Starting to run in your fifties or sixties is one of the best things you can do for the decades ahead, and it is far more doable than it looks. Plenty of people take up running for the first time well into their sixties and seventies. The body that starts later just asks for a smarter, gentler approach.
After 50, muscle and recovery change. We lose muscle a little faster, and the body takes longer to bounce back between hard efforts. None of that stops you from running. It only shapes how you begin.
Start with walk-run intervals

The single best way to start after 50 is the walk-run method. It gives your body the adaptation time it needs and keeps the injury risk low.
Begin with one minute of easy jogging, then one minute of walking, and repeat for 20 to 30 minutes. Over a few weeks, let the running stretches grow and the walking shrink, until you are running most of the way.
Walk breaks are not a sign you are failing. They are the method, and plenty of lifelong runners still use them.
There is no prize for skipping this stage. The runners who last are the ones who built slowly.
Keep the pace easy enough to talk
Almost everyone starts out running too fast. The fix is simple: run at a pace where you could hold a conversation.
If you are gasping and cannot get a full sentence out, you are working too hard for a base-building run. Slow down, or take a walk break. That easy, conversational effort is exactly where your fitness is built, and it keeps the strain off your joints while your body adapts.
Let speed and distance come later, on their own. For now, easy and repeatable beats hard and occasional.
Build a little strength alongside

Running after 50 goes far better with some simple strength work in the week. Two short sessions are enough to support your stride, protect your joints, and keep the small injuries away.
Pay particular attention to strong feet and ankles, which do more than any shoe to keep an older runner steady and pain-free. A little work on your running form helps too.
Ease in, and respect recovery
The most common way to get hurt is doing too much too soon. After 50 recovery matters more, so leave a day between runs at first, and do not add distance and speed in the same week.
If something hurts beyond ordinary effort, rest it rather than running through it. Patience early is what lets you keep running for years, and the worry that running will wear out your body as you age is mostly unfounded when you build sensibly.
When to check with a doctor
This is general information, not medical advice. If you have been inactive for a while, or you have a heart condition, joint problems, or another health concern, see your doctor before you start. A quick check is worth it, and it is usually a green light.
The bottom line
Starting after 50 is not about catching up to who you were at 30. It is about becoming a runner for the years you have ahead. Walk-run gently, keep it easy, build a little strength, and let time do the rest.