breathing Pattern) → Respiratory Muscle Strength (Inspiratory Muscle Training) → Sport-Specific Integration (Breathing During Exercise).

Level 1: Rebuilding Abdominal Breathing and Diaphragm Activation

This level requires no equipment, yet it’s the step most people skip and the most important one. Going straight to inspiratory resistance training without rebuilding your breathing pattern is like adding load to a faulty movement pattern—it will only reinforce chest-breathing compensation even more.

Core Exercise: Supine Abdominal Breathing (Including a Light-Load Version)

1. Lie flat with knees bent, one hand on your chest and one on your abdomen.
2. Inhale slowly through the nose for 3–4 seconds, letting only the hand on your belly rise while the hand on your chest stays as still as possible.
3. Exhale slowly through the mouth or nose for 4–6 seconds, letting your belly naturally fall back down.
4. Progression: Place a book weighing about 1–2 kg on your abdomen as light resistance to force the diaphragm to work.

Week	Daily Sessions	Duration per Session	Focus
Weeks 1–2	Once in the morning, once at night	5 minutes	First aim for “belly moves, chest doesn’t,” take it slow
Weeks 3–4	Once in the morning, once at night	8 minutes	Add the light load of a book on the belly
From Week 5	Once daily	8–10 minutes	Try to maintain abdominal breathing in side-lying, seated, and standing positions

I usually require athletes to practice this level until abdominal breathing happens automatically without thinking, before moving to the next level. Ah-Hong spent about three weeks on this level before his resting breathing finally stabilized into abdominal breathing and his shoulders stopped shrugging.

Level 2: Inspiratory Muscle Training (IMT)

This is the area with the strongest evidence in the research. The most common tool on the market is the inspiratory pressure threshold device, which works by providing a fixed resistance during inhalation, forcing the inspiratory muscles to work hard—similar to “weight training for the diaphragm.”

A widely used and easy-to-remember introductory protocol in the literature is:

• 30 inhalations per session
• 2 sessions per day (one in the morning, one at night)
• Resistance set at approximately 50–60% of your maximal inspiratory pressure (on most devices, this is a matter of turning a dial; practically, aim for an intensity that is “effortful but allows you to complete all 30 reps continuously, with the last few reps feeling somewhat challenging”)
• Train about 5–6 days per week, for at least 4–6 weeks before noticing results

Training Phase	Resistance Intensity (Conceptual)	Volume per Session	Frequency	Goal
Adaptation Phase (Weeks 1–2)	Low (can complete easily)	30 reps × 1–2 sets	5 days/week	Learn to engage inspiratory muscles without shrugging shoulders
Progression Phase (Weeks 3–6)	Moderate (last few reps are challenging)	30 reps × 2 sets	5–6 days/week	Build inspiratory muscle strength
Maintenance Phase (From Week 7)	Gradually increase with progress	30 reps × 2 sets	3–4 days/week	Preserve gains, avoid overtraining

Key Execution Points (What I Most Often Correct):

• Use abdominal-driven force throughout—don’t shrug your shoulders and strain with your neck muscles again; that’s wasted effort and even deepens the bad habit.
• Inhale quickly and deeply, exhale relaxed, with a brief pause between each rep.
• Increase resistance gradually—don’t crank it to the maximum on day one, or your respiratory muscles will be so sore the next day that you can’t continue.
• Respiratory muscles need recovery just like any other muscle—you don’t need to train at max intensity every day; 3–4 times per week during the maintenance phase is plenty.

Level 3: Integrating Breathing into Sport

After all that respiratory muscle training, the ultimate goal is to “use it on the race course.” At this level, I arrange:

• Rhythmic Breathing: Match breathing to a fixed step count while running (e.g., 3 steps inhale, 3 steps exhale on easy runs; 2 steps inhale, 1 step exhale at higher intensity); on the bike, deliberately maintain deep, steady exhalations on climbs to avoid rapid, shallow breathing.
• “Active Exhalation” Cue During Climbs/Intervals: Many people, when fatigued, become “all about inhaling and not exhaling fully,” which reduces ventilation efficiency. I remind athletes to focus on “forcibly exhaling completely”—the inhalation will then come naturally and smoothly.
• Breathing Activation in Warm-Up: Before formal training or competition, use low-resistance inspiratory muscle training or a few sets of deep abdominal breathing as a “respiratory muscle warm-up” to get the diaphragm into a working state first.

A Six-Week Integrated Weekly Plan You Can Copy Directly

Many trainees still ask me after reading the three-tier training: “So how exactly do I schedule my week?” I’ve put together the most practical six-week example for amateur cyclists/runners below. This is a “bonus” layered on top of your main training plan, not a replacement for it.

