The simple answer is; you shouldn’t feel tired after diving.
If you find yourself inexplicably fatigued, malaised or sleepy after diving then it can be due to ‘decompression stress’.
Don’t dismiss these sensations as “normal”, and don’t rush to assume they’re due to either cold or exertion on a dive. Cold baths don’t make you sleepy and nor does vigorous exercise.
Decompression stress is theorized to be a physiological effect that stems from micro-bubbles that can form in the blood and tissues as a result of sub-optimal dive behaviours.
The micro-bubbles, whilst essentially harmless in themselves (at that small size, and not on a frequent basis), are believed to trigger an immune response in the body. The tail-end of that immune system cascade (complement system) includes the release of histamine and then serotonin into the body. Those, in turn, can make you feel tired and sleepy. The same bubbles may also affect the endothelium layer of blood vessels, causing complications that have the same result.
Solutions to stop feeling tired after diving
- Actively hydrate before and after diving.
- Use nitrox: it helps prevent and eliminate micro-bubbles on the ascent.
- Maintain consistent depth and avoid continual buoyancy fluctuations, especially on shallower dives.
- Don’t conduct yo-yo or saw-toothed profile dives.
- Ascend at the optimal speed (9m/30′ per min). Definitely don’t ascend faster; but also avoid crawling up to the surface at a slower speed.
- Conduct safety stops with accurate buoyancy: control your depth within 50cm/1.5ft, but aim for half that deviation.
- Add additional safety stops – above and below the traditional 5m/3min stop. Consider also spending a minute at 9m/30ft and a few extra minutes at 3m/10ft.
- Ascend very slowly from your last stop at no greater speed than 3m/10ft a minute. i.e. take 1–2 minutes between the safety stop and the surface.
- Conduct lengthy surface intervals – at least one-hour duration, but ideally longer.
- Minimize repetitive diving on a single day.
Quite often, divers with inconsistent fundamental skills notice problems that could be decompression stress. More skilled divers do not. That should be a good motivation to consider spending some time doing dedicated practice and improving your buoyancy, trim and overall control in the water.
Here are some links to further reading on the points I’ve made:
The greatest variation between divers is the individual perception of susceptibility to narcosis. This is the person's awareness of when, or if, they are suffering a decline in mental cognizance due to elevated nitrogen partial pressure.
A new study on nitrogen narcosis challenges the long held presumption that nitrogen narcosis impairment dissipates immediately on ascent from depth.
The commonly taught model of alcohol-like intoxication fails to describe the nuanced cognitive effect upon the diver and, at worst, promotes divers towards a dangerous misbelief that they aren't mentally impeded by narcosis
About the Author
Andy Davis is a RAID, PADI TecRec, ANDI, BSAC and SSI-qualified independent technical diving instructor who specializes in teaching sidemount, trimix and advanced wreck diving courses.
Currently residing in Subic Bay, Philippines; he has amassed more than 10,000 open circuit and CCR dives over 27 years of diving across the globe.
He has published numerous diving magazine articles, designed courses for dive training agencies and tests/reviews dive gear for scuba equipment manufacturers. He is currently writing a series of advanced diving books and creating a range of tech diving clothing and accessories.
Prior to becoming a professional technical diving educator in 2006, Andy was a commissioned officer in the Royal Air Force and has served in Iraq, Afghanistan, Belize and Cyprus.
Originally posted 2019-02-22 12:20:48.