Darnold9999
Contributor
Slow ascent makes a huge difference for me. The last 15 feet seems to make the most difference for me. Finish the safety stop and then up 1 foot at a time until the waves get in the way seems to make a huge difference.
Tired after diving
- Thread starter philliplehman
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We have a local pond we dive at that has a long swim each way at 17 feet or so before getting to a boulder strewn slope off of an island. When we dive there we bring 1/2 liter bottles of drinking water in our pockets and stop for a drink before heading back, these dives have run times of 120 - 150 minutes.
Pete
Pete
Charlie99
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Underwater. The Capri Sun comes in flexible foil packs that collapse as you drink them and work nicely underwater. They are only 5 or 6 ounces and store nicely in my BCD until needed. The only drawback is that they aren't resealable and unlike a camelback sort of device, you need to drink the entire juice pack in a short period to avoid getting water into it. Salty juice isn't one of my favorites.
I do find that even this small drink of sugar and water is nice after breathing dry scuba air for an hour.
Saturation
Medical Moderator
The most common cause of fatigue after recreational diving is cold exposure and exertion.
It may also be a pre-DCS state caused by inert gas loads.
Most technically trained divers feel the reverse after diving, properly geared, gases and off gassed, they are often energized. They dive for an extensive duration then remain very active once surfaced.
Fly Girl
Contributor
I am a total newbie, so please, just take this for what it is worth, which may not be much. I started out diving on air. I was totally bone tired exhausted when I finished my dives. Since I got NITROX certified and have started using NITROX, I feel so energized after my dives. Once again, it could just be that I'm diving better, and it could all be in my head, but darn, I sure feel great after diving, and it seems like this feeling came when I started NITROX. (please don't flame me if I'm way off, but if I'm giving incorrect thoughts, don't hesitate to let me know.)
Tigerman
Contributor
My ascents is usually quite slow - as much so that guides has kept giving me the surface thumb during my ascents - and I (try to) avoid profiles thats got lots of ascents and descents, but im still tired (but not fatigued) after diving. Im also running straight to the bathroom after all my dives peeing silver as I just CANT pee in a suit as most my diving is in drysuit and when I do dive wet i just cant make it. I blame the nitrogen and the fact that I relax far more under water than I normally do on land 
Before I moved here I stayed on my boat on weekends and dove a lot - 3-4 dives per day over a three day weekend was not uncommon and they tended to run deep with at least half well below 100 feet, and to make it even more fun, they were at an altitude of about 4000'.
When I first started doing this I would feel positively flu like on Monday morning even though I stayed within the table and computer limits on all the dives and used the standard 30 fpm ascent rate. Obviously that was not working.
I started doing deep stops and slow ascents (an average ascent = deep stop at half max depth - say for example 65 ft - with a 10-20 ft per minute ascent from there, 1 minutes stops at 40', 30' and a 3 minute stop at 20' followed by a slow and gradual ascent to the surface. When ever possible (wall dives etc) I'd also end the dive with a nice long swim between 15 and 30 ft. usually working my way up from 30' very slowly.
That did the trick and eliminated the fatigue, the flu like symptoms and the body aches.
Shortly after that I got into technical diving and started doing deco dives on most of the deep dives with 25% or 26% Nitrox and using 50% Nitrox for a deco gas using a bubble gradient deco model (DPlan) or a variable permeability model (Palm-VPM). Both tend to be more conservative than the average haldane model and the 50% is much more efficient for deco. The average dive would then be 130-150 for around 20-30 minutes with deco stops starting at 70' with 50% with slow ascents and fairly short 1-3 minute stops every 10' ending with about a 5 minute stop at 20' and a 7-10 minute stop at 10' with a run time around 45-50 minutes. And again even with the
deco, I always felt great afterwards and on Monday morning.
Decompression theory is just that - theory. If your body is telling you that what your computer is telling you is "ok" is not working, then ascending slower with a deep stop and a longer safety stop may be in order.
I also agree that Nitrox probably helps - if you are using it on an air table to increase safety. If you are diving it to the NDL for the particular nitrox mix and or are going into deco with it, then I don't think it will make much difference and you will be back to relying on slow ascents, deep stops, longer safety stops and no saw tooth profiles.
