Diving After Decompression Sickness: Waiting Times and Medical Checks

Is there a standard waiting time after decompression sickness?

No. Every published interval is a judgement, not a measured safe period. The 2011 UHMS best practice guidelines say there is no compelling evidence to support any specific waiting period after treatment of DCS. DMAC, which writes guidance for commercial divers, says return-to-diving guidance rests mainly on the policies of large organisations rather than a solid scientific basis. A 2024 review by Simon Mitchell in Diving and Hyperbaric Medicine states there are no evidence-based guidelines.

The sources agree on the order of steps: full recovery, a review by a doctor trained in diving medicine, then a return, possibly with limits. Older texts and the US Navy call mild pain and skin cases Type I and neurological cases Type II, a boundary the 2024 review calls ill-defined.

If you have symptoms now, or old ones have come back, call local emergency services, then DAN's 24-hour emergency hotline on +1-919-684-9111 (DAN Europe: +39 0642115685), and follow our guide to decompression sickness symptoms and first aid. This article summarises published guidance and is not medical advice. More health topics are in our safety guides.

How long to wait after DCS: what each source says

The shortest published interval is 24 hours and the longest six months, both from one commercial diving guideline. Recreational advice sits at the longer end: DAN Southern Africa calls the US Navy's old rule of 48 symptom-free hours after quickly resolved pain-only DCS probably a little too aggressive for recreational divers, who may go straight back to several days of repetitive dives.

Three disagreements stand out. For pain-only DCS, the figures are 24 hours under ADCI, 7 days under DMAC and the Navy, at least 2 weeks from DAN and a month in the popular recommendation the 2024 review cites. For severe neurological DCS, DAN says do not return, while DMAC finds insufficient evidence to disqualify a diver who has recovered completely and allows a return after 3 months. DAN has also published two sets of numbers: 2 weeks for pain-only DCS on dan.org, and 2-4 weeks in a 2016 DAN Southern Africa answer.

What the dive medicine review checks before you go back

The review checks whether diving again makes sense, not only whether enough days have passed. The 2024 review names three criteria doctors frequently apply: a full recovery, no suspicion that lung overexpansion (pulmonary barotrauma) was involved, and no pattern pointing to a predisposition, such as shunt-type DCS after a dive that should not have caused it.

Who reviews you depends on where you dive. The UKDMC wants one of its medical referees to examine the case, with information from the treating physician. DMAC requires written clearance from a diving medicine specialist for neurological cases, and a specialist review for anyone who has had DCI before.

Chris Acott suggested reviews at one week to catch a treatable relapse, at four or six weeks to decide on a return, and at one year, because in one study 6 of 12 treated divers who were neurologically normal at discharge had overt neuropsychological problems a year later. Bring these to the appointment:

• Computer profiles of the incident dives and the days before; the UKDMC assessment starts with a precise dive history.
• Treatment records: tables used, number of sessions and how fast symptoms cleared. Elliott says how well treatment worked matters more than which table was used.
• Any relapse, new symptom or leftover problem since treatment.
• Earlier episodes of DCS, even mild ones. DAN says repeated episodes need special consideration.
• Results of any MRI, shunt test or lung scan already done.

Residual symptoms: aches, fatigue and deficits that do not clear

Not everyone leaves the chamber fully recovered. DAN Southern Africa puts immediate and complete recovery at 70% of injured divers. The other 30% have partial or temporary relief, and most mild leftovers, often due to inflammation, fade over a few days to a few weeks.

Some symptoms are expected. The 2024 review says fleeting aches where the pain was are common after treatment for joint or muscle pain and usually need no more recompression, and fatigue is common too. Ease back into exercise, because hard exercise can bring on symptoms that feel like a relapse, and report any relapse of significant symptoms.

Symptoms that persist get more treatment first. The US Navy manual allows further chamber sessions, which can still help after a delay of up to a week, and stops once two in a row bring no sustained improvement. Joint pain that will not settle is occasionally a bone infarct (a blocked blood supply to part of a bone), and DAN Southern Africa says further diving is usually not recommended if the joint is involved.

For neurological leftovers the sources mostly agree. The UHMS guidance for physicians lists serious brain, spinal or inner ear DCS with residual deficits, and any history of inner ear (vestibular) DCS, as severe risk conditions. DAN and ADCI advise against diving with residual symptoms; DMAC allows a case-by-case decision, usually after at least 3 months. The reason, according to the 2024 review, is reserve: a damaged nervous system may lose more function in a second episode.

When a PFO test comes before diving again

After some types of DCS, a test for a heart shunt is part of the return. The 2025 SPUMS/UKDMC joint position statement says testing should be considered after cerebral, spinal, inner ear, cardiovascular or skin DCS. Joint pain alone is not on that list. The test and the options after a positive result are in our guide to PFO and scuba diving.

Older guidance is narrower. The UHMS 2011 guidelines call PFO testing not indicated after pain-only DCS and an option in selected patients with severe or repeated neurological DCS. For Navy divers, Type II DCS after a no-decompression dive, or a second Type II episode, triggers a PFO evaluation, and a PFO found that way is disqualifying unless waived.

