You may think of a cat nap as a short snooze, but cats are actually super-sleepers, often slumbering for 12 to 18 hours a day.

That's healthy for them, but for humans sleeping more than an hour while the sun shines can be a sign of developing liver problems, according to a study in BMC Gastroenterology.

Researchers found that compared with people who don't nap, those who slept for 60 minutes or more during daytime have a 200% greater risk for nonalcoholic fatty liver disease (NAFLD) — a potentially serious condition that afflicts an estimated 25% of U.S. adults, and often goes undiagnosed.

If you're taking hourlong snoozes during the day, inform your doctor so she or he can check for NAFLD, and if necessary help you manage it.

From long naps to long COVID-19. Ten percent to 30% of people who've had COVID-19 will develop long COVID-19. Those people have a 63% greater risk of heart attack and a 52% greater risk of stroke than those who have never caught the virus.

The Centers for Disease Control and Prevention says breathing exercises; sitting aerobic and strength-building exercises, and then walking and standing workouts; and the use of antihypertensive medications can help reduce your risks.

Talk to your doctor about an individually tailored rehabilitation routine.