Effects of diaphragmatic deep breathing exercises on prehypertensive or hypertensive adults: A literature review

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Citation

Yau KK, Loke AY. Effects of diaphragmatic deep breathing exercises on prehypertensive or hypertensive adults: A literature review. Complement Ther Clin Pract. 2021 May;43:101315. doi: 10.1016/j.ctcp.2021.101315. Epub 2021 Jan 26. PMID: 33530033.

4 FUNDAMENTALS

 

1. Essential Background Material

 

Hypertension and prehypertension (high blood pressure) are present in about 1 in 4 people globally.  They both increase the likelihood of cardiovascular disease, making it critical that people control their blood pressure.

 

These conditions are characterized by increased sympathetic nervous system activity and decreased parasympathetic nervous system activity, especially during stressful situations (see Thought #2 here for more).

 

Slow deep breathing (SDB) has been shown to reduce blood pressure and improve nervous system health by reducing sympathetic activity. Moreover, SDB reduces psychological stress and anxiety, critical drivers of the excess sympathetic activity causing high blood pressure.

 

So, SDB is a proven treatment option for controlling high blood pressure.

 

The uniqueness of this literature review was that it synthesized findings to provide practical guidance for voluntary and device-guided SDB, specifically for people who already have hypertension and prehypertension.

 

 

2. What Did this Research Do?

 

This review collected studies published since 2010 examining the effects of SDB (either voluntary or device-guided) in hypertensive and prehypertensive adults. 

Overall, 13 studies were included in the review. Seven used voluntary SDB, where participants were taught to breathe slowly by counting in their heads. The other six used device-guided SDB, where a device provided the breathing cues.

Five studies had people with prehypertension with systolic blood pressure (SBP) from 120 – 139 mmHg and/or diastolic blood pressure (DBP) from 80-98 mmHg who were not using medication.  The other 8 studies had people with stage I or II hypertension (SBP 140-160 and DBP 90-100) using medications.

 

All 13 studies differed in SDB protocol, length, and duration.For example, some had a breathing practice twice weekly, and others were twice daily.Significantly, however, all of them were rated “moderate to good” based on the “Quality Assessment Tool for Studies with Diverse Designs (QATSDD).”

 

 

3. What Were the Major Findings?

 

  • All 13 studies showed significant reductions in blood pressure in hypertensive and prehypertensive individuals. 

  • Although less consistent, SDB also showed a general trend in lowering resting heart rate (only five studies measured resting HR, and 3 showed improvements).

  • Three studies measured HRV and found significant improvements.

  • Three studies included measurements of mean arterial pressure (MAP).  Two found significant reductions in MAP.

  • Only one study measured anxiety and depression scores.  It showed a significant reduction in anxiety but not depression.

  • One study measured quality of life and did not find significant changes.

  • Overall, they found that practicing slow breathing between 6 to <10 breaths a minute for at least 10 minutes a day can significantly improve blood pressure if practiced consistently for weeks or months. 

 

4. Why Do These Results Matter?

The finding across all 13 studies that slow breathing improves blood pressure in hypertensive and prehypertensive patients shows that this simple intervention can potentially decrease the likelihood of cardiovascular complications in this susceptible population. The results also confirm that SDB reduces sympathetic activity and improves autonomic function in this population.

Moreover, the finding that MAP was reduced in two studies is meaningful. A reduction in MAP indicates better blood flow to major organs during every cardiac cycle. Better blood flow to vital organs further supports the notion that SDB can reduce the risk of cardiovascular-related problems in this population.

 

Lastly, these results are significant because they show that no device is necessary to get the benefits. This means we already have all the tools we need to reduce our blood pressure.It’s cost-free and effective.

 

 

 

1 BIG TAKEAWAY

Slow breathing between 6 to less than 10 breaths a minute, with or without a device, for at least 10 minutes a day for 4+ weeks significantly reduces blood pressure, improves blood flow to vital organs, and improves autonomic dysfunction in people with hypertension or prehypertension.

 

 

1 PRACTICAL APPLICATION

 

Usually, such heterogeneity among studies is undesirable if we want to generalize the results.  However, in this case, it’s even more potent because we learn that we can use a device, count in our heads, or use basically any method that gets our breathing to less than 10 breaths a minute to get positive outcomes.

 

(Note: I put 6 to <10 breaths/min in the 1 Big Takeaway because that’s what the study showed.  But it seems likely that any comfortable slow breathing rate between 3-10 breaths/min will work.) 

 

Thus, to apply this study’s findings, perform slow breathing at a comfortable pace of less than 10 breaths/min for at least 10 minutes a day for ~4 weeks. 

 

If you’re unsure where to start, 6 breaths/min is usually the best place: Inhale for 4 seconds, exhale for 6.  Count in your head or use this app.

 

Enjoy improving your cardiovascular and autonomic health with this simple practice.