A negative test does not clear you. Druelle and colleagues describe a diver with a negative shunt test after a spinal bend who was cleared, kept diving the same way and had a second spinal DCS; three months later he could walk only a few metres with crutches. They recommend a spinal MRI too, to look for narrowing that could press on the cord.

Repeated or "undeserved" DCS

A second episode, or a first one after a dive that should not have caused it, changes the advice more than the waiting time. DAN says divers who have had DCI more than once need special consideration even if every episode was mild, and that getting DCI on profiles other divers complete without problems may mean higher susceptibility, a case for a dive medicine specialist.

Elliott drew the same line. A deserved bend follows a problem such as running out of air and missing stops, and better dive management can prevent a repeat. An unexpected one follows a safe dive on accepted tables and suggests susceptibility. If it was neurological, especially a second such episode, he advised considering an echocardiogram for a PFO. The UKDMC says shunt and lung tests are often needed, particularly when the incident happened within the tables.

Acott's 1996 view was stricter: a recreational diver with neurological symptoms after a seemingly trivial exposure, or a second episode with no apparent cause, should be advised to stop diving. The 2024 review takes a softer line: investigate, then weigh PFO closure, more conservative diving or stopping, knowing recurrence is always possible.

Flying after recompression treatment

Wait at least 72 hours after treatment if every symptom has gone: that is the minimum in the US Navy Diving Manual and the UHMS 2011 guidelines. With residual symptoms, the Navy allows flying only when a diving medical officer agrees. DAN's chamber network FAQ adds that longer waits are routinely prescribed in the Asia-Pacific region, and that residual symptoms may mean waiting a week or more.

The data behind any number are thin. In a 2004 survey of US hyperbaric facilities cited by the 2024 review, median advice was 3 days after mild DCS (range 1-7) and 5 days after serious DCS (range 2-7), yet three divers who relapsed in flight had waited 14 hours, 3 days and 10 days. In DAN's online survey of 310 treated divers, only a quarter had been given a specific wait, and the advice ranged between 15 hours and 90 days. DAN reports that UK chambers in 2005 advised between no delay and 6 weeks.

Full recovery matters more than the hours. In an observational study cited in the 2024 review, whether symptoms had fully resolved before the flight predicted relapse in the air better than the length of the wait. The review's examples: about 3 days after mild DCS that cleared quickly and completely on the first treatment, at least a week for leg weakness that was slow to respond. For ordinary dives, see our guide to flying after diving.

How to dive more conservatively when you return

Changing how you dive has the clearest link to fewer repeat episodes. In a French case-control study of recreational divers treated for neurological DCS, those who kept diving the same way after the first episode had 8.4 times the odds of a second, and a large shunt raised the odds 5.4 times. A German study of 27 divers advised to dive more conservatively after DCS counted 34 episodes in 17,851 dives before the advice and 4 in 9,236 after it, with or without a shunt. Both studies are small and retrospective.

The measures below come from the 2025 SPUMS/UKDMC statement (written for divers with a shunt), the 2024 spinal DCS paper (which applies them to divers without one) and Elliott's article. Your diving doctor may set different limits.

• Keep dive times well inside the no-decompression limit; skip dives that need decompression stops.
• Stay shallower. SPUMS/UKDMC say dives deeper than 15 m (49 ft) raise the risk of shunt-related DCS; the 2024 paper suggests no deeper than 30 m (98 ft).
• Make fewer dives: one a day in the SPUMS/UKDMC statement, no repetitive dives in the 2024 paper. Build depth and time up gradually on a multi-day trip.
• Lengthen the safety stop or shallow stops on purpose.
• Breathe nitrox but plan with air limits. The 2024 paper stresses that nitrox lowers the risk only if you keep to air limits.
• Make your computer more conservative. Elliott suggested cutting no-stop times by going "one down" on the tables or switching a computer to altitude mode at sea level. On a gradient factor computer, DAN's Neal Pollock describes 30/70 as a bigger buffer than 15/85.
• Keep effort low on the dive. Afterwards, avoid heavy exercise, lifting, straining and forceful Valsalva manoeuvres for at least 3 hours (SPUMS/UKDMC). The 2024 paper adds no strenuous effort for 6 hours and no breath-hold diving straight after a scuba dive.

Worked example: nitrox on air limits at 18 m

Say you are cleared for no-decompression dives and plan 18 m (60 ft) on EAN32. On the DECO 2000 air table, the no-decompression limit at 18 m is 45 minutes. Our nitrox calculator gives an equivalent air depth of 14.2 m for EAN32 at 18 m, rounded up. The table rounds depth up to the next row, so a diver using nitrox limits would read the 15 m row: 72 minutes.

On air limits, 45 minutes stays the ceiling, and staying well inside it means a shorter dive. Your nitrogen uptake matches an air dive about 4 m shallower than the one the limit assumes, and that gap becomes margin instead of bottom time. The oxygen partial pressure is 0.90 bar, under the 1.4 bar working limit, and the maximum operating depth of EAN32 at 1.4 bar is 33.7 m.

Set the computer to the mix you actually breathe. Pollock warns that setting it to air while breathing nitrox removes its warnings about oxygen exposure, so add margin through the conservatism setting and your own plan. Our tools are planning aids and do not replace training, a dive computer or your doctor's limits.