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Citation

Bernardi NF, Bordino M, Bianchi L, Bernardi L. Acute fall and long-term rise in oxygen saturation in response to meditation. Psychophysiology. 2017 Dec;54(12):1951-1966. doi: 10.1111/psyp.12972. Epub 2017 Aug 25. PMID: 28840941.

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Note: You can share anything you want from these 411s—the more sharing the better. But this is my attempt to condense the findings into a bite-sized wisdom nugget:

A 2017 study in Psychophysiology found that mantra-based mindfulness reduces metabolism independently of breathing rate, whereas slow breathing increases heart rate variability independently of meditation. Combining them into one practice may provide the best of both techniques.

4 Fundamentals

1. Essential Background Material

Some common physiological effects of meditation are a reduced heart rate, decreased breathing rate, reduced blood pressure (all of which comprise a “hypometabolic state”), and improved heart rate variability in some cases.

A confounding factor for understanding these benefits is that meditation naturally slows down breathing rate. Hundreds of studies have found that slow breathing by itself can provide many of these same benefits: it lowers blood pressure, improves HRV, and decreases breathing rate.

Thus, it’s unclear if meditation’s physiological benefits are primarily due to slower breathing or if there are other changes elicited by meditation independent of breathing.

This study aimed to isolate meditation’s unique, acute physiological effects by controlling for breathing rate.

Additionally, it examined if long-term meditation practice elicits favorable cardiorespiratory changes.

Nick’s Note: Although unintentional and not explicitly stated, they uncover a significant benefit of combining mindfulness with slow breathing to amplify both of their benefits.

2. What Did this Research Do?

There were 80 participants in this study. Forty-one participants had prior meditation experience (“meditators”), and 39 did not (“controls”).

The participants performed seven different protocols while lying on their backs with their eyes closed:

1. Initial Baseline [4 min]

2. Paced Breathing at 15 Breaths a Minute (equal inhale:exhale) [5 min]

3. Paced Breathing at 6 Breaths a Minute (equal inhale:exhale) [5 min]

4. Mantra Meditation while Breathing at 15 Breaths a Minute [5 min]

5. Mantra Meditation while Breathing at 6 Breaths a Minute [5 min]

6. Body Scan Meditation (observing right hand & index finger specifically) [5 min]

7. Final Baseline [4 min]

The paced breathing exercise (#2 and #3) were randomized. The meditation exercises (#4, #5, #6) were also randomized.

The mantra involved silently focusing on and repeating a single word that was meaningful to them. This is almost identical to Herbert Benson’s suggestion for eliciting the relaxation response (see Book 411 here).

3 & 4. What Were the Major Findings and Why Do They Matter?

The addition of the mantra-based mindfulness reduced breathing volume and heart rate independent of breathing rate (this is the most important finding from the study, in my opinion).

The addition of meditation reduced oxygen saturation, tidal volume, minute ventilation, and an indirect measurement of chemosensitivity (urge to breathe) compared to breathing alone. For example, breathing at 6 breaths/min with meditation significantly reduced oxygen saturation compared to 6 breaths/min without meditation.

These results are significant for two reasons. First, they uniquely show that the hypometabolic effects of meditation occur independently of breathing rate.

Second (this is my personal addition, not mentioned in the paper), the only contraindication of slow breathing is that people tend to hyperventilate when learning it (the slow breathing rate is challenging, so they overcompensate by breathing more).

These results show that, in both experienced meditators and new practitioners, adding a mantra to the slow breathing practice reduces the tendency to overbreathe. Thus, this could be a significant complement to a slow breathing practice.

Slow breathing increased heart rate variability independent of meditation.

Perhaps unsurprising given all the research on slow breathing and HRV, but it’s still important to note that slow breathing provided benefits independent of meditation.

Long-term meditation practice may produce (in the authors’ words) a “rather optimal cardiorespiratory function.”

At baseline, the meditators generally had lower blood pressure, a lower breathing rate, and greater brain and tissue oxygenation than the controls. As stated above, the practice of meditation acutely dropped oxygenation. This indicates that, over time, the acute drop in oxygenation during meditation trains the body to run more efficiently. This would explain why meditators generally had a lower breathing rate and blood pressure but still had greater oxygenation.

Altogether (this is my interpretation), we could say: Mindfulness amplifies the benefits of slow breathing. Slow breathing amplifies the benefits of mindfulness.

In my opinion, the two practices (slow breathing and mantra-based mindfulness) complement each other perfectly. Combining the two into one practice (like they did here) seems like an excellent way to get slow breathing’s HRV and nervous system benefits and meditation’s metabolism benefits.

1 Big Takeaway

Mantra-based mindfulness reduces metabolism independently of breathing rate, whereas slow breathing increases heart rate variability independently of meditation. Combining them into one practice may provide the best of both techniques.

1 Practical Application

Choose a meaningful focus word or phrase (see Thought # 2 in this Book 411 for more instructions). Then, place your attention on your focus word/phrase for the duration of your slow breathing practice to naturally reduce breathing volume and improve chemosensitivity. If you’re an instructor, this approach may be helpful with clients learning slow breathing.