Getting old never looked so good.

While tech entrepreneurs and biohackers race to rewrite the rules of longevity, there are everyday telltale signs you’re aging well without a health tracker or blood tests.

Rather than simply avoiding disease, getting older well involves a more holistic view of physical, mental and emotional well-being, according to Dr. Tina Sadarangani, PhD, a board-certified adult and geriatric nurse practitioner.

“Aging well in your 40s and 50s doesn’t just mean looking younger,” Sadarangani told The Post. “It also means feeling and functioning at your best.”

And on the flip side, there are warning signs that things may be heading south once you approach the mid-century mark.

“The 40’s and 50s represent a critical window when many age-related changes first become apparent or accelerate,” Emmanuel Osei-Boamah, a board-certified geriatrician and physician with Mercy Family Care in Baltimore, told The Post.

1. Maintaining strength

Maintaining your strength and endurance makes a big difference as you get older.

“Someone who can climb stairs, carry groceries, get up from the floor, and stay active is more likely to remain independent as they age,” Sadarangani said.

Osei-Boamah agrees, adding that aging well “is characterized by the preservation of functional independence.”

He also added that walking speed, balance, handgrip strength and how fast you can stand up are also good indicators of good aging.

Conversely, becoming weaker is a sign that one may not be aging as well. Signs of weakened strength can include reduced grip strength, difficulty with tasks requiring balance or coordination and new joint stiffness or pain, signs of osteoarthritis.

2. Staying socially connected

Research has determined loneliness to be a public health threat among the likes of obesity and smoking — and the health risks are well-documented, especially for older adults.

“People who maintain close relationships, participate in their communities and have a sense of purpose tend to experience better physical and cognitive health in the long-term,” Sadarangani said.

We should also continue to try new things with each passing year, since those who learn new skills or take up new hobbies are “building cognitive reserve by challenging their brains.”

Social connections and activities can also help people pay attention to any changes in mood. Sadarangani notes that persistent sadness, anxiety or loss of interest shouldn’t be taken as normal signs of aging.

“Depression and anxiety become more common during this stage of life and deserve the same attention as high blood pressure or diabetes,” she said.

3. Recovering from setbacks

Can you recover from sickness, surgery and emotional changes? Getting older causes a decline in the ability to maintain internal stability or homeostasis — so if you’re not struggling too much here, you’re on the right track.

“People who are aging well recover well after… a stressful life event and return to their previous level of function,” Sadarangani said. “This is often a better indicator of health than chronological age.”

4. Being proactive about health

Your 40s and 50s bring on a slew of internal changes, according to Osei-Boamah, including higher blood pressure, increased risk of irregular heartbeat, hormonal changes, cognitive decline, age-related hearing loss and increased possibility of glaucoma.

But you’re aging well, you’re staying ahead of your health and going to the doctor regularly.

“Keep up with recommended screenings; manage blood pressure, cholesterol and blood sugar; stay current on vaccinations; and address hearing, vision and sleep problems before they interfere with daily life,” Sadarangani said.

And you don’t want to wait until you’re getting up there to get started.

“It’s important to remember that your health at 40 significantly influences your health at 60, which in turn affects your health at 80, and so forth,” she added.

5. Sleeping well

A good night’s rest is fundamental to overall health, affecting everything from our brains to our hearts to our nervous systems.

“Consistently getting seven to nine hours of restorative sleep supports memory, mood, immune function and heart health,” Sadarangani said.

And if you’re not getting a full night or quality shut-eye, it shouldn’t be accepted as a downside of getting older.

“People often accept poor sleep as a normal part of aging, but chronic insomnia, untreated sleep apnea or waking up exhausted should be evaluated, not ignored,” Sadarangani added.