High blood pressure (also called hypertension) isn’t just a human health issue—it can quietly affect cats too. The tricky part is that cats are masters at acting normal even when something serious is going on. That’s why feline hypertension is often discovered only after it’s already started causing problems, especially with the eyes, kidneys, heart, or brain.

If you’ve ever wondered why your veterinarian is so keen on routine checkups for older cats, blood pressure is a big reason. Measuring it can reveal hidden disease early, and early treatment can protect vision and organ function. This article walks through the most common symptoms, what causes high blood pressure in cats, and how testing works (including what to expect at the clinic).

Because the target keyword for this topic is veterinary cardiologist, we’ll also talk about when heart-focused expertise matters and how hypertension ties into cardiac health—without assuming every cat with high blood pressure has heart disease.

Why feline blood pressure matters more than most people realize

Blood pressure is the force of blood pushing against the walls of arteries. When that pressure is persistently high, it can damage delicate tissues over time. In cats, the organs most vulnerable to this damage are sometimes called “target organs”: the eyes (retina), kidneys, heart, and brain.

The frustrating part is that many cats won’t show obvious signs until the condition is advanced. That means hypertension can be present for weeks or months before anyone notices. Regular screening—especially for senior cats or cats with chronic conditions—can catch it before permanent damage happens.

Another reason it matters: hypertension in cats is often secondary, meaning it’s caused by another underlying problem. So finding high blood pressure can be like finding a clue that leads to a bigger diagnosis—one that may be treatable or manageable if caught early.

What “high” means in cats (and why numbers can be confusing)

Blood pressure readings are usually reported as systolic/diastolic, but in cats, veterinarians often focus heavily on the systolic number (the top number). That’s because systolic pressure is most closely linked with risk of organ damage, particularly to the eyes.

There isn’t one single “magic number” that applies to every cat in every situation. Stress can elevate readings (more on that soon), and different clinics may use slightly different equipment. Still, sustained systolic readings in the higher ranges are taken seriously because they correlate with a higher likelihood of complications like retinal detachment or worsening kidney disease.

It’s also worth noting that a single high reading doesn’t always equal a diagnosis. Many veterinarians prefer to confirm elevated blood pressure with repeat measurements, ideally in a calm setting, and interpret the result alongside the cat’s overall health and lab findings.

Signs at home that can point to high blood pressure

Some cats with hypertension seem totally fine at home—until they aren’t. Others develop subtle changes that are easy to dismiss as “just getting older.” Paying attention to small shifts in behavior, mobility, appetite, or vision can help you get ahead of the problem.

Because high blood pressure can affect multiple organs, the symptoms can look very different from cat to cat. One cat might show eye-related signs, while another shows neurological changes, and another just seems a bit off.

Eye and vision changes (often the first obvious clue)

High blood pressure can damage the tiny blood vessels in the retina. In severe cases, this can lead to bleeding, swelling, or retinal detachment. The scary part is how sudden it can feel: a cat may appear normal one day and then bump into furniture the next.

Things you might notice include dilated pupils that don’t respond normally to light, sudden clumsiness, reluctance to jump, or a cat that seems startled when approached. Some cats become anxious or withdrawn because their environment suddenly feels unpredictable.

If you ever suspect sudden vision loss, treat it as urgent. Even if vision can’t be fully restored, rapid treatment can sometimes prevent further damage and protect the other eye.

Behavior and neurological changes

When hypertension affects the brain, signs can include disorientation, pacing, vocalizing more than usual (especially at night), or seeming “not quite themselves.” In more serious situations, cats may have episodes that look like seizures or sudden collapse.

These symptoms are understandably alarming, but they’re also non-specific—meaning other conditions can cause similar signs. That’s why blood pressure checks are often part of the workup when a cat presents with sudden neurological changes.

Even mild brain-related effects can show up as subtle personality shifts: a normally social cat hides more, or a mellow cat becomes irritable. If changes persist for more than a day or two, it’s worth a veterinary visit.

Kidney-related signs that overlap with many other issues

Kidney disease and hypertension are closely linked in cats. Sometimes kidney disease contributes to hypertension; other times, hypertension worsens kidney damage. This can create a cycle where each problem amplifies the other.

At home, kidney-related signs can include drinking more water, urinating more, weight loss, reduced appetite, nausea, or lower energy. None of these symptoms are exclusive to kidney disease or hypertension, which is why testing is so important.

If your cat is older and you’re noticing increased thirst or changes in litter box habits, a blood pressure check is a smart add-on to standard bloodwork and urinalysis.

