On 14 May 2026, five Italian divers died in a deep cave system in Vaavu Atoll in the Maldives. There was subsequently much speculation about the exact circumstances of the accident. At the DAN Divers Days 2026, held in conjunction with the EUBS (European Baromedical Society) Congress in Geneva, we received detailed first-hand information for the first time from Laura Marroni, CEO of DAN Europe, who had also coordinated the international rescue operation. The accident: one las

Recent case reports, and in particular the MRI findings, raise an intriguing question: could what we refer to as cerebral DCS in freediving actually, in some cases, not be decompression sickness at all, but rather posterior reversible encephalopathy syndrome – or PRES for short (roughly translated as: a reversible brain disorder syndrome affecting the occipital region)? Taravana syndrome The term ‘Taravana’ originates from neurological incidents among the traditional mother-o

In scuba diving, the link between a patent foramen ovale (PFO) and decompression sickness is fairly well established. In freediving, however, we know surprisingly little. Nevertheless, there are intriguing indications that a PFO could play a role, particularly during deep and repetitive dives. But the picture is more complicated: perhaps some of what we have so far referred to as ‘cerebral DCS’ in freediving is not actually classic decompression sickness at all. And that is p

Hypercapnia is one of the most dangerous problems associated with rebreather diving. Elevated CO₂ levels can lead to shortness of breath, cognitive impairment and disorientation. At the same time, CO₂ increases oxygen exposure to the brain through enhanced cerebral blood flow, thereby potentially raising the risk of CNS oxygen toxicity. Added to this is the narcotic effect of CO₂, which can occur independently of nitrogen narcosis or be exacerbated by it. The real problem is

In recent years, the Mouthpiece Retaining Strap (MRS) has attracted increasing attention in rebreather diving. International organisations such as DAN and various rebreather training organisations now recommend the use of an MRS to reduce the risk of water aspiration in an unconscious diver. To illustrate the benefits of an MRS, DAN recently published an account from a CCR diver. The message is clear: the MRS may well have saved the diver’s life. The story is undoubtedly fasc

The recent publication of the large DAN analysis attracted considerable attention within the diving medicine community. The study analyzed more than 127,000 dives to identify risk factors for decompression sickness (DCS). Based on the results, the authors even propose an algorithm designed to calculate a diver’s individual DCS risk. Some of the identified factors seem quite plausible: higher decompression stress, longer dive times, or greater depths are, as expected, associat

Recently, a very experienced diving instructor asked me how useful the classic 3-minute safety stop actually still is from today’s perspective. It’s an intriguing question—because the 3-minute safety stop at 5 meters is practically standard practice in recreational diving today. It’s performed millions of times every year. Hardly any recreational dive during the holidays ends without the memorable rule: “Three minutes at five meters at the end of every dive.” Many dive comput

This story doesn’t begin underwater, but with a turning point that changes everything: the diagnosis of metastatic neuroendocrine carcinoma. From the very start, it’s clear that there will be no cure. From one moment to the next, daily life and routine are no longer the focus; instead, it’s all about treatments—and the question of what comes next. This article is based on the “Leben mit Metastasen” (“Living with Metastases”) campaign, in which Patricia, a doctor and diver, op

AI modified Saturday morning, 10:00 a.m. My buddy and I are doing a short technical dive to 60 meters. CCR, diluent 18/45. Planned bottom time: 15 minutes, followed by standard decompression. As we ascend from the depth, I notice that he starts gesturing. Shortly after, he ascends a bit faster than I’m used to seeing him do. We stay in contact, adjust our pace, and complete all planned decompression stops correctly. After a total of 55 minutes, we finish the dive without furt

I recently got into a discussion about diving on La Palma. The dive center there is located about 700 meters above sea level in the hills above the coast. El Hierro, the neighboring island, is ranked by DAN among the “top 6 most challenging dive sites” worldwide due to its similar topography. This raises the question for many: after a dive at sea level, isn’t there a significant risk of suffering decompression sickness during the subsequent ascent to the higher-altitude dive

