K9 Trail Time Interview with an expert (or two) Dr Anne Carter & Emily Hall MRCVS Experts on Heatstroke in Dogs

There is so much information out there about how we should or shouldn’t look after our dogs in the hotter weather. Is it safe to run our dogs? Should we run our dogs? How should we exercise them? There are so many different questions and if you ask on any canicross page you will get a range of answers. As we at K9 Trail Time are trying to get the best information out there we went straight to Dr Anne Carter and Emily Hall MRCVS from Nottingham Trent University who have, over the past few years been looking at how dogs respond to heat, especially when running in harness. There is very little published research about dogs exercising in hotter or more humid conditions and so the work that Anne and Emily have been doing is invaluable to our dogs.

Dr Anne Carter herself knows about the risks associated with dogs in the heat as she regularly competes in canicross races with her own dogs

The first question everyone wants to know is how do we know if it is too hot? Does the temperature x humidity = 1000 actually mean anything?

As part of our research we calculated the “temperature x humidity” for 210 dogs at 10 canicross races, to see if the “do not run your dog if temperature (oC) x humidity (%) is greater than 1000” guideline was an accurate predictor of “safe” dog temperature. We found no correlation between the temperature x humidity value and dog temperature, or the number of dogs developing hyperthermia, or the number of dogs developing a temperature at risk of heatstroke, so would not recommend using this as a hard and fast rule.

If there is no set way to determine if it is too hot, how do we plan training our dogs over the summer so that they are fit enough for the racing season in September?

Unfortunately, there is no ‘one size fits all’ approach. Black and male dogs are at higher risk, as well as those that are overweight, unfit, dehydrated or have a breathing disorder (including brachycephalic dogs). The important thing is to know your dog, some dogs cope better with the heat than others. Heatstroke is still possible in winter. Dogs can acclimatize but this can take around 6 weeks, something the British weather doesn’t often lend itself to. So if the temperature suddenly increases, the risk may be higher than after a steady increase. Try to exercise in the cooler parts of the day and use alternative keep fit options like swimming. Above all, get to know your dog! Crucially, does your dog stop or slow down when they get too hot (if so you’re lucky), or, will they run until they collapse. If your dog is the latter, you need to be extra careful.

Research has shown that black dogs suffer more in the heat that other coloured coated dogs

What is humidity and why does everyone make a big deal about it? How does it affect the dogs?

As with people, high humidity can make a temperature feel a lot warmer and a run feel a lot harder. It is used to calculate the ‘feels like’ temperature. In high humidity, it is harder for dogs to dissipate heat, making them more at risk of heatstroke. Both humans and dogs rely on some heat being lost through evaporation, in humans we have sweat to evaporate, dogs use panting. At any temperature, a high humidity will limit evaporation, limiting heat loss.

When running our dogs in harness over the warmer months are there things we can look out for to make sure that our dogs aren’t over heating?

Early signs your dog is getting hot include increased salivating, excessive panting that doesn’t stop after rest, and a large and darker tongue. This can progress on to staggering and loss of balance, eventually causing collapse. One early sign could be that your dog stops pulling, or starts to stumble and trip more frequently. Reducing speed can help and letting them take a dip to cool down throughout the run.

Allowing your dog plenty of breaks to cool off if running in higher temperatures or if you suspect they may be getting warm

 

What if my dog doesn’t really pull in harness, they just trot, and does that make a difference?

The less effort the dog puts in to a run, the lower the temperature of the dog-on average. There is still a risk of heatstroke, particularly in very hot weather, but we did find slower speeds didn’t increase body temperature as much as fast speeds.

 

Can I run my dog in their cooling coat? It helps them keep cool at home…

The problem with cooling coats is they can affect the dog’s natural cooling mechanism. The only study to look at cooling coats put them on greyhounds after a sprint race. Those in cooling coats had a higher body temperature than those without. There is no current evidence investigating the use of cooling coats during exercise, so we can’t comment on this, but if it’s hot enough that you think you might need a cooling coat, then perhaps a walk in the shade or a dip in the river might be a better option.

If that isn’t a good idea then how do I cool my dog down after a run? What if my dog doesn’t like getting in water?

After a run, active cooling is a good idea. Standing in or lying down in water, splashing luke warm water under their belly. Avoid using cold or iced water or submerging them in it as this can restrict blood vessels in the body and increase the risk of shock. If they don’t like water, they can be walked round or rested in the shade to cool them off, air movement is also very effective so pick a windy spot, or use the car air conditioning or a fan if you’re worried.

Sometimes our dogs put on weight over the summer as they do less, does this affect how they cope in warmer temperatures?

Increased weight can increase a dog’s ability to cope with the heat. It your dog is a little less svelte than usual, you will need to be more cautious when exercising in warmer weather. Reducing food intake relative to exercise can help keep the pounds off through the summer

Many factors affect a dogs’ ability to cool itself but keeping them fit and a healthy weight will help

Our dogs do agility and other sports over the summer and always seem fine; should we be watching for anything whilst competing in other sports or is it just harness sports?

Heatstroke is a risk for all dogs at any time but particularly when exercising in warm weather. Although sports such as agility are for much shorter periods of time, ambient temperatures are often higher so the risk of heatstroke is just as real.

If you are worried that your dog is suffering from heatstroke, active cooling is key. The car air con can be very useful, but the best chance of survival is to get them to the vets as quickly as possible.

 

So it sounds like there are still quite a few unanswered questions regarding heatstroke in exercising dogs, do you have any plans for more research?

We have just finished surveying owners of sports dogs about methods of cooling used, so expect to hear the results of that study in the hopefully not too distant future! We are also currently researching cooling after canicross races, measuring the dog’s temperature for up to 20 minutes after a race to see what impacts how quickly they cool, this study is still on going so you’ll have to wait a little longer for the results of that one.