Heart and breathing changes

Not every cat with high blood pressure has primary heart disease, but the cardiovascular system still takes a hit when pressure stays elevated. Over time, the heart may have to work harder, and some cats can develop changes in the heart muscle.

Signs that warrant prompt veterinary attention include rapid breathing at rest, open-mouth breathing, weakness, fainting, or sudden exercise intolerance (for cats, that might look like refusing stairs or avoiding play). These signs can indicate heart strain or other serious issues.

If your veterinarian suspects cardiac involvement, they may recommend advanced evaluation and, in some situations, referral to a specialist such as a veterinary cardiologist to help interpret echocardiogram findings and tailor treatment safely.

Common causes of high blood pressure in cats

In cats, hypertension is frequently secondary to another condition. Finding the underlying cause is important because it can change both the treatment plan and the long-term outlook.

Sometimes, despite thorough testing, no clear cause is found. This is called idiopathic hypertension. Even then, treatment is still valuable because controlling blood pressure helps protect organs from ongoing damage.

Chronic kidney disease (CKD)

CKD is one of the most common health problems in older cats, and it’s strongly associated with hypertension. Damaged kidneys can contribute to hormone and fluid balance changes that raise blood pressure. At the same time, high blood pressure can reduce blood flow within the kidneys and accelerate kidney deterioration.

This is why many veterinarians recommend routine blood pressure monitoring for cats with CKD—often at diagnosis and then periodically afterward. If hypertension is present, controlling it can be one of the most protective steps you can take for kidney health.

Managing CKD typically involves diet adjustments, hydration support, and sometimes medications or supplements. Adding blood pressure treatment when needed can help stabilize the overall picture.

Hyperthyroidism

Hyperthyroidism is another common condition in senior cats. When the thyroid gland produces too much hormone, it can rev up metabolism and increase heart rate, which can contribute to elevated blood pressure.

Classic signs include weight loss despite a good appetite, increased vocalization, restlessness, vomiting, diarrhea, and sometimes increased thirst. Some cats become unusually affectionate; others become cranky or anxious.

Treating hyperthyroidism (through medication, diet, or radioactive iodine therapy) may improve blood pressure, but some cats still need direct blood pressure medication as well. Monitoring is key because the relationship between thyroid levels, kidney values, and blood pressure can be a bit of a balancing act.

Diabetes and other endocrine or metabolic disorders

Diabetes mellitus is less commonly linked to hypertension in cats than in people, but it can still play a role, especially if there are concurrent kidney changes or other systemic stressors. Other hormonal disorders can also influence blood pressure regulation.

Because endocrine diseases can overlap, veterinarians often look at the full clinical picture: weight trends, appetite, thirst, urination, and lab results. Sometimes the “cause” isn’t one single diagnosis but a combination of age-related changes.

If your cat has an endocrine condition, it’s worth asking whether routine blood pressure checks should be part of ongoing monitoring.

Heart disease and cardiovascular changes

In cats, primary heart disease isn’t the most common cause of systemic hypertension, but cardiovascular health still matters. Some cats have structural heart changes (like hypertrophic cardiomyopathy) that can complicate treatment decisions, particularly when choosing medications and monitoring for side effects.

Hypertension can also contribute to thickening of the heart muscle over time, because the heart is working against higher pressure. This can blur the line between “cause” and “effect,” and it’s one reason follow-up imaging may be recommended in some cases.

If there are murmurs, gallop sounds, arrhythmias, or breathing symptoms, your veterinarian may recommend additional diagnostics to better understand the heart’s role in the overall condition.

Idiopathic hypertension (no obvious underlying cause)

Sometimes, after bloodwork, urinalysis, thyroid testing, and other evaluations, the cat still has high blood pressure without an identifiable trigger. This is more likely in older cats, and it doesn’t mean the hypertension is any less real or any less important.

In these cases, the focus shifts to consistent monitoring and effective blood pressure control. The good news is that many cats respond very well to medication, and owners often report improved comfort and energy once blood pressure is managed.

Even when the cause is unclear, your veterinarian will still keep an eye out for evolving conditions over time—because an underlying issue may become more apparent later.

How veterinarians test blood pressure in cats (and how to make it more accurate)

Measuring blood pressure in cats is non-invasive, but it’s not always straightforward. Cats can experience “white coat hypertension,” where stress in the clinic temporarily raises readings. That doesn’t mean the measurement is useless—it just means technique and context matter.