Day	Breathing Session Content	Main Session Recommendations
Monday	AM: IMT 30 reps × 2; PM: Diaphragmatic breathing 8 min	Easy aerobic ride/run
Tuesday	AM: IMT 30 reps × 2	Interval day (breathing only in the morning to avoid fatigue stacking)
Wednesday	PM: Diaphragmatic breathing + rhythmic breathing practice 10 min	Recovery day or rest
Thursday	AM: IMT 30 reps × 2; PM: Diaphragmatic breathing 8 min	Threshold-intensity training
Friday	Rest (respiratory muscles need recovery too)	Complete rest or stretching
Saturday	Pre-race style breathing warm-up + use “active exhalation” during the main session	Long ride/long run (put the integrated technique into practice)
Sunday	PM: Diaphragmatic breathing relaxation 8 min	Easy ride/run or rest

Programming logic: Schedule the high-intensity IMT work in the “morning” and on “non-hardest main session days,” to avoid respiratory muscle fatigue conflicting with intervals and long distances. The long ride/long run is the weekend centerpiece, perfect for practicing “integrating breathing into real exercise.” After six weeks, go back and redo the self-check comparison table from Section 2—you’ll feel a clear difference.

---

4. Common Mistakes and Corrections

Over the years, I’ve seen too many people “train their breathing but see no results,” and the problem almost always comes down to the points below.

Mistake 1: Skipping Breathing Pattern Rebuilding and Buying Equipment to Suck Hard Right Away

This is the most common one. If your breathing pattern is still compensatory chest breathing, and you go hard on an inspiratory muscle trainer, the result is reinforcing the wrong pattern of shrugged shoulders and shallow, rapid breathing even more firmly.

Correction: You must first get Layer 1 diaphragmatic breathing stable before adding resistance training. The order cannot be skipped.

Mistake 2: Getting the Intensity and Volume Wrong—Heavier Isn’t Always Better

Some people crank the resistance all the way to max and train hard every day. Two or three days later, their respiratory muscles are so sore that even normal exercise is affected. Respiratory muscles are muscles—overtraining produces the opposite effect.

Correction: Use “being able to complete 30 reps consecutively, with the last few reps feeling challenging” as the intensity benchmark; if there’s noticeable soreness, cut the volume or take a rest day.

Mistake 3: Only Training Breathing and Ignoring Main Sessions

Breathing training is supplementary, not the main course. I’ve met people who thought that training breathing meant they could ride or run less. That completely misunderstands its role. VO₂max generally won’t skyrocket from breathing training alone; endurance and strength training in your main sport remain the foundation.

Correction: Treat breathing training as a “bonus item that takes 10 minutes morning and evening,” and keep your main training plan as usual.

Mistake 4: Mistaking Pathological Breathing Difficulty for “Not Training Enough”

I emphasized this earlier, and it’s worth repeating. Wheezing during exercise, chest tightness, chest pain, or breathlessness disproportionate to the exercise load can all be warning signs of asthma, cardiovascular issues, and more. Pushing through it as if it were weak respiratory muscles could delay necessary medical care.

Correction: If red-flag symptoms appear, seek medical evaluation first. Under Taiwan’s National Health Insurance, both pulmonology and cardiology clinics are very accessible.

Mistake 5: Forcing Shallow, Rapid Breathing in Taiwan’s Hot, Humid Environment

Taiwan’s summers are hot and humid—riverside paths and mountain roads routinely hit 32°C+ with 70–80% humidity. In high heat, heart rate is naturally elevated and ventilation demand is higher. If your breathing is also shallow and fast, the metaboreflex kicks in earlier, and you “blow up” faster.

Correction: During hot-weather training, deliberately slow down and deepen your breathing, and make your exhalation complete, while also lowering target intensity and staying on top of fluids and electrolytes. Don’t fight the weather head-on.

---

4.5. Case Studies of Three Real-Life Scenarios

No matter how much theory I explain, it’s better to see how actual situations are handled. The following case scenarios are set up for teaching purposes, but the handling logic is exactly the same as what I do with my real trainees.

Case A: An Endurance Cyclist Who Always “Loses His Breath” After 60 km on the Riverside

Situation: Xiao Lin loves long riverside rides. The first 50 km are smooth, but past 60 km his breathing starts to fall apart, his upper body tightens up, and his average speed drops significantly.

Assessment findings: His resting breathing is actually fine. The problem is “insufficient fatigue resistance of the respiratory muscles over time,” combined with hydration and fueling not keeping up—so when fatigue sets in, he regresses to shallow, rapid breathing.

