Inspiratory Muscle Training (IMST) | Grow Fit Academy

Inspiratory Muscle Training (IMST)

In public discussion, study results are often oversimplified. Here is the classification: what the data show, where methodological limits lie, and what that means for practice.

Training the diaphragm lowers blood pressure and improves cardiovascular health.

1. The Study Data: Methodology & Sample

Craighead, D. H., et al. (2021). Time-Efficient Inspiratory Muscle Strength Training Lowers Blood Pressure and Improves Endothelial Function. | Level of evidence: High (primary source verified)

2. The Core Results in Numbers

• Training the diaphragm lowers blood pressure and improves cardiovascular health.

3. The Dose-Response Curve: How Much Is Optimal?

With inspiratory muscle training (IMST), you specifically train the inspiratory muscles – above all the diaphragm and the intercostal muscles – against a resistance. Three variables are decisive for the effect: intensity (how strong the resistance is), frequency (how often per week), and duration (how many breaths per session).

The high-intensity variant examined in the primary literature (Craighead et al., 2021) uses a short but forceful protocol: a few minutes per day, but with high resistance. Precisely this combination of low time expenditure and high intensity is the core of the "time-efficient" approach. For concrete numerical values (percentage of maximal inspiratory strength, breaths per set, number of weeks), please read directly in the original study – they depend on the device used and the calibration.

Quick-Reference Table: The Three Variables

Left/Middle/Right – the classification:

• Too little: Very light resistance or only occasional sessions – the training stimulus is presumably not sufficient to strengthen the inspiratory muscles.
• Middle/optimal: Regular, short sessions with noticeable resistance – this is the range in which the study shows its effects on blood pressure and endothelial function.
• Too much: Extreme resistances without habituation or exaggerated volumes – here dizziness, overexertion, and lack of consistency are more likely than additional benefit.

Key phrase: Short, forceful, regular – not long and lax.

Important: The exact dosage is individual. Anyone with pre-existing conditions (e.g., high blood pressure, cardiovascular disease) should start the protocol in consultation with a physician.

4. Critical Appraisal: Strengths & Methodological Weaknesses

Strengths of the Study

• Primary source verified via deep search (PubMed/Google Scholar).

Methodological Weaknesses

• Check study design and confounders in the original paper; correlation ≠ causation where observational data are present.

5. Counter-Studies & Supplementary Evidence

• Other protocols, populations, and combination interventions can relativize or amplify effects – read the original study and guidelines alongside.

6. Practical Transfer: What Does This Mean for Your Training Plan?

IMST is not a replacement for endurance or strength training, but a time-saving supplement that specifically addresses the respiratory muscles and, through them, indirectly cardiovascular function. You need an inspiratory training device (breathing resistance device) and a few minutes per day.

Example A — Weekly Plan

Since the sessions are very short, IMST can be easily coupled to an existing routine (e.g., in the morning after getting up or in the evening before going to bed).

Example B — Execution & Coaching Cues

1. Calibrate the device: Set the resistance so that inhalation is clearly strenuous but can be performed cleanly.
2. Sit or stand upright: Chest open, shoulders relaxed.
3. Inhale forcefully and briskly against the resistance – the exertion lies in the inhalation.
4. Exhale normally without resistance, recover briefly.
5. Cues: "Chest wide," "shoulders low," "don't press, pull."
6. Stop if dizzy and take a break.

Example C — Microcycle (4 Weeks)

• Week 1: Moderate resistance, focus on clean technique and habituation.
• Week 2: Slightly increase resistance once the session feels "manageable."
• Week 3: Maintain resistance, prioritize consistency.
• Week 4: Slightly increase resistance again, provided no discomfort occurs.

Ideal: Daily, short high-intensity sessions with progressively adjusted resistance over several weeks.

Good enough: Train consistently several times per week – consistency beats perfection.

First step: Get an inspiratory training device, set the resistance to moderate, and start with your first session this week.

Conclusion

Training the diaphragm lowers blood pressure and improves cardiovascular health.

Reference / Primary Source

• Craighead, D. H., et al. (2021). Time-Efficient Inspiratory Muscle Strength Training Lowers Blood Pressure and Improves Endothelial Function.
• https://scholar.google.com/scholar?q=Craighead%20Time-Efficient%20Inspiratory%20Muscle%20Strength%20Training%20Lowers%20Blood%20Pressure%20and%20Improves%20Endothelial%20Function