Most clinics use Doppler or oscillometric devices with a cuff placed on the leg or tail. Your cat may be gently restrained, but many teams aim for a calm, minimal-restraint approach to reduce anxiety and get a more reliable result.

What happens during a typical blood pressure appointment

Usually, your cat will be allowed a few minutes to settle in a quiet room. The veterinary team will choose an appropriately sized cuff (cuff size matters a lot) and take multiple readings. Rather than relying on the first number, they’ll often discard early readings and average the later ones.

If your cat is very nervous, the team may adjust the approach: dimming lights, letting your cat stay in the carrier top, using a towel wrap, or having you present to provide comfort. Some cats do better on the tail than the leg, and vice versa.

If the readings are borderline or unexpectedly high, your veterinarian may recommend rechecking on a different day. Consistency across visits helps distinguish true hypertension from stress-related spikes.

Ways you can help reduce stress-related spikes

Simple changes can make a big difference. Bring your cat in a familiar carrier, use a pheromone spray if recommended, and avoid rushing. If your cat is food-motivated, ask whether treats during the visit are okay.

Schedule appointments at quieter times when possible. Some cats are calmer in the morning; others do better mid-day when the clinic is less busy. If car rides are stressful, consider covering the carrier with a light towel to reduce visual stimulation.

For cats with severe fear, your veterinarian might suggest pre-visit medication to take the edge off. This can improve the accuracy of the reading and make the experience kinder for everyone involved.

Why repeat measurements matter

Blood pressure isn’t static—it changes with stress, pain, and activity. That’s true in people and it’s true in cats. A single measurement is like a snapshot; repeat checks are more like a short video clip that shows the trend.

Your veterinarian may recommend a series of readings over a few weeks, especially before starting medication. Once treatment begins, rechecks help confirm the dose is effective and not pushing pressure too low.

Long-term, many cats benefit from periodic monitoring even when stable, because underlying diseases (like CKD or thyroid issues) can change over time.

Testing beyond blood pressure: finding the “why” and checking for organ impact

When high blood pressure is detected, the next step is usually to look for underlying causes and assess whether target organs have been affected. This is where a thoughtful diagnostic plan can save time (and sometimes eyesight).

Your veterinarian may tailor testing based on your cat’s age, history, and symptoms. A cat with sudden blindness needs a different urgency and focus than a cat with mild, incidental hypertension found at a wellness visit.

Bloodwork and urine testing

Basic bloodwork can evaluate kidney values, electrolyte balance, and overall organ function. Urinalysis adds important context—especially for kidney health—by looking at urine concentration and checking for protein or signs of infection.

Protein in the urine (proteinuria) can be a sign of kidney damage and may influence treatment choices. Hypertension can contribute to protein loss, and reducing blood pressure can sometimes reduce proteinuria as well.

These tests are also useful baselines. If your cat starts blood pressure medication, having pre-treatment values helps your veterinarian monitor safety and response over time.

Thyroid testing

For older cats, thyroid testing is often part of a hypertension workup. A total T4 test is commonly used as a starting point, and additional thyroid tests may be recommended if results are borderline or if symptoms strongly suggest hyperthyroidism.

Because thyroid levels can interact with kidney values, your veterinarian may interpret results carefully and sometimes repeat tests. It’s not unusual for early hyperthyroidism to be subtle on lab work.

If hyperthyroidism is diagnosed, treating it can improve multiple symptoms at once—weight loss, restlessness, and sometimes high blood pressure.

Eye examination and retinal evaluation

If hypertension is suspected or confirmed, an eye exam is often recommended—even if you haven’t noticed vision changes. Retinal damage can sometimes be present before obvious blindness occurs.

Your veterinarian may look for retinal hemorrhages, swelling, or detachment. In some cases, they may recommend a veterinary ophthalmologist, particularly if the findings are complex or if advanced imaging is needed.

Eye findings can also help gauge how urgent treatment is. Significant retinal changes can indicate that blood pressure has been high enough, long enough, to cause real harm.

Cardiac evaluation: when the heart needs a closer look

Depending on your cat’s exam findings, your veterinarian may recommend chest X-rays, an ECG, or an echocardiogram. This is especially common if there’s a murmur, abnormal heart sounds, or breathing changes.

Hypertension can contribute to heart muscle thickening, and some heart conditions can complicate medication choices. For example, if a cat has underlying heart disease, your veterinarian may be more cautious about fluid therapy, certain drugs, or how quickly to adjust doses.

