1. Where Dogs Sweat and Why It Is Not Enough for Cooling
Unlike humans, who have sweat glands all over their bodies, dogs have very limited sweating abilities. Veterinary resources explain that a dog’s sweat glands are primarily located on their paw pads [2]. Because these glands are concentrated in such a small area, they play only a minor role in cooling the entire body [1].
While dogs do have glands connected to hair follicles all over their bodies, called apocrine glands, these are not used for temperature regulation [3]. These glands may become moist when a dog is nervous or hot, sometimes leaving wet footprints, but this does not help them cool down significantly [3]. Therefore, the main method dogs use to shed excess heat is not sweating, but panting and the evaporation of saliva [1].
2. How Panting Moves Water from a Dog's Body into the Air
Panting is essentially a process of moving water from the body into the air. When water evaporates, it takes heat away from the surface it leaves. This is the same principle that makes your hand feel cool when air blows over it after you wet it. Dogs use the moist surfaces inside their mouths and noses to perform this evaporation instead of using sweat [4].
During panting, a dog quickly inhales air, moistens it, and exhales it. The moisture evaporates from the tongue, the nasal passages, and the wet inner surfaces of the lungs [4]. Veterinary texts note that evaporation occurs mainly from the moist mucous membranes of the upper airway, which includes the path from the nose to the trachea [5]. The evaporation from the surface of the tongue is also considered one of the most important methods for a dog’s temperature regulation [5].
3. How Dogs Change the Speed and Depth of Their Breathing When Panting
Panting is defined as controlled breathing where the rate of breaths increases, but the volume of air moving in and out with each breath decreases [6]. The goal of this rapid, shallow breathing is to increase ventilation in the upper airways, which enhances heat loss through evaporation [6].
By taking many shallow breaths instead of deep ones, the dog keeps a constant flow of air moving over the moist surfaces of its airways. This continuous airflow helps carry away the heat generated by evaporation [6].
4. How Dogs Use the Nose and Mouth Differently as Heat Increases
As the need to lose heat increases, the way a dog breathes changes. A study from 1981 observed three dogs and identified three distinct patterns of panting as evaporative heat loss requirements grew [7]. The patterns changed in this order: inhaling and exhaling through the nose; inhaling through the nose and exhaling through both the nose and mouth; and finally, inhaling and exhaling through both the nose and mouth [7].
In all the patterns reported in this study, the nose was used. Additionally, the abstract of a physiological study mentions a mechanism where heat is exchanged inside the nose, potentially cooling the brain selectively through blood vessels [6]. However, the materials referenced do not clarify how much this selective brain cooling actually works in dogs [6].
5. The Limits of Panting: How Humidity and Effort Make Cooling Harder
While panting is effective, it has significant limitations. Veterinary resources explain that in environments with high humidity, the ability of panting to release heat decreases because evaporation slows down [8]. Another source notes that high surrounding humidity reduces efficiency and increases the risk of heatstroke [5]. This is similar to how wet laundry takes longer to dry on a humid day.
Panting also has a physical cost. Because it involves moving the muscles of respiration, the act of panting itself generates heat [8]. Furthermore, some articles on pet websites suggest that because the surface area of the mouth and tongue is relatively small, panting is not a highly efficient method of cooling [10]. This view is from pet-focused media and should be read as a reference point rather than definitive medical advice.
6. Why Short-Nosed Dogs Face Higher Heatstroke Risk and When to Walk Dogs Safely
Dogs with short noses, known as brachycephalic breeds, are at higher risk for heatstroke. Veterinary materials state that these dogs have partially obstructed upper airways, which makes temperature regulation difficult [5]. A normal dog’s body temperature is typically between 100.5 and 102.5 degrees Fahrenheit (about 38.1 to 39.2 degrees Celsius) [2]. If a dog cannot regulate its temperature and its body temperature rises above 105 degrees Fahrenheit (about 40.6 degrees Celsius), it can lead to heatstroke [2].
Because dogs have fur and are nearer the hot ground, they also absorb heat from the ground easily. The Japanese Ministry of the Environment calls for walking dogs during cool times, such as early morning or night, to avoid this [9].
To understand evaporation better, you can try a simple experiment at home. Wet both hands slightly. Blow slowly on one hand and quickly on the other. Compare which hand feels cooler. This demonstrates how increased airflow aids evaporation.
7. How to Observe Panting in Dogs Safely and Where to Learn More
If you want to learn more, you can observe a dog on a walk from a safe distance. Look at how the tongue is positioned and how the mouth is open. Notice how these change with heat and movement. Do not approach or touch the dog.
For official information, the Japanese Ministry of the Environment provides guidance on preventing pet heatstroke in Japanese. Please note that this article is not veterinary advice. If you have concerns about your dog’s health or temperature, always consult a veterinarian.