A recent analysis of the DAN database has yielded a surprising result: women appear to have a significantly higher risk of decompression sickness (DCS) than men. The analysis is based on nearly 128,000 dives by approximately 5,900 divers. Overall, DCS was reported in about 0.49% of dives. In the data, DCS occurred about three times more frequently in women than in men; statistical modeling even yielded an odds ratio of 4.63—a more than fourfold higher risk for women! How is t

What began as my personal programming project is now available to everyone: Dekoplaner — a dive planner from Switzerland based on the Bühlmann ZHL-16C model, the globally established standard for decompression calculations. Dekoplaner deliberately focuses on the essentials: transparent and easy-to-understand calculations using classic gradient factors (GF low / GF high)—without unnecessary additional parameters. Dekoplaner is a powerful yet affordable all-rounder for planning

Anyone who dives using the Bühlmann model—which is practically all technically oriented divers using most modern computers—cannot avoid gradient factors (GF). But the question keeps coming up: Should no-decompression limit be calculated using GF low or GF high? This is where GF high plays a role. Foto: Karin Aggeler What does no-decompression limit actually mean? No-decompression limit means that during a dive, you can ascend directly from depth to the surface without exceedi

Case vignette: A 49-year-old, very experienced diver undertook a dive in a Swiss lake with his rebreather (JJ-CCR) in autumn. The water temperature was around 10 °C. After only about 10 minutes, he felt increasing shortness of breath, which rapidly worsened. After about 20 minutes, he had to abort the dive as an emergency. The diver had remained within no-decompression limits (maximum depth 30 m, O₂ set point 1.3 bar). At the surface, he was no longer able to remove his equip

From a medical point of view, helium is of little relevance outside of diving. Accordingly, its kinetics have been insufficiently studied in comparison to other inert gases used in medical research and diagnostics, for example as tracers (1). To date, the helium algorithms used in diving medicine are based predominantly on the data set published by Bühlmann. Foto: Karin Aggeler Helium in the Bühlmann model According to Bühlmann, the diffusion rate of helium is 2.65 times high

A 50-year-old diver went diving in a Swiss lake with his closed-circuit rebreather (CCR). The plan was to dive to a depth of around 55 meters with a bottom time of approximately 20 minutes (time until leaving the depth). Compressed air was used as the diluent, at a constant oxygen partial pressure of 1.3 bar. The last decompression stop was at 6 meters. The diver complied with all decompression requirements and ended the dive after a total of 54 minutes. However, about 30 min

An experienced recreational diver conducted a dive to a depth of 30 m in a Swiss lake within the no-decompression limit. During the ascent, he suddenly noticed impaired vision in his right eye. After surfacing, his vision was blurred and foggy in both eyes, whereupon he was given oxygen due to suspicion of a diving accident. After just ten minutes, his vision was completely restored. The diver reported having experienced similar problems with his right eye during previous div

NOAA guidelines for limiting oxygen toxicity in diving date back to the 1970s and 1980s – a time when rebreather technology, digital sensors and today's diving profiles were still a long way off. Nevertheless, these early, deliberately conservative values formed the basis of all safety guidelines for decades. With the current NOAA revision, these limits are now being fundamentally revised for the first time. The new recommendations on CNS oxygen toxicity take into account cur

I was recently asked by a diver whether it makes sense that his diving school requires him to undergo an echocardiography (heart ultrasound) before taking a technical diving course beyond Advanced Nitrox. The reasoning given was to check for a patent foramen ovale (PFO) — a small opening in the heart that, in theory, could allow bubbles to pass into the arterial circulation and increase the risk of decompression sickness. Lediwrack, Walensee. At first glance, this seems plaus

Recently, Croatian freediver Vitomir Maričić set a new world record in static apnea: he held his breath for 29 minutes and 3 seconds —a...