In more complex cases, a referral to a specialist team—often involving internal medicine and cardiology—can be helpful to coordinate the safest, most effective plan.

Where internal medicine fits in for complicated or multi-condition cats

Many cats with hypertension are older and may have more than one health issue at the same time—like early kidney disease plus hyperthyroidism, or diabetes plus chronic inflammation. When diagnoses overlap, it can be hard to know which problem is driving the blood pressure and what to treat first.

This is where internal medicine expertise can be especially valuable. These veterinarians focus on complex medical cases, interpreting layered lab results, and building step-by-step treatment plans that consider the whole cat, not just a single number.

If your primary veterinarian recommends referral, it doesn’t mean anything has gone wrong—it often means they want extra support to get answers faster and tailor treatment more precisely. For pet owners in Nova Scotia, working with a Halifax internal medicine vet can be a practical next step when hypertension is persistent, severe, or tied to multiple body systems.

How lab testing supports diagnosis and safer treatment

Blood pressure is only one piece of the puzzle. Lab testing helps identify underlying disease, track medication effects, and monitor for complications. It can also help determine whether symptoms you’re seeing at home are related to hypertension or something else entirely.

For example, if a cat starts a new blood pressure medication and then seems lethargic or off their food, your veterinarian may want to recheck kidney values and electrolytes. That doesn’t necessarily mean the medication is “bad”—it means dosing and the cat’s overall health need to be balanced carefully.

What a well-equipped lab can do for hypertensive cats

Timely results matter. When a cat has suspected kidney disease, thyroid issues, anemia, infection, or electrolyte imbalances, getting accurate lab data quickly can speed up decisions and reduce delays in treatment.

Lab testing may include chemistry panels, complete blood counts, urinalysis, urine protein measurements, and sometimes specialized endocrine or infectious disease testing depending on the case. In some situations, repeat tests are needed to confirm trends rather than react to a one-time abnormal value.

If your veterinarian refers samples out or collaborates with a dedicated veterinary laboratory, it can improve turnaround times and ensure consistent methods—both of which support better long-term monitoring.

Monitoring over time: trends beat single results

Hypertension management is rarely a one-and-done event. Cats age, conditions evolve, and medication needs can shift. Having consistent lab and blood pressure data over months (or years) gives your veterinarian a clearer picture of what’s stable and what’s changing.

For cats with CKD, monitoring might focus on kidney values, urine concentration, and protein in the urine. For hyperthyroid cats, thyroid levels and kidney values may be checked together because treatment can unmask kidney disease in some cases.

From an owner’s perspective, this can feel like “a lot of rechecks,” but it’s often the safest way to keep your cat feeling well while protecting organs from silent damage.

What treatment usually looks like (and what you can expect at home)

The goal of treatment is straightforward: lower blood pressure to a safer range and prevent ongoing organ damage. The path to get there can be a little individualized, depending on the cause, the severity, and whether target organ damage is already present.

Many cats do very well once treatment starts. Owners often notice improvements like better appetite, steadier energy, and reduced restlessness—especially if hypertension was contributing to how the cat felt day-to-day.

Medications commonly used

In many cases, veterinarians prescribe a blood pressure medication that relaxes blood vessels and reduces systemic pressure. The specific drug and dose depend on the cat’s needs and any underlying conditions.

It’s important to give medication consistently and not stop suddenly without guidance. If you miss a dose, ask your veterinarian what to do—recommendations can vary depending on the medication and the cat’s blood pressure history.

Side effects are possible with any medication, but many cats tolerate blood pressure meds quite well. If you notice lethargy, weakness, appetite changes, or anything that feels “off,” report it promptly so the dose can be adjusted if needed.

Treating the underlying cause (when there is one)

If hypertension is secondary to CKD, hyperthyroidism, or another condition, addressing that condition is a big part of long-term success. Sometimes blood pressure improves as the underlying disease is treated; other times, blood pressure medication remains necessary.

For hyperthyroidism, treatment might include daily medication, a prescription diet, or radioactive iodine therapy. For kidney disease, the plan may involve renal diets, hydration strategies, and managing nausea or appetite.

It can feel like juggling, especially at first. But once the routine is established—and once the cat starts feeling better—most owners find it becomes manageable.

Follow-up visits and rechecks: what’s “normal”

After starting medication, your veterinarian will usually recommend a recheck blood pressure appointment to ensure the dose is effective. This may be within a week or two for severe cases, or a bit longer for milder hypertension.

Over time, recheck frequency depends on stability. Some cats need more frequent monitoring if they have CKD, thyroid disease, or fluctuating readings. Others settle into a routine schedule.