Handling:

• Layer 1 diaphragmatic breathing took only two weeks to consolidate (he was already decent at it).
• Layer 2 IMT focused on “endurance-oriented” work—not chasing maximum resistance, but instead doing 30–40 reps per set at moderate intensity, aiming to train fatigue resistance rather than maximal strength.
• Set “breathing reminder points” during long rides: every 15 km, actively do 10 deep, slow exhalations to pull the rhythm back.
• Adjusted his fueling schedule as well.

Result: Two months later, the speed drop in the latter part of the same route was noticeably smaller, and the “losing breath” threshold pushed back from 60 km.

Case B: An Interval-Type Athlete Who Excels at Short Bursts but Gets Completely Winded After One Effort

Situation: A Kai trains track/sprint. His single efforts are powerful, but after repeated sprints, recovery is slow, and he subjectively feels “so winded his chest feels tight.”

Assessment findings: This type of interval discipline is exactly the population where research shows IMT is most helpful—repeated high-intensity efforts rapidly fatigue the respiratory muscles and repeatedly trigger the metaboreflex.

Handling:

• IMT took a “strength-oriented” approach: higher resistance, keeping reps at 30, with adequate rest and recovery.
• Added “active exhalation recovery after sprints”: after each effort, deliberately do several deep, long exhalations to speed up the return of rhythm and ventilation.

Result: The “winded and tight” feeling between repeated sprints decreased, and subjective recovery between efforts felt faster.

Case C: A Runner Who Mistook Asthma for “Not Training Enough” and Pushed Through (The Most Important Cautionary Case)

Situation: A Shan often wheezes when running and coughs for a long time after exercise. She always thought it was “weak respiratory muscles” and bought equipment to train hard.

Handling: The moment I heard “wheezing + prolonged coughing after exercise,” I slammed on the brakes and told her to see a pulmonologist first. It was later confirmed as exercise-induced bronchoconstriction. Only after medical management and good control did she gradually add breathing and exercise training under professional guidance.

The key takeaway from this case: Red-flag symptoms are not a training problem; they’re a medical problem. Taiwan’s NHI makes seeing a doctor easy—don’t let “training through it” delay the appointment you need.

---

5. Actionable Recommendations for Readers at Different Levels

Everyone starts from a different point, so I’ve divided the recommendations into three categories. Just find where you fit.

For Exercise Beginners / General Healthy Population

• Learn diaphragmatic breathing first: Do 5 minutes of supine diaphragmatic breathing morning and evening, until it becomes automatic without thinking. This step is especially impactful for sedentary people and those who habitually shrug and hold tension.
• No rush to buy equipment: Build up your breathing pattern and regular exercise (3 times per week, 30 minutes of moderate intensity each), and you’ll notice a clear improvement in how your body feels.
• If you experience any exercise-related breathlessness or chest tightness, see a doctor first—don’t push through it as if it were a training problem.

For Amateur Athletes with a Training Base (Like A Hong)

• Layer 1 diaphragmatic breathing rebuilding for 2–3 weeks → Layer 2 IMT for 4–6 weeks, progressing step by step according to the earlier table.
• Integrate breathing into your main sessions: actively exhale on climbs and intervals, and maintain rhythmic breathing.
• Track with personalized metrics: breath-hold time, whether you can hold power/pace in the second half of the same climb, and whether perceived exertion drops—these are more real than any advertised number.
• Three months later, A Hong came back: on the same long climb, the second half no longer “fell apart completely,” subjective breathlessness was noticeably pushed back, and power drop was much smaller. It wasn’t that his VO₂max changed—it was that the breathing short board had been filled in.

For Advanced / Competitive Athletes

• Periodize your breathing training: In the off-season, focus on accumulating inspiratory muscle strength (progressive phase); closer to competition, switch to maintenance volume to avoid respiratory muscle fatigue affecting your main sessions.
• Design for your specific discipline: For sports involving intervals and repeated high-intensity efforts (such as track, cyclocross, ball sports), research shows IMT is particularly beneficial for interval performance and fatigue resistance.
• Include respiratory muscle activation in your pre-race warm-up, getting the diaphragm into working mode early.
• Seek professional sports physiology / sports medicine assessment when necessary to quantify respiratory muscle strength and lung function for more precise, individualized prescriptions.

---

6. Frequently Asked Questions (FAQ)

Q1: How long does it take to feel the effects of breathing training?
Most studies use intervention periods of 4–6 weeks or longer before changes in inspiratory muscle strength and performance are observed. In practice, I ask athletes to complete at least 6 weeks of serious training before evaluating results—don’t expect miracles after just three days.