Emily Hall MRCVS who has devoted a huge amount of time to this research to help dog owners recognise the signs of heatstroke and prevent unnecessary cases of it

Our next big research project is looking at activity levels in all types of dogs, any age, any breed and any health status, looking at how much exercise dogs are getting in general, but also how extreme weather impacts their ability to exercise.

The results of all our studies can be found on our blog: https://hotdogscanineheatstroke.wordpress.com/

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Heatstroke in dogs (a temperature monitoring study in sport dogs)

Dog welfare is of upmost importance to us here at K9 Trail Time and so we spoke to Dr Anne Carter and Emily Hall MRCVS who have been conducting a temperature monitoring study for Nottingham Trent University, with dogs who have been at some of the races we attend, hosted by the Canicross Midlands club.

The aim of the study is to try and discover what factors affect dogs core temperatures and potentially put them at risk of heatstroke or hyperthermia. The study is still in it’s early stages and results have yet to be published, as both Anne and Emily feel there is much more research to be done in this area and that they have only begun to scratch the surface of what needs to be looked into to give dog owners and in particular, owners of dogs who compete in sports,  a useful guide to help them prevent their dog from suffering hyperthermia.

Dr Anne Carter put together these notes for us so that we could share them with our followers but there will be more to follow due to the full study not having been completed yet. We have added additional notes not within the speech marks, which summarise the points as we see them.

Prior to the study it was noted…

“Dark coated, male dogs appear to be at higher risk of hyperthermia. This corresponds with findings from literature that suggest higher risk groups include: brachycephalic breeds, those with respiratory disorders, overweight dogs, and poorly conditioned dogs.”

So this suggests that dogs who are unfit and unused to exercising in higher temperatures will be more at risk than those who have been sensibly and gradually acclimatised to working in warmer temperatures. We have always advocated light training through the summer months for this reason but distances need to be kept shorter and measures taken to ensure your dog never over works in the heat.

Training runs in warmer months should be kept short to avoid over heating

Training runs in warmer months should be kept short to avoid over heating

The study so far has taken the previous notes into account but developed them…

“Normal core temperature in the literature appears to be 38.3-39.2⁰C – We found a normal core temperature range of 37.4 – 39.1⁰C.”

“‘Knowing your dog’ is key. Some dogs appeared to be naturally hotter at both resting and post exercise temperature. Therefore, their normal range may be different to another dog. This doesn’t appear to be breed specific.”

Which is indicative of the individuality of the dogs measured in the study so far and would imply that it is very useful to understand your own dogs’ regular resting core temperature, so you can be aware of anything abnormal specific to your dog.

“Hyperthermia in canine patients is defined as a core body temperature above 39.2oC. Canine heat stroke is therefore associated with a core body temperature above 40oC

Both these temperatures were exceeded in (some) dogs after a 5km run, but dogs quickly returned to normal range.”

This would indicate that dogs very quickly reach internal body temperatures which would be considered abnormal and dangerous to dogs, however the fact the dogs return to normal very quickly and that there has been very little study done on this so far, seems to suggest that this is probably perfectly normal and as long as we are aware of our dogs’ limits, is not harming the dog in any way. This type of raise in body temperature is probably occurring in any daily activity we do with our dogs but we would not necessarily be aware of it because we wouldn’t be monitoring their core temperature so closely unless we were concerned.

Allowing your dog to cool off when they require it by planning run routes with water is a great way to know your dog will be happy

Allowing your dog to cool off when they require it by planning routes with water is a great way to know your dog will be happy

“If heatstroke occurs, active cooling should be undertaken using lukewarm (not cold water), air con in the car, mist spray of fans. Cooling coats so far, have not been shown to be effective. Veterinary care should be sought immediately to improve survival chances (delays over 90 minutes increased fatality rates significantly in the literature).”

We discussed in great detail the things associated with heat stroke and the main signs of over heating are as follows: restlessness, seeking out cool areas/shade, looking to lie down, excessive panting, excess salivation and thick sticky saliva. Also look for glazed eyes, red or very pale pink (rather than healthy pink) gums, stiffness in movement which can lead to staggering and any anxiety or agitation. If your dogs displays any of these signs then it must be taken straight to a vet as any delay may cost your dog it’s life.

The main issue with heatstroke in dogs is shock, so even if you get your dog to a vet (ideally within 90 minutes of the dogs first showing signs of heatstroke) there are no guarantees that they will be able to undo the damage done to the internal organs by shock.

The things you can do to help your dog if it has been affected by the heat is to cool the underside of their body with cool but not cold water (shock damage can be increased by using ice water), ensure air flow over the dogs’ body i.e. with a fan or breeze in a car and don’t put anything over them which can trap the air in the dogs’ coat, so no wet towels, blankets or coats.

Remember that dogs lose heat through their paws, so boots can restrict a dogs’ ability to cool efficiently, therefore only use boots in cooler weather and never to protect your dogs feet from hot pavements, if it’s too hot for paws on pavements, it’s too hot full stop.

Boots s - Photo courtesy of Fay Frost Photography

Boots should only be used when it’s cold enough for them not to interfere with a dogs ability to cool itself – Photo courtesy of Fay Frost Photography

Dr Anne Carter and Emily Hall MRCVS will be continuing their studies throughout this dog sport season so if you would like to take part they will be at some (not all) of the Canicross Midlands race series and also some training runs, asking for volunteers. They have also provided this link on body temperature in racing greyhounds for anyone who is interested in a published study. It’s open access so free to all. http://journal.frontiersin.org/article/10.3389/fvets.2016.00053/full

We will be following the progress of this study and hope it will help to raise awareness of heatstroke for all dog owners not just those taking part in the dog sports.

Happy trails and if in doubt – don’t run!