Hydration Strategies, Some More Musings From A Layman

[sandymere 8,263]

Hydration strategies

 

Drinking, dehydration and working dogs is a perennial subject that is both simple and complicated. In the simplest terms dogs need to drink but within the terms of a working dog staying hydrated whilst working it can become a little more complicated. Mammals have had a good few million years of evolution to hone their ability to maintain an appropriate fluid balance, as their fluid reserves reduce the electrolytes become more concentrated which alerts sensors that instigate thirst sensations. Seems a simple functional process so it might seem strange that dogs are becoming dehydrated? Perhaps the question needs to be what is having a negative effect on this process.

 

I was brought up on the belief that working dogs should be starved prior to work and water should be restricted during and for an hour afterwards. With the advances in both human and canine sports science this sort of attitude is being revaluated, of cause a dog will not perform as well if it has a very full stomach be it food or liquid but withholding food and water completely prior to or during work is no longer considered best practice. So dogs are likely getting access to water prior to work but is this enough? To answer that question it is easier to look in a little more detail at the processes involved to gain a better understanding.

 

Mammals have two main fluid compartments, one inside the cells, known as the Intracellular fluid (ICF) this is around 60 % of the total, the other is the Extracellular fluid which is outside of the cells (ECF) and makes up the remaining 40%, this includes the blood. The body controls these compartments and shifts fluid between them as needed. An example is that with exercise more fluid is pumped into the muscle cells, part of the ICF, from the ECF compartment due to increased solutes within the cells creating a higher concentration. With rest the fluid returns back to the ECF as the solutes between the two compartments equalise. This short term loss of volume from the external to the internal compartments during exercise shouldn’t be a problem unless it is extended for a long period and or there is significant loss of fluids via other routes.

 

If a larger loss occurs then problems will soon start to show. Even a minor state of true dehydration will effect performance and risk major problems like Rhabdomyolysis occurring. As the blood volume is reduced so the solutes within the blood, blood cells, electrolytes etc, become more concentrated causing imbalance between the two fluid compartments and problems with the muscle impulses, including the heart, whilst the heart has to work harder to pump the residual fluid faster to maintain blood pressure and perfuse the muscles. One would expect large losses with bleeding, diarrhea and vomiting but hopefully dogs suffering this type of problem wouldn’t be worked so where can losses be occurring?

 

It’s pretty much excepted that dogs don’t sweat to any great degree so sweating shouldn’t lead to any great fluid loss, urine is one route that will give fluid loss but this should be well covered by normal drinking so the question rises as to where fluid loss can be taking place? Breathing is one area that is often overlooked, breathing in either warm or cold conditions causes marked evaporation from the lungs and during extended exercise this can amount to an appreciable amount. But again this should be easily replaced with drinking. So there may well be a drop in volume through true loss via things like urination, breathing and through fluid transfer into the cells but the body is adapted to deal with this through increased cardiac output and drinking so again we are left with the question why are dogs getting dehydrated?

 

So we must go back to input if output is not the problem, drinking is the answer, all too often dogs aren’t given the opportunity to drink whilst working, I’ve seen dogs lamping for 3 or 4 hours without being offered the chance to replenish their water reserves. When questioned the owner’s state that they are worried drinking then running will cause various ills from twisted guts, vomiting and loss of performance. Of cause, as mentioned in the first paragraph, overloading the gut will have a negative impact but much as distance runners take on board small regular amounts of fluid during road races, dogs can take on small amounts of fluids whilst working without detriment to themselves or their performance. In fact rather than having a negative impact the opposite is more likely as reducing dehydration should enhance both performance, recovery and longer term health.

 

Another area is dogs spending extended periods traveling in cars or waiting for their opportunity to run, as already suggested panting cause’s fluid loss and if continued for any length of time this can be a substantial amount in respect of compromising the overall balance. A dog spending a couple of hours traveling then being expected to put in a shift of work is likely to suffer a degree of dehydration. It’s the same with dogs being left to await their turn whilst the owner is away lamping with another animal etc; the second shift starts with a risk of dehydration. It must be said that excited dogs may not wish to drink and one sitting in a car waiting excitably for its turn to get out working may well turn its nose up at water but the excited dog is exactly the one that would have been panting and so need the fluid. Adding something to the water can help to address this problem with glucose being a commonly used in this situation.