The idea behind deep stops and slow ascents (and avoiding saw tooth profiles) is to off gas a little deeper and avoiding bubble formation as it is more efficient to off gas prior to bubble formation than it is to try to off gas once those small "silent" bubbles have formed during a 30-60fpm ascent to a shallow safety stop depth.
Once on the surface, don't exert your self right away. Float around on the surface for 5 minutes or so, relax and continue off gassing a bit before excercising a lot climbing the bank, stairs, or walking back to the car. Or, if you have to get on the boat right away, extend your safety stop a minute or two more on the hang line, then get on the boat and just sit there for 5 minuites or so before you start taking off all your stuff.
Hydration is also extremely important and in fact I'd say it is probably the number 1 pre-disposing factor for DCS. Drinking alcohol the night before a dive is a great way to get dehydrated and increase your risk of DCS. Same with coffee or caffinated beverages - it takes a lot of water to remove the caffine from your system.
My preference is just plain water most of the time with maybe the occasional sports drink or decaffinated green tea/iced tea. I start the day before and ensure I am well hydrated and then maintain that state rather than try to force fluids the day of the dive.
Dry suits can be problematic if you do not have a pee valve installed (or are female and not She-P or depends inclined) if it means you stop drinking water out of fear of needing to pee during a dive. A little salt, as in eating a small bag of potato chips a bit before the dive can help avoid the need to pee during the dive.
When I first started doing this I would feel positively flu like on Monday morning even though I stayed within the table and computer limits on all the dives and used the standard 30 fpm ascent rate. Obviously that was not working.
I started doing deep stops and slow ascents (an average ascent = deep stop at half max depth - say for example 65 ft - with a 10-20 ft per minute ascent from there, 1 minutes stops at 40', 30' and a 3 minute stop at 20' followed by a slow and gradual ascent to the surface. When ever possible (wall dives etc) I'd also end the dive with a nice long swim between 15 and 30 ft. usually working my way up from 30' very slowly.
That did the trick and eliminated the fatigue, the flu like symptoms and the body aches.
Shortly after that I got into technical diving and started doing deco dives on most of the deep dives with 25% or 26% Nitrox and using 50% Nitrox for a deco gas using a bubble gradient deco model (DPlan) or a variable permeability model (Palm-VPM). Both tend to be more conservative than the average haldane model and the 50% is much more efficient for deco. The average dive would then be 130-150 for around 20-30 minutes with deco stops starting at 70' with 50% with slow ascents and fairly short 1-3 minute stops every 10' ending with about a 5 minute stop at 20' and a 7-10 minute stop at 10' with a run time around 45-50 minutes. And again even with the
deco, I always felt great afterwards and on Monday morning.
Decompression theory is just that - theory. If your body is telling you that what your computer is telling you is "ok" is not working, then ascending slower with a deep stop and a longer safety stop may be in order.
I also agree that Nitrox probably helps - if you are using it on an air table to increase safety. If you are diving it to the NDL for the particular nitrox mix and or are going into deco with it, then I don't think it will make much difference and you will be back to relying on slow ascents, deep stops, longer safety stops and no saw tooth profiles.
The idea behind deep stops and slow ascents (and avoiding saw tooth profiles) is to off gas a little deeper and avoiding bubble formation as it is more efficient to off gas prior to bubble formation than it is to try to off gas once those small "silent" bubbles have formed during a 30-60fpm ascent to a shallow safety stop depth.
Once on the surface, don't exert your self right away. Float around on the surface for 5 minutes or so, relax and continue off gassing a bit before excercising a lot climbing the bank, stairs, or walking back to the car. Or, if you have to get on the boat right away, extend your safety stop a minute or two more on the hang line, then get on the boat and just sit there for 5 minuites or so before you start taking off all your stuff.
Hydration is also extremely important and in fact I'd say it is probably the number 1 pre-disposing factor for DCS. Drinking alcohol the night before a dive is a great way to get dehydrated and increase your risk of DCS. Same with coffee or caffinated beverages - it takes a lot of water to remove the caffine from your system.
My preference is just plain water most of the time with maybe the occasional sports drink or decaffinated green tea/iced tea. I start the day before and ensure I am well hydrated and then maintain that state rather than try to force fluids the day of the dive.
