This practice trains recovery as a discipline: resonance breathing protocols timed to your evenings, objective HRV tracking to show what is changing, and a 10-week structure designed to make the skill durable. It is the same structure used in HRV biofeedback in NYC and in HRV training for athletes, where sleep is treated as a performance variable.

Why sleep and heart rhythm are linked.

Heart rate variability (HRV) is the small, constant change in time between heartbeats. It reflects how flexibly the nervous system shifts between effort and rest. When pressure stays high into the evening, many people carry a fast, steady heart rhythm into bed, and the body is still braced when the lights go out. HRV biofeedback teaches you to breathe at your resonance frequency, usually between about four and a half and six and a half breaths a minute, the pace at which heart rate, blood pressure and breath reinforce one another and HRV swings are largest. Practiced before bed, it is a way of rehearsing the downshift the body needs to make on its own.

What the training can do.

The research on slow breathing and HRV biofeedback for sleep is young but consistent in direction:

In a sleep laboratory study, adults with self-reported insomnia had lower high-frequency HRV than good sleepers. When they practiced slow paced breathing for 20 minutes before bed, they fell asleep sooner, woke less often and spent less time awake, measured by polysomnography (Tsai and colleagues, 2015).
In a randomized study of 64 healthy young adults, 15 minutes of app-paced slow breathing each evening for 30 days improved self-reported sleep quality and raised overnight cardiac vagal activity compared with 15 minutes of social media use (Laborde and colleagues, 2019).
In a crossover study of 14 highly trained male athletes with sleep disturbances, eight pre-sleep HRV biofeedback sessions over 15 days improved laboratory-measured sleep efficiency and reported sleep duration more than EEG biofeedback did, and only HRV biofeedback shortened reaction time (Li and colleagues, 2024).
A 2026 systematic review of nine studies (457 participants) found that self-reported sleep duration and quality improved after slow breathing before bedtime (Eide, Hernes and Grønli, 2026).

For most people the realistic aim is a reliable way to settle the body at night and a clearer picture, in their own data, of what helps and what disrupts their recovery.

What it cannot do.

Breathing training is not a treatment for sleep apnea, restless legs, or a sleep disorder that needs medical care. Loud snoring, gasping at night, or heavy daytime sleepiness despite enough time in bed are reasons to see a physician first. For chronic insomnia, cognitive behavioral therapy for insomnia (CBT-I) is the recommended first-line treatment. In a randomized study of 44 adults with insomnia disorder, adding HRV biofeedback to CBT-I did not significantly improve on CBT-I alone overall, though the combined group showed a unique gain in reported total sleep time (Lin and colleagues, 2026). HRV training is best seen as a complement to good sleep care, not a replacement for it.

Who it suits.

Executives and investors who travel. Time zones, late dinners and decisions that follow you to the hotel room make the evening downshift harder. Resonance breathing is portable, takes about 20 minutes, and needs only a phone and a heart rate sensor. See executive performance coaching.
Athletes. Training load, travel and competition nerves all show up in overnight HRV. Learning to downshift after evening sessions and before competition days is part of the athlete program. See HRV training for athletes.
Surgeons, clinicians and others on call or shift schedules. When sleep has to happen at irregular hours, a trained, repeatable way to lower arousal on demand is useful wherever and whenever the window opens.

What a program looks like.

Every engagement begins with a 55-minute consultation with Dr. Lagos, in person at 505 Park Avenue or remote. Training then follows the 10-week protocol:

A measured baseline. Your resting HRV and your resonance frequency are measured with a heart rate sensor and paced breathing at several rates, so the protocol is built on your physiology rather than a generic pace.
Weekly one-to-one sessions. Each session reviews your data, refines the breathing skill, and adds the next layer: physical release, attention, and using the skill under real pressure.
Home practice timed to your evenings. Short daily practice with a pacer at your rate, placed in the hour before bed where your schedule allows. In the published trials, nightly home practice mattered.
Wearable tracking. If you already use a wearable, it becomes a gauge. Together you read the trend in overnight HRV across weeks, and how travel, alcohol, late meals and workload move it, rather than reacting to any single morning's score.

What the research does not show.

Most studies are small, several were open-label, and many ran for a single night or a few weeks. Self-reported sleep improves more consistently than objective measures: in the 2026 review, results from actigraphy and polysomnography were inconclusive, and the authors called for longer, higher-quality trials. There is no evidence yet on how long benefits last after training stops, and individual responses vary. That is why the program measures your baseline and tracks your own response instead of promising a result.

For the research behind the protocol, see Dr. Lagos's published research. To discuss whether this training fits your sleep and schedule, request a consultation.

References.

Tsai HJ, Kuo TB, Lee GS, Yang CC. Efficacy of paced breathing for insomnia: enhances vagal activity and improves sleep quality. Psychophysiology. 2015;52(3):388-396. doi:10.1111/psyp.12333
Laborde S, Hosang T, Mosley E, Dosseville F. Influence of a 30-day slow-paced breathing intervention compared to social media use on subjective sleep quality and cardiac vagal activity. Journal of Clinical Medicine. 2019;8(2):193. doi:10.3390/jcm8020193
Li Q, Shi M, Steward CJ, Che K, Zhou Y. A comparison between pre-sleep heart rate variability biofeedback and electroencephalographic biofeedback training on sleep in national level athletes with sleep disturbances. Applied Psychophysiology and Biofeedback. 2024;49(1):115-124. doi:10.1007/s10484-023-09604-3
Eide EM, Hernes HM, Grønli J. Slow breathing techniques before bedtime and the effects on sleep: a systematic review. Sleep Medicine Reviews. 2026;87:102284. doi:10.1016/j.smrv.2026.102284
Lin YK, Huang YC, Huang WC, Lee HC, Lin IM, Yang CM. Can addressing autonomic hyperarousal with heart rate variability biofeedback enhance CBT-I outcomes in insomnia disorder? Behavioral Sleep Medicine. 2026;24(1):40-57. doi:10.1080/15402002.2025.2549554

Recovery is trainable.