 

Using glucose/sugar water has the double effect of topping up glucose reserves as well as rehydrating but as this may well have an impact on blood sugar levels falling in the mid term, with this in mind it is perhaps something that is better continued once started. Small sips of the fluid regularly should help to maintain both hydration and blood glucose. Another down side is that high concentrations, above 6 % can cause stomach upsets as the body pulls in fluid to the digestive track to dilute the concentration it causes short term fluid loss to the rest of the body so mixtures should be made up carefully.

 

There are alternatives in the form of Maltodextrins, available as powders for self mixing or pre made energy drinks, this is a more complex form of sugar that can reduce the blood sugar highs whilst still giving good calories and as they have a lower osmolarity can be used to give good calories at low concentration ie 6%. Using the low concentrations reduces the tendency for temporary dehydration and the risk that the intestines may try to speed up clearance of the fluid causing stomach cramping or diarrhea. But in truth plain water is probably better with a maltrodextrin bar being used to maintain blood glucose levels rather than as an addition to the fluid, specialist energy bars are available for dogs although home made versions or general maltodextrin type energy bars are likely as good.

 

One area that has not been considered yet is pre loading, we’ve all heard of carb loading but the concept of fluid loading is less well known. Glycerol when added to water would seem to have the effect of making the body hold onto more of the fluid, basically causing it to load with water. This has been studied in sledge dogs and seems to have some value in long distance racing where dogs are unable to drink for long periods but my questions would be, excess fluid will mean excess weight which is likely to have its own draw back plus excess fluid would very likely increase blood pressure thereby putting extra strain on the hart when its working a full potential with a sprinting type animal at top speed. Lastly pulling a sledge for hours on end my have trouble getting access to fluid but a lurcher out lamping etc shouldn’t have that problem so loading would seem to have little real value in this case.

 

In conclusion lurchers shouldn’t be losing substantial amounts of fluids unless panting for long periods in which case get them to drink a sensible amount prior to starting. In general it’s perhaps best to maintain near normal levels with small regular sips/amounts rather than risk either over hydration or dehydration? Squirting a little water into a dogs mouth now and then from a water bottle whilst giving little pieces of an energy bar shouldn’t be to much of a trial on an owner if lamping for more than an hour or so after all you wouldn’t expect a footballer or athlete to compete without proper fluid and energy management so why should a lurcher? Of course dogs have run well without this type of intervention for many years but they might just run better and longer with it.

 

 

 

 

 

[socks 32,253]

I have for many years carried a small rose sprayer mixed 10% with recharge and a couple of squirts into the dogs mouth as and when needed does a world of good ... if you watch a sled dog race you will see the dogs frequently scooping up mouthfuls of snow to keep themselves hydrated .....

[sandymere 8,263]

There’s a few that give a squirt of fluid these days and hopefully it is a growing trend, I thought a topic on it would start a conversation around this in general. In truth I feel that what people often interpret as dehydration, dark urine etc, is in fact mild rabdo.

The Huskies are interesting, in that they, as you say, eat the snow but are still suffering dehydration, I imagine with the extreme cold the air is so dry the dehydration effect on the lungs and upper airways is perhaps more than is being replaced.

[sandymere 8,263]

Having looked at this it seems, sledge dogs are discouraged from eating snow on the run because it increases the risk of falls and unbalances the team, snow is mainly air having only about 5% water when new, air surrounding snow crystals, so they would need to eat a massive amount to gain any substantial amount of fluid and lastly it’s calorificaly wasteful for a body to warm ice.

 

 

 

There you go I learn something every day.

