We all get out of breath occasionally. Whether it’s from running a marathon or just running up the stairs too quickly! Breathing fast is usually normal, though it can be a sign of a lack of fitness or even disease. If your new puppy is breathing fast, you might be wondering if it’s normal or if you need to visit a vet. Today we will go over the various reasons why your puppy might be breathing fast.

Normal breathing in dogs

We hope that you all remember from biology class that breathing in brings oxygen into our lungs, swapping it with carbon dioxide to be expelled. The oxygen goes round the body to our cells, providing them with energy to function, producing more CO2 as a waste product. Without this critical action, we pretty much cease to function… we die!

Our bodies are pretty good at knowing what they want. Special receptors in arteries and on the brainstem called chemoreceptors detect the levels of CO2 and O2 , and the blood’s pH (acidity) constantly. When our bodies are metabolising (producing energy) fast, such as during exercise, we use up oxygen and produce more carbon dioxide. Increased carbon dioxide leads to a drop in the pH of the blood – it becomes more acidic. So if the chemoreceptors detect low blood pH and O2, and high CO2, they tell the lungs and associated muscles to work faster (tachypnoea or breathing fast). This brings oxygen into and CO2 out of our bodies more quickly, restoring balance. Once the levels are normal, the receptors tell the lungs to slow down again.

So why is your puppy breathing fast? Probably because its chemoreceptors have detected low O2 and blood pH, and high CO2, and are compensating. Question answered!

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Causes of fast breathing in puppies – Tachypnoea

Okay, okay. You probably want a bit more information than that. Let’s break down the specific causes of fast breathing in puppies into groups, and go from there. For reference, a puppy’s normal resting breathing rate is 15-40 breaths per minute, a little higher than an adult dog’s 10-30.

Normal causes of tachypnoea in puppies

There are plenty of normal reasons why your puppy might be breathing fast. As mentioned above, the most likely reason is exercise. If a puppy has been running around all afternoon, its body will have a huge demand for oxygen to supply the hard-working cells, and a lot of CO2 to remove. Breathing fast will help correct this quickly. 

Stress, excitement or fear are all linked to the stress hormone cortisol. Also known as the fight-or-flight hormone, when it activates it increases the heart rate. As the heart is a muscle, it needs oxygen to function. A faster heart leads to tachypnoea as the lungs compensate to bring more O2 to the heart. Has your puppy just had a fright or gotten excited? This might be the cause of the fast breathing rate. Cortisol is also responsible for an increased breathing rate due to pain. If your puppy sadly hurts themself, they may breathe faster.

Finally, the lungs have a secondary function of helping to cool the body down by expelling warm air and inhaling cooler air. As dogs only sweat through their feet and noses, the lungs are particularly important in regulating heat. Heat is produced secondarily to exercise or just because of the environment – if your puppy is too hot, it will pant fast to lose some of that heat. Be especially wary of exercising puppies on hot days, as the two heat sources can overwhelm their compensation mechanisms and lead to heatstroke – heatstroke can be fatal, especially in puppies, so always help them cool down if they are panting too hard. A fever due to illness can cause rapid breathing for the same reason.

The heart is closely linked to the lungs. It pumps blood to the lungs, allowing oxygen and carbon dioxide to be exchanged. If the heart isn’t doing its job properly, the lungs sometimes have to compensate by breathing faster. Most heart diseases in puppies are present from birth – developing heart disease at such a young age is rare. 

The developing heart undergoes a lot of changes before a puppy is born. However, sometimes these changes go wrong or don’t take place, resulting in congenital heart malformations, such as narrow vessels, holes in the heart or leaky valves. These cause the blood to flow in the wrong direction, or the heart to have to work harder against pressure. The result is excessive strain on the heart. We can sometimes hear these defects with a stethoscope as a heart murmur. Only the most serious heart defects cause disease and tachypnoea as a puppy – many will either cause no effects or result in disease later in life.  Puppies with heart disease may have soft coughs and be very lethargic.

Lung diseases and fast breathing in puppies

Lung diseases affect the lungs’ capacity or performance, resulting in reduced oxygen intake. To compensate, the lungs speed up – lung disease often results in very fast but shallow breathing. There are many kinds of lung disease. 

In puppies, the most common are probably infectious lung diseases. These include kennel cough, bronchopneumonia, viral infections like influenza, and lungworm. These diseases damage the lungs, fill them with infection and reduce the area available for oxygen and carbon dioxide to be exchanged. Secondary infections after inhaling objects such as grass seeds (or just a simple blockage) are also a common cause of tachypnoea. Generally, puppies with lung infections also have a fever, a cough and are quite poorly, so please speak to your vet if you suspect a lung infection.

Sometimes newborn puppies can be born breathing very rapidly as a result of their lungs not functioning properly. When animals are born, the lungs are often immature and full of fluid – they usually clear within a few hours of life but they can sometimes take longer, especially if the puppy was born premature. In these cases, the puppy will often be breathing quite fast. Newborn puppies are very vulnerable, so a puppy like this will need a lot of veterinary care.

Finally, the lungs can also be physically damaged, reducing their capacity and resulting in compensatory tachypnoea. Examples include bruising or puncture after an accident, or damage to the ribs or diaphragm that control lung movement. These events are obviously an emergency as there could be other issues going on like internal bleeding.

Not all tachypnoea is directly linked to the heart or lungs

If there isn’t enough oxygen in the blood, the lungs compensate, breathing faster – sometimes there isn’t enough oxygen in the blood because of an issue with the blood itself. Very sick puppies can become hypovolaemic – this means there isn’t enough blood fluid to transport the oxygen the puppy needs, so the lungs compensate. These puppies are often dehydrated, e.g. due to severe vomiting and diarrhoea. Hypovolaemia can also occur due to bleeding. If a puppy loses too much blood, there won’t be enough to supply all the tissues with oxygen, so breathing increases. 

Finally, the red blood cells themselves (the cells that carry oxygen) can be low (anaemia) or damaged. There are many causes of red blood cell dysfunction, including chronic disease, parasites, autoimmune diseases, carbon monoxide or onion poisoning. Puppies with these issues are often pale, cold and have blue gums. All of the above are emergencies that need to be seen by a vet ASAP.

The abdomen is close to the lungs and the abdominal organs even push up on the diaphragm when animals breathe out to help expel air. But if the organs get too big they can start to compress the lungs too much, they reduce its capacity for oxygen movement and causing tachypnoea. One of the most common reasons for a swollen belly in puppies is worms – puppies should be treated for worms regularly to prevent this. Swollen tummies can also occur due to blockages from swallowed objects or stools, twisted intestines or fluid in the abdomen. There is also a rare congenital disease that allows abdominal organs to enter the thorax where the lungs are, pushing on them – we can correct this with surgery. A puppy with a big swollen belly should always be investigated for these diseases. 

Brain damage and fast breathing in a puppy

Brain damage can sometimes result in tachypnoea, as well as other serious neurological issues. There is usually an underlying cause, and in puppies is probably due to an accident. If your puppy has bumped their head, please speak to a vet quickly, especially if they are breathing fast, are collapsed or bleeding, or are an abnormal colour.

Final Thoughts

We hope that our big long list of causes of rapid breathing in puppies hasn’t frightened you too much. For the majority of puppies, breathing fast is a short-lived and normal effect and shouldn’t worry you. You should only consider talking to a vet if the puppy is breathing fast for prolonged periods of time, or there are other signs of disease. More than likely, you just have a very excitable puppy who won’t calm down!

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