Scientists Map Human Heart in Real Time During Freediving

Jerusalem, 5 February, 2026 (TPS-IL) -- (Adnkronos) – A collaboration between the Institute of Clinical Physiology (IFC) of the National Research Council (CNR) and the Sant’Anna School of Advanced Studies in Pisa, thanks to a special technology, has made it possible to map the reactions of the human heart during free-diving.

Underwater, humans and marine mammals resemble each other. A pioneering collaboration between the Institute of Clinical Physiology (IFC) of the National Research Council (CNR) and the Sant’Anna School of Advanced Studies in Pisa, using special technology developed in 2005, has allowed them to map the reactions of the human heart during free-diving . This has provided key insights into diseases such as acute pulmonary edema.

The Diving Suit

It’s called “Betar Asfar” — Arabic for ‘yellow thing” — the innovation that, over twenty years of research, has revealed the secrets of the heart in the deep. It’s a special diving suit, according to a press release, capable of housing a portable echocardiograph like those used in medical clinics. Designed by engineer Remo Bedini of the National Research Council (CNR) in Pisa, the device allows for recording echocardiographic examinations up to 20 meters deep, using a protruding ultrasound probe and a waterproof glove that allows the diving doctor to set the ultrasound parameters during the dive.

Previous studies were based exclusively on data collected before and after dives, but the new system has revolutionized research by allowing for live observation of the heartbeats of divers and freedivers, considered the most significant physiological model. Following testing in the Cascina nel Pisano swimming pool, the diving suit was used to study champions such as Umberto Pelizzari and after travelling all over the world, from Sharm El Sheikh to Brussels, it found an ideal scientific laboratory in Y-40 The Deep Joy in Montegrotto Terme (Padua).

“By inserting the echocardiographic instrument into this suit,” explains Claudio Marabotti, part of the operational research team and professor of the 2nd level Master’s Degree in Underwater and Hyperbaric Medicine ‘Piergiorgio Data’ organized by the Scuola Sant’Anna in collaboration with CNR-IFC, “we can obtain moving images of the heart, information on blood flow and the physiology of the heart while underwater , something that had never been possible before. We have been coming to Y-40 for 10 years to use it because it is an ideal place for research for several reasons: the standardization of the underwater environmental conditions that make our body’s physiological responses reproducible; the logistics, being easily accessible; and the hauling of the suit, which is very heavy, using the available winch. Aside from teaching activities, we use this instrument for research purposes.”

Data and Results

The data collected thanks to Betar Asfar show that, “although with profoundly different aspects,” the researchers report, ” the human heart reacts similarly to that of marine mammals during diving, with a slowing of the heart rate and a significant reduction in circulation. The same data also highlighted the onset of a “restrictive” functional pattern in the left ventricle, caused primarily by two mechanical factors: the environmental pressure compressing the chest and the “blood-shift” phenomenon, or the movement of blood from the periphery to the thoracic vessels.

That hypothesis was confirmed by a crucial experiment: by allowing divers to take a single breath from a regulator at depth, the chest volume returned to normal and the cardiac alterations disappeared instantly.”

For the scientists, “the collected results also scientifically explain the onset of acute pulmonary edema in ‘super-healthy’ subjects like some elite freedivers: the restriction of the left ventricle impedes the flow of blood from the lungs to the heart, causing congestion of the pulmonary capillaries. This mechanical stress, combined with the reduction in oxygenation, can cause the capillary walls to rupture and the resulting extravasation of fluid or blood into the alveoli, a condition that has also proven problematic in past world record attempts.” Marabotti explains: “To better visualize the research concept, you can think of the freediver’s heart as a sponge inside a compressed box. As the external pressure tightens the box (the chest), the sponge (the heart) can no longer fully expand to collect the fluid (the blood), creating a ‘traffic jam’ in the tubes leading to it (the lungs).”

Not just research at Y-40 Open Lab, which recently hosted—as reported in the press release—the ‘Piergiorgio Data’ Master’s course, directed by Vincenzo Lionetti, associate professor of Anesthesiology at the ‘Health Science’ Interdisciplinary Research Center of the Scuola Superiore Sant’Anna, for three days of freediving and self-contained breathing apparatus practice. The days celebrated 10 years of collaboration with Y-40 and the 20th anniversary of the Master’s course in Pisa.

With its two-year program, students develop advanced skills in underwater echocardiography, under the guidance of Marabotti and Alessandro Pingitore; to test themselves with BLS and automated external defibrillator sessions in emergency scenarios, coordinated by ESA (Eco Scuba Agency) general manager Mario Romor; to practice freediving and equalization techniques with instructor Giovanni Bianco, and to practice prevention, rescue, and recovery procedures in open and confined waters. The operational team includes experts such as Alessandro Scalzini and Ferruccio Chiesa, Marco Laurino (Cnr-Ifc scientific director for the Master’s activities), supported by diving operators Mirko Passera, Fabio Brucini, Danilo Cialoni and Chiara Benvenuti.

“In recent years,” Lionetti concludes, “the information gathered on the anatomy and function of the heart while humans are freely immersed has been described and published in top-tier scientific journals, cementing the ‘Piergiorgio Data’ Master’s Degree in Underwater and Hyperbaric Medicine as an international benchmark of excellence for those working in extreme environments or treating conditions such as carbon monoxide poisoning.”