 

 

http://yukonquest.com/news/water-water-everywhere

Edited October 30, 2014 by sandymere

[socks 32,253]

It's the same as if you are in a cold climate area and you are trying to melt snow for fluids .... You need shovels full of the stuff to make a pan of water ... but also why it is so good at insulating if you make snow hole to keep out of the weather in .....

 

Edited to add .... The other thing about sled dogs is their ability to be fed a large meal just prior to running miles and never get gastric torsion .......

[beast 1,884]

i have found over the years that letting a dog have a few mouthfuls of water every now and then is very helpful. as you chaps have said, too much can cause problems but as a ball park figure, half a pint for a slightly dehydrated dog is very rapidly absorbed out of the gut system and into the tissues, so five or ten minutes after a small drink like that the dog is ready to go again. i have never found that extra sugar or such has made any difference to a dogs performance, you touched on carb loading and i think that diet is key to this point, a dog getting a good balanced diet, with plenty of fat when it is in hard work, should have no problems and shouldnt struggle to keep weight on over a long hard winter

[sandymere 8,263]

Indeed socks we often forget that the stomach is in itself an energy store where food/calories can are carried and used over a period of hours plus with husky types being fed a high fat diet that also is a source of fluid.

The carb loading is interesting Beast, dogs trained to sprint do carry greater amounts of glucose in their muscles compared to untrained individuals, not to the extent of humans. Basically training increases the dog’s ability to utilise fats whilst increasing glucose availability so it enhances both energy systems. The percentages of use seem to stay the same but total capability is enhanced. We think of muscle adaptions with increasing fitness but that is just the visible part of a much wider adaptive process that includes heat adaption, another important area when working for extended periods, especially with the weather as it is at the moment.

I found only 6% solutes in the water interesting, its quite a small amount.

[Dunkanon 380]

Interesting stuff Sandymere, personally I always allow my dogs small drinks whilst working. Although in truth my lurchers arnt worked as hard as some due to other commitments. It would be interesting to hear what the coursing folk think on this subject. There is those out there who know how to put a dog in top condition. I know through the early to mid nineties when we worked gamedogs the practice was to actually gradually dry a dog out prior to competition. There was some who had it down to a fine art and there dogs where able to perform for very long periods of time whilst remaining strong and not overheating.

[sandymere 8,263]

http://www.rossboxing.com/thegym/thegym2.htm

Hi Dunkanon, I believe drying out is common in a number of sports where weight is important, in the link boxers fight in spite of dehydration but "in spite" is the word to note. It is possible when very fit to push a long way, well beyond what an untrained body could, but doing so when dehydrated increases the risks of problems which would conceivable have a negative effect on performance. Doing well in spite of rather than because off may be required in some sports but hopefully not lurchers. What effect weight loss would have on stamina when balenced against the extra pressure that dehydration would have on the cardiovascular system might be an interesting area

[beast 1,884]

heat adaptation - another interesting topic, and definitely dogs (and other animals) can be conditioned to have greater tolerance of overheating.

 

i have an old book here with a section about training pit dogs, and one of the things the author suggests is to gradually, and in a controlled fashion, to reduce the amount of water the dog is given. his theory is that a dog which is trained in such a way will develop a greater effiiciency in internal water use, and therefore when it is woorking hard this gretaer eficiency will limit the effects of dehydration through panting. i think its probably nonsense, but quite interesting that a book written in the victorian era should even be considering such internal processes

[beast 1,884]

oh, and i wonder if the huskies eating snow is actually a cooling rather than hydrating strategy?

[sandymere 8,263]

Could well be an effective cooling strategy, the mouth etc are designed to dissipate heat hence dogs gaping with lolling tongues when hot.

The Victorians certainly were great scientific thinkers, often wrong but much of what we know today had a start in that era.

[bunnys 1,228]

plenty good fatty grub and a squirt a haydration drink, nothing new sensible management the old mars bar little bits every so often , but has said the energy bars do the trick ,and breaks between long sessions .interesting post and might i say one of the most important .atb bunnys.