Do dogs’ hearts beat differently than humans? While both species share fundamental cardiac structures, there are notable distinctions in how their hearts operate and respond to their environments. Exploring these differences offers a deeper understanding of canine health and physiology.
Heart Rate Variances
A primary difference between canine and human hearts lies in their typical resting heart rates. For most adult humans, a normal resting heart rate usually falls within a range of 60 to 100 beats per minute (bpm). In contrast, a dog’s normal resting heart rate varies significantly based on its size and breed. Smaller dog breeds typically have faster heart rates, ranging from 90 to 140 bpm, while medium breeds average 70 to 110 bpm, and large breeds generally fall between 60 to 90 bpm. Puppies can have even higher rates, sometimes reaching 180 to 220 bpm.
Beyond just the speed of the beat, a unique characteristic of a healthy canine heart is the presence of sinus arrhythmia. This respiratory-linked fluctuation causes a dog’s heart rate to naturally increase during inhalation and decrease during exhalation. It is common in dogs and is rarely a cause for concern, distinguishing their heart rhythm from the typically more regular rhythm observed in humans.
Understanding the Canine Heartbeat
Delving deeper into the mechanisms, the canine heart, like the human heart, is a four-chambered organ, yet subtle anatomical and physiological distinctions contribute to their differing heartbeats. Dogs often possess more pulmonary veins than humans, sometimes up to twice as many, which carry oxygenated blood from the lungs back to the heart. This anatomical variation influences blood flow dynamics within the heart.
A significant factor influencing the canine heartbeat, particularly the phenomenon of sinus arrhythmia, is the vagal nerve. This nerve plays a substantial role in regulating a dog’s heart rate, causing it to fluctuate with respiration. This greater beat-to-beat variability in dogs allows for a wider spread between their minimum and maximum heart rates, setting them apart from human cardiac patterns.
Factors Affecting a Dog’s Heart Rate
A dog’s heart rate is influenced by a variety of internal and external elements. Body size and breed play a significant role, with smaller dogs generally exhibiting faster heart rates compared to their larger counterparts. Age also impacts heart rate, as puppies typically have higher rates than adult and senior dogs. Activity level directly correlates with heart rate, which naturally increases during exercise or play. Emotional states, such as excitement, fear, stress, or anxiety, can also cause a dog’s heart rate to elevate considerably. Underlying health conditions, including fever, pain, dehydration, blood loss, or certain heart diseases, can also affect heart rate, sometimes leading to abnormally fast or slow rhythms.
How to Check Your Dog’s Heart
Owners can gain insight into their dog’s heart health by learning to check their pulse. The most accessible location to feel a dog’s pulse is the femoral artery, located on the inner thigh where the leg meets the body. Alternatively, for smaller dogs or if the femoral pulse is difficult to locate, the heartbeat can sometimes be felt directly on the left side of the chest, just behind the elbow.
To measure the heart rate, use your index and middle fingers to gently press on the chosen pulse point, avoiding your thumb as it has its own pulse. Count the number of beats felt in 15 seconds and then multiply that number by four to calculate the beats per minute. A normal pulse should feel strong and consistent, although the natural sinus arrhythmia will cause a slight irregularity in rhythm. If the pulse feels very weak, is excessively fast without exertion, or exhibits an irregularity beyond the normal sinus arrhythmia, these observations warrant a consultation with a veterinarian.