Think of these visits as calibration. The goal isn’t just to lower the number—it’s to keep your cat comfortable and safe while protecting organs for the long haul.

When high blood pressure becomes an emergency

Some situations require same-day veterinary attention. Hypertension can cause sudden, dramatic symptoms—especially involving the eyes and nervous system. Acting quickly can make a real difference in outcomes.

If you’re ever unsure whether a symptom is urgent, it’s safer to call your veterinary clinic (or an emergency clinic) and describe what you’re seeing. They can help you decide the next step.

Sudden blindness or major vision changes

If your cat suddenly can’t see, bumps into objects, or seems panicked in familiar spaces, treat it as urgent. Hypertension-related retinal detachment can happen quickly, and early intervention may help prevent further damage.

Even if vision can’t be restored, controlling blood pressure promptly can protect the other eye and reduce the risk of additional complications.

Bring notes if you can: when you first noticed the change, whether both eyes seem affected, and any other symptoms like vomiting or lethargy.

Seizures, collapse, or severe disorientation

Neurological signs can be caused by many conditions, but hypertension is an important one to rule in or out. Seizures, sudden collapse, circling, or extreme confusion should be evaluated quickly.

Your veterinarian may check blood pressure immediately and recommend lab testing and imaging based on the findings. Stabilization comes first; deeper diagnostics may follow once your cat is safe.

If your cat has a seizure, keep them away from stairs or sharp edges, don’t put your hands near their mouth, and time the episode if possible. Then seek veterinary care.

Breathing difficulty or extreme weakness

Open-mouth breathing, rapid breathing at rest, or struggling to breathe are emergencies in cats. While not always directly caused by hypertension, high blood pressure can worsen cardiovascular strain in vulnerable cats.

Extreme weakness or fainting also warrants urgent assessment. These signs can point to heart issues, anemia, electrolyte imbalance, or neurological events—any of which may intersect with hypertension.

In these moments, the best move is prompt veterinary evaluation rather than waiting to see if it passes.

Practical tips for cat owners: partnering with your vet for long-term control

Living with a hypertensive cat can feel intimidating at first, but most owners quickly become confident once they understand the plan. The key is building a routine: medication, rechecks, and watching for specific signs.

It also helps to remember that hypertension is often manageable. Many cats live comfortably for years with controlled blood pressure, especially when underlying conditions are monitored and treated.

Keep a simple health log (it helps more than you’d think)

Write down a few basics once or twice a week: appetite, water intake (roughly), litter box changes, energy level, and any unusual behaviors. You don’t need a spreadsheet—just a note on your phone is fine.

This is especially useful for cats with CKD or hyperthyroidism where subtle changes matter. If something shifts gradually, you’ll catch it sooner and be able to describe it clearly at appointments.

Bring the log to rechecks. It can help your veterinarian decide whether to adjust medication or run additional tests.

Make medication time easier

If pilling is stressful, ask about options: flavored compounded liquids, smaller tablets, or administration tips. Some medications can be given with food; others may have specific instructions.

Try pairing medication with a positive routine—like a small treat afterward or a quiet cuddle session. Many cats respond well to consistency and will start to anticipate the routine.

If you’re struggling, tell your veterinary team. They’ve seen every medication challenge imaginable and can usually offer practical solutions.

Ask about screening schedules for senior cats

Even if your cat hasn’t been diagnosed with hypertension, senior wellness plans often include blood pressure checks—particularly if there’s any sign of kidney disease, thyroid disease, or vision changes.

Early detection is one of the biggest advantages you can give your cat. Catching high blood pressure before retinal damage or kidney decline accelerates can preserve quality of life.

If you’re unsure how often your cat should be screened, ask your veterinarian to recommend a schedule based on age, lab results, and risk factors.

Putting it all together: what to remember about hypertension in cats

High blood pressure in cats is common enough—especially in older cats—that it deserves a spot on every pet owner’s radar. The biggest challenge is that it can be silent until it causes sudden, serious symptoms like vision loss or neurological changes.

The encouraging part is that hypertension is usually treatable. With accurate testing, follow-up monitoring, and a plan that addresses underlying causes, many cats stabilize nicely and feel better than they did before diagnosis.

If you’re ever unsure whether your cat’s symptoms could relate to blood pressure, it’s worth asking your veterinarian about a check. It’s quick, non-invasive, and can reveal a lot—sometimes before your cat has to pay the price for a problem they’ve been quietly carrying.