[Written by a Veterinarian] Heatstroke in Cats: Causes, Symptoms, and Countermeasures Explained in Detail | When Should You Visit the Vet?

The days of intense heat continue. Perhaps because we cannot live without air conditioning, while heatstroke is a major concern in this heat, we must also be careful about summer fatigue. In this article, we will provide a detailed explanation of summer fatigue in cats.

Do cats get summer fatigue? What are the causes?

Physical traits that make cats prone to summer fatigue (differences in fur and sweat function)

The ancestor of the cat is the Near Eastern wildcat, which lived in the desert. For this reason, they are relatively heat-tolerant animals. Cats' bodies evolved to adapt to life in the desert; they developed dense fur to protect their skin from the sun's rays. And, because drinking water was scarce, they evolved to sweat only from their paw pads to avoid wasting any internal body water. These mechanisms have been passed down to this day without change.

In Japan, the air is not only hot but also humid. In such conditions, heat easily becomes trapped inside a cat's body, leading to heatstroke or summer fatigue.

The impact of living environment: room temperature, humidity, and water intake

A comfortable living environment for a cat is a temperature of 26–28℃ (79–82°F) and 40–60% humidity. When the room temperature exceeds 30℃ (86°F), the risk of heatstroke and summer fatigue rises. Even if you use air conditioning to control temperature and humidity, it is not uncommon for the room temperature to exceed 30℃.

Furthermore, cats are creatures that do not drink much water. Because their ancestors lived in the desert, their bodies evolved to survive on very little moisture. Consequently, they are also animals that are prone to dehydration.

Loss of appetite or lethargy may not always be "summer fatigue"

Summer fatigue presents with symptoms such as loss of appetite, vomiting, diarrhea, and a general lack of energy; however, it does not mean that every such symptom appearing in summer is due to summer fatigue. These symptoms can be caused by various illnesses, including kidney disease, cancer, and diabetes. Therefore, self-diagnosis is extremely dangerous.

Main symptoms of summer fatigue in cats

Not eating, not drinking water, and sleeping all the time

Due to the heat, digestive function gradually declines. As with us humans, a lack of appetite is a common effect of summer fatigue. Cats lose their appetite in the same way. Moreover, due to this decline in digestive function, they also become less inclined to drink water. As they are unable to eat, they cannot secure the calories necessary for activity and will try to conserve energy by sleeping.

Vomiting, diarrhea, and loss of energy are also warning signs

A decline in digestive function doesn't just lower appetite; the inability to digest food properly leads to vomiting and diarrhea. If vomiting and diarrhea persist and the cat stops eating and drinking, its energy levels will gradually fade. Be alert if you notice things like, "The cat seems to be vomiting more frequently lately" or "The stool seems softer than usual."

What "small changes" should owners notice?

While heatstroke causes sudden, life-threatening symptoms such as lethargy, labored breathing, and high body temperature, summer fatigue is characterized by a long period of "feeling slightly off." That sense of "something isn't quite right" is often a sign of summer fatigue. Watch for warning signs like reduced appetite, decreased water intake, spending more time sleeping, increased frequency of vomiting, or softer stool than before. If left unchecked, dehydration and damage to internal organs can become serious.

Preventing summer fatigue in cats: Tips for temperature, water, and food

What is the appropriate air conditioner temperature for cats? Guidelines for temperature and humidity

Just because cats lived in the desert doesn't mean they can withstand the heat. They do not do well with heat combined with humidity. A comfortable environment for a cat is a temperature of 26–28℃ and 40–60% humidity. Some cats dislike direct air conditioning, so you should provide a place where the breeze does not blow directly on them. It is also not uncommon for cats to wander into rooms without air conditioning. In such cases, it is a good idea to circulate the air with a circulator fan or provide a cooling mat.

Tips for encouraging your cat to drink water (running water, multiple water bowls)

Cats cannot drink a large amount of water at once, so it can be difficult for them to stay sufficiently hydrated in the summer. Be more attentive to their drinking water than usual during the summer months.

Because cats do not often seek out water on their own, place multiple water bowls throughout their living space.

If they don't seem to be drinking much from their current container, try changing the bowl. Cats often prefer ceramic or glass bowls. Water fountains, which provide running water, are also popular with many cats. Since water spoils easily in the summer, regular changes of the water and filters are necessary.

Support hydration with wet food and soups

For cats that don't drink much water, use wet food and soups to help them stay hydrated. Replacing their regular food with wet food or adding soup increases the moisture content of their diet. You can also mix a little soup into their drinking water to add flavor. However, because food spoils quickly in the summer, you must change it frequently.

How to deal with summer fatigue in cats and when to see a veterinarian

Emergency care you can do at home (ice packs, oral rehydration)

Even if the symptoms of summer fatigue are mild, they will worsen without proper care. If your cat is in a hot environment, use ice packs to cool their body and lower their temperature. If they are conscious and able to drink water on their own, provide an oral rehydration solution designed for pets and go to a veterinary clinic immediately.

Guidelines for visiting a veterinarian

Even if the symptoms of summer fatigue are mild, you should not simply "wait and see." Dehydration can trigger other health issues. If the situation where they are unable to eat persists for more than a day, be sure to visit a veterinary clinic. Cats are sensitive to fasting.

A visit to the clinic is also necessary if vomiting continues. Vomiting is not just a sign of summer fatigue; it could also indicate other diseases.

Beware of the differences between summer fatigue and heatstroke or internal disease

The symptoms of summer fatigue also appear in various other diseases. The risk of heatstroke is particularly high during this season. While heatstroke causes rapid, severe symptoms, its initial signs can include a hot body, labored breathing, loss of appetite, and vomiting. If you just watch and wait, it will only worsen. The same symptoms also appear with internal diseases like kidney disease or diabetes. Without appropriate treatment, these will also worsen.

Do not self-diagnose as summer fatigue; it is necessary to consult a veterinarian.

Conclusion: Managing life for a cat that won't succumb to the summer heat

How to create a "comfortable summer" for cats

Summers these days are very hot, and it is difficult to get by without air conditioning. The same applies to cats. Although electricity costs will increase, use your air conditioner effectively. If your cat dislikes the direct breeze, use a circulator fan to circulate the air.

Daily adjustments and observation by the owner are key

Even if you provide a comfortable environment with air conditioning, cats can still get summer fatigue. It is necessary to be creative with wet food and drinking water to ensure they stay hydrated. And if they act even slightly strange, a visit to a veterinary clinic is necessary. Be sure to check your cat's food intake, water consumption, activity levels, and toilet habits.

Do not ignore "a slight lack of energy"

Summer fatigue involves a lingering state of feeling somewhat sluggish. However, the same thing can happen with other illnesses. Furthermore, if this state continues for a long time, it can lead to a more serious situation. Do not overlook even small changes, and be sure to consult a veterinarian.