Swimming Outdoors

It's that time of year when people become interested in swimming their dogs in the local rivers, lakes and sea. I am often asked about it and whilst I don’t want to be a party pooper if you are looking for a therapeutic effect you will not find it there, and the risks of open water swimming should be considered

Currently the local sea temperature in Calshot is 15°C (16-18° elsewhere across Hampshire)

The nearest lake (Ellingham), ranges from 5.2 – 12.9°C with the highest temperature being end August, so on average is 9°C, currently it is recording 10°C

So what does this mean?

Water temperatures provide increased resistance so is physically more difficult to swim through. There are also physiological effects; impacts on the heart, respiratory system, nervous system, blood glucose, blood lactate and of course core body temperature.

Hydrotherapy pools/treadmills are heated to temperatures between 29-32°C, studies have shown this to have the optimal therapeutic effect.

When the effects of water temperatures of 25°C, 33°C and 37°C were compared in a study the following results were documented;

Heart; The heart rate increases in lower temperatures as the normal reflex becomes inactivated due to a decrease in the returning blood volume.

Respiration; Significantly lower respiratory rates were observed (although we tend to see higher rates in warm water as they do have reduced cooling ability).

Neurological; The colder water dampens nociceptor stimuli (nerve endings); great for local pain relief which is why we cold pack injuries but not good for informing the dog of impending tissue damage as it slows pain signals.

Metabolic; Blood glucose significantly increases in colder water (using up those energy stores) and blood lactate is also increased, thought to be due to shivering, but also due to decreased blood supply and oxygen to the muscles.

Core body temperature reduced by 3% in 25°C water during swimming, so what would that drop be at 15-20°C…

Hypothermia is unlikely in the Summer but is a higher risk for small dogs, senior dogs, and puppies. It is also a higher risk when air temperature is also low, windy conditions, or if they stay wet for a long duration afterward.

Hypothermia results in bradycardia (low heart rate), respiratory depression, delayed reflexes, depression, loss of consciousness (cerebral metabolic suppression).

During hydrotherapy we are mostly concerned in therapeutic effects on the soft tissues and joints so what are the effects of low temperatures on those…

Vasoconstriction occurs; there is reduced blood flow to the periphery to protect vital internal structures, this results in reduced pliability/elasticity of the muscles, ligaments and tendons so they are more likely to injure as the tissues contract and become tense, this also results in high joint pressure, reduced range of motion and loss of power/function.

Flaccid Tail may occur which is caused by muscle contraction resulting in constriction of blood flow to the tail.

These effects may make getting out of the water more difficult for your dog, not to mention any underwater obstacles/debris, currents, water inhalation/ingestion.

Lack of a hydrotherapist also means a lack of support, guidance, limb positioning and monitoring (heart rate, respiratory rate, discomfort, movement patterns, adequate rest intervals, fatigue, stress, distress).

The dangers of water inhalation and intoxication

During the summer months there are reports of genuine medical emergencies with pet dogs after swimming at the beach or river, this is usually caused by either water inhalation or ingestion.

With inhalation the water is aspirated into the airway and is especially problematic in brachycephalic breeds, deep chested breeds and individuals suffering from conditions such as laryngeal paralysis. Symptoms can occur 2-3 days following the incident.

Water intoxication occurs when a large quantity of water is swallowed, usually as they repeatedly fetch a toy/ball from the surface of the water or repeatedly dive. Each time they collect the toy they scoop up water along with it, and then water soaked up by the toy travels down the oesophagus and if they also mouth and squeeze the toy even more is ingested.

Fortunately, this is quite rare, it causes a diluted effect to the blood and blood sodium levels fall to a dangerously low level. In response the body tries but fails to excrete the water due to the volume and swelling occurs, this is especially dangerous if the brain is affected.

Those at higher risk are small dogs, high energy water lovers and lean dogs.

Dirty Water

Registered hydrotherapy centres are required to upkeep our water, this means testing temperature, sanitation chemicals (Bromine or Chlorine) to a specific functioning level, optimal pH and solid levels, they are checked and adjusted 2-3 times per day.

Weekly we treat the water with an overdose of ‘shock’ sanitiser to keep free from algae, fungi, bacteria etc

Alongside this we have our water tested by an external laboratory monthly to ensure the water is free from bacterial, viral and fungal infections.

How clean is Hatchett Pond or Beaulieu River??? I know I’ve seen cows defecating and urinating in there…

Have your dogs had vomiting or diarrhoea after swimming in lakes and streams?

I’m not going to progress to body position (float coat or not) or limb movement (can you see the legs moving properly?), the dogs fitness and strength but they are also important considerations.

So I’m also not saying never to let you dogs in water, on a hot day water can be a life saver, and we all want our dogs to have fun but it is not an alternative to hydrotherapy. Have fun and stay safe