Cat Health Log: What to Track and the Red Flags to Watch (2026)

Cats are famously good at one thing besides sleeping: hiding illness. It’s an evolutionary leftover — a sick cat in the wild is a target, so cats mask pain and weakness until they physically can’t anymore. By the time a cat acts sick, the disease behind it has often been progressing for weeks or months.

That’s the case for a cat health log in one sentence: you can’t out-observe a cat’s instincts, but you can out-record them. Here’s what belongs in the log, the thresholds that should trigger a vet call, and how to keep the whole routine under five minutes a week.

The Six Things Every Cat Health Log Needs

1. Weight — the master signal

Weight change is the closest thing to a universal early-warning system in cats. Hyperthyroidism, kidney disease, diabetes, dental pain, digestive disease — nearly everything moves the scale before it moves behavior.

• Weigh weekly. Step on a scale holding the cat, subtract yourself, or use a baby scale for precision.
• Red flag: losing 5% of body weight (that’s just 200 g for a 4 kg cat) over a month, without a diet change. That’s a vet visit, not a “keep watching.”

2. Water intake

Cats evolved from desert animals — they’re naturally light drinkers. When a cat starts drinking noticeably more, take it seriously.

• Note refill frequency, or measure what you pour versus what’s left daily.
• Red flag: more than ~100 ml per kg of body weight per day, or any sustained visible increase across a week. Increased thirst is the classic early flag for chronic kidney disease and diabetes — the two heavyweight diseases of senior cats.

3. Litter box output

Nobody’s favorite entry, but the highest-stakes one for male cats.

• Track visit frequency, urine clump size, and stool quality.
• Red flag: straining with little or no urine is a same-day emergency in male cats — a urinary blockage can be fatal within 24–48 hours.
• Red flag: diarrhea beyond 48 hours, blood, or defecating outside the box repeatedly.

4. Appetite

• Log meals as finished, partial, or skipped — that’s all it takes.
• Red flag: a cat that eats nothing for 24 hours (or eats poorly for 48+) needs a vet. Cats are uniquely vulnerable to hepatic lipidosis, a liver complication triggered by not eating, which turns “just being picky” into a serious illness of its own.

5. Grooming and coat

Cats spend up to half their waking hours grooming, which makes grooming changes unusually informative.

• Overgrooming (bald patches, irritated skin) → stress, allergies, parasites, or pain in the licked spot.
• Undergrooming (greasy, matted, dandruffy coat) → arthritis (can’t reach anymore), obesity, dental pain, or feeling unwell. In senior cats, a scruffy coat is one of the most common first signs of chronic disease.

6. Behavior and mobility

One line a day: hiding more? Sleeping in new spots? Hesitating before jumps? Vocalizing at night? Jump hesitation in particular is textbook early arthritis — which affects the majority of cats over 10, and which most owners never report because “she’s just getting old.”

The Weekly 5-Minute Routine

Every Sunday:

1. Weigh and log it.
2. Hands-on scan — run your hands over the whole body: new lumps, mats, tender spots, ribs too easy or too hard to feel.
3. Teeth and breath check — lift the lip: red gumline, tartar, or foul breath mean dental disease, which affects most cats by age 4.
4. Review the week’s log — anything drifting: appetite, water, litter, energy?

Ten minutes before an annual vet visit, skim the log for the year’s trends. You’ll walk in with the exact history vets wish every owner had — and if vaccines are part of the visit, your cat vaccination schedule should be in the same place, not on a paper card in a drawer.

Why Trends Beat Snapshots

A single data point — “she left some food today” — means almost nothing. Cats have off days. The value is entirely in the pattern:

Single observation	Same observation as a trend	What it might mean
Left food at dinner	Appetite down 6 of last 10 days	Dental pain, nausea, kidney disease
Drank a lot today	Water refills doubled in 2 weeks	Diabetes, kidney or thyroid disease
Big urine clumps	Clumps growing for a month	Diabetes, kidney disease
Skipped a jump	Avoids counter entirely now	Arthritis, injury, weight gain

This is exactly what a log is for. The individual entries are trivial; the accumulated curve is diagnostic gold.

Paper Card vs. App

You can absolutely run a cat health log on paper. What an app adds: automatic weight charts, reminders so weekly weigh-ins actually happen, medication tracking with dose-by-dose logging, timestamped entries the whole household can add to, and a PDF export your vet can skim in thirty seconds. PokiPaw includes a cat-specific Health Score that rolls weight, vaccination status, and activity into one at-a-glance number — useful for spotting quiet drift even when no single log entry looks alarming.

Start With Just Two Numbers

If six categories feels like a lot, start with the two highest-value signals: weekly weight and daily appetite. Those two alone catch a remarkable share of feline disease early. Add water and litter tracking once the habit sticks.

Your cat will keep hiding symptoms — that part’s not negotiable. Whether you have the data to see through it is.

Download PokiPaw to keep your cat’s weight chart, health records, vaccines, and daily log in one place — and know what “normal” looks like before something isn’t.