Dry suits can be problematic if you do not have a pee valve installed (or are female and not She-P or depends inclined) if it means you stop drinking water out of fear of needing to pee during a dive. A little salt, as in eating a small bag of potato chips a bit before the dive can help avoid the need to pee during the dive.
Keith & Sharon
Contributor
Excellent thread with great information for the next dive (tomorrow). Typically dive Nitrox with air profile and feel great, but when I dive air, I'm always tired afterwards. Thanks to everyone that posted. I will definitely pay more attention to a much slower ascent.
OP
philliplehman
Registered
I will try the deep stops on all my dives, I would only do them on deco dives deeper than 30mtrs but I will now do them on all my dives. Unfortunately for me though sawtooth profiles are inevitable in some of the caves here with some real yoyo depth profiles. I will treat every dive even shallow no deco dives as needing longer stops etc.. I think from what you guys are saying it will help allot. Thanks
IMO, "tiredness" relates to muscle fatigue and sleepiness. My guess of the situation is this:
Skeletal muscle fatigue is associated with increased cellular acidity. For divers, increased partial pressures and decreased temperatures likely form a double-whammy. While increased oxygen partial pressure PO2 is beneficial (related to the Haldane effect of increased PO2 encouraging release of CO2), the flip side is increased PCO2. This may reduce the pressure differential needed for diffusion out-gassing of CO2. Also, a higher acid load is encouraged by cooler temps since these increase CO2 solubility in the blood. (Lower temps not only coming from skin exposure but also from the breathing gas being cooled in the exposed scuba tank.)
Maintaining acid-base balance are jobs for the lungs as respiratory compensation and the kidneys as metabolic compensation. Respiratory compensation is fast-acting, usually measured in minutes. But this efficiency may be impaired by the higher PCO2 and higher blood acid load from cooler temps. Metabolic compensation is much slower acting, taking hours. One key to convert acids to CO2 is the bicarbonate ion HCO3- which is a product of kidney function. Once the available stores of HCO3- are used up, the kidneys likely have to play catch-up. The delay in doing this means acid buildup and muscle tiredness persisting for awhile.
As for sleepiness, my guess would be that it's a reaction by the hypothalamus to increased acid levels. The result may be depression of the arousal system (reticular activating system) which serves to inhibit further activity to avoid adding to the acid load. In a ghoulish way, this aligns with the claims of tiredness by the dying -- acidosis is one leg of the death spiral triad; hypothermia and coagulopathy are the other two.
I can't really think of a quick reason to account for the reported benefits of a longer, slower ascent. Nor is it clear to me why a sawtooth profile seems to have worse effects than a simple bounce
Skeletal muscle fatigue is associated with increased cellular acidity. For divers, increased partial pressures and decreased temperatures likely form a double-whammy. While increased oxygen partial pressure PO2 is beneficial (related to the Haldane effect of increased PO2 encouraging release of CO2), the flip side is increased PCO2. This may reduce the pressure differential needed for diffusion out-gassing of CO2. Also, a higher acid load is encouraged by cooler temps since these increase CO2 solubility in the blood. (Lower temps not only coming from skin exposure but also from the breathing gas being cooled in the exposed scuba tank.)
Maintaining acid-base balance are jobs for the lungs as respiratory compensation and the kidneys as metabolic compensation. Respiratory compensation is fast-acting, usually measured in minutes. But this efficiency may be impaired by the higher PCO2 and higher blood acid load from cooler temps. Metabolic compensation is much slower acting, taking hours. One key to convert acids to CO2 is the bicarbonate ion HCO3- which is a product of kidney function. Once the available stores of HCO3- are used up, the kidneys likely have to play catch-up. The delay in doing this means acid buildup and muscle tiredness persisting for awhile.
As for sleepiness, my guess would be that it's a reaction by the hypothalamus to increased acid levels. The result may be depression of the arousal system (reticular activating system) which serves to inhibit further activity to avoid adding to the acid load. In a ghoulish way, this aligns with the claims of tiredness by the dying -- acidosis is one leg of the death spiral triad; hypothermia and coagulopathy are the other two.
I can't really think of a quick reason to account for the reported benefits of a longer, slower ascent. Nor is it clear to me why a sawtooth profile seems to have worse effects than a simple bounce
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