Q2: Do I have to buy an inspiratory muscle trainer?
Not necessarily. The first layer—rebuilding diaphragmatic breathing—requires no equipment at all, and many people already feel a difference after this step. If you want to further train inspiratory muscle strength, threshold-type trainers do make it convenient to quantify intensity, but they are a bonus, not a necessity.

Q3: Will breathing training improve VO₂max?
Most evidence shows it does not significantly improve VO₂max. Its value lies in delaying respiratory muscle fatigue, reducing breathlessness and perceived exertion, and preserving performance in the latter half—not in increasing the engine’s displacement. Set the right expectations and you won’t be disappointed.

Q4: Can people with asthma do this?
This needs to be individualized and discussed with a physician first. Some people with asthma or exercise-induced bronchoconstriction can still exercise and do breathing training under good control, but it must be done under professional supervision—don’t train on your own.

Q5: What should I watch out for in Taiwan’s hot, humid weather?
High heat and humidity raise both heart rate and ventilatory demand, making the metaboreflex more likely to kick in early. I recommend lowering target intensity, deliberately deepening and slowing your breathing, making sure to fully exhale, and staying on top of fluid and electrolyte intake.

Q6: Are there risks to breathing training?
For healthy individuals, progressive breathing training carries very low risk. However, if you overdo it or push intensity too hard, you may experience respiratory muscle soreness or even dizziness (from hyperventilation). If you feel unwell, stop and slow down; if you have red-flag symptoms, seek medical attention.

Q7: Is nasal breathing or mouth breathing better?
At low intensity, nasal inhalation is encouraged—it helps humidify, filter, and maintain a deeper, slower rhythm. But when intensity rises and ventilatory demand increases, using your mouth to assist inhalation is perfectly natural; don’t force nasal breathing and leave yourself short of air. The key is always “deep and steady, exhale fully,” not which orifice you use.

Q8: Can I still improve at an older age?
Yes. Respiratory muscles are like any other skeletal muscle—starting regular, progressive training at any age can improve strength and fatigue resistance. Older adults should especially build from the first layer of diaphragmatic breathing, keep intensity conservative, and consult a physician first if they have chronic conditions.

---

Conclusion: Breathing—Your Most Underrated Piece of the Training Puzzle

Back to Ahong’s story. He initially thought he was “born with poor cardiorespiratory fitness,” but the real bottleneck was an inefficient, fatigue-prone breathing pattern and respiratory muscles. When we filled in this breathing piece, he didn’t become a different person—he reclaimed the latter-half performance that had been wasted.

I often tell my athletes: everyone trains the “engines”—legs, heart—like crazy, but breathing is often that neglected piece that silently caps your ceiling. It can be assessed, it can be trained, and for many people the return on investment is surprisingly high—especially for those who “always fall apart in the second half.”

If you’re the type who finds that on the latter part of a climb or the back half of a run, “the breath gives out before the legs do,” why not start today by lying down, placing a hand on your belly, and taking a few good deep breaths? This step costs nothing and requires no equipment, yet it could be the starting point of your next breakthrough.

---

This article is educational content and does not replace individual diagnosis or treatment advice from a physician, physical therapist, or nutritionist. If you have a history of cardiovascular disease, asthma, or other chronic conditions, or if you experience chest tightness, chest pain, wheezing, dizziness, or other symptoms during exercise, please consult a doctor first and undergo individualized breathing training under professional guidance.

References

• Exercise-induced respiratory muscle fatigue: implications for performance (Journal of Applied Physiology): https://journals.physiology.org/doi/full/10.1152/japplphysiol.01157.2007
• Insights into the role of the respiratory muscle metaboreflex (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC2277009/
• Inspiratory muscle training attenuates the human respiratory muscle metaboreflex (PMC): https://pmc.ncbi.nlm.nih.gov/articles/PMC2277000/
• The effectiveness of respiratory muscular training in athletes: A systematic review and meta-analysis (ScienceDirect): https://www.sciencedirect.com/science/article/abs/pii/S1360859225000130
• Inspiratory Muscle Training in Intermittent Sports Modalities: A Systematic Review (PMC): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7344680/
• Practical Application of Respiratory Muscle Training in Endurance Sports (NSCA, Strength & Conditioning Journal): https://journals.lww.com/nsca-scj/fulltext/2024/12000/practical_application_of_respiratory_muscle.5.aspx

Related Reading

• Respiratory Muscle Training for Runners: The Science of Diaphragm Strengthening and Running Endurance
• Respiratory Physiology in Exercise: Ventilation, Respiratory Muscles, and Performance—The Overlooked Second Engine
• Breathing Strategies for Cycling: The Connection Between Rhythmic Breathing and Core Stability
• Respiratory Muscle Training for Cyclists: The Benefits of Respiratory Muscle Strengthening for Riding Endurance