@SamaHoole
You are not too old to build muscle. The people who told you otherwise have never read the study that settles it. In 1990, researchers took ten frail nursing-home residents with an average age of 90 and put them on heavy resistance training three times a week. Real load, taken close to what they could manage. No chair aerobics, no resistance bands the colour of a boiled sweet. Actual weight. Eight weeks later, among the nine who finished, strength had climbed by an average of 174 percent. Their thigh muscle had grown. Their walking speed improved by nearly half. Two of them put their walking sticks away. One resident who could not stand from a chair without using their arms got up unaided. Average age in the room: 90. Oldest: 96. If you think ten people is a thin reed to lean on, the same researcher ran it again four years later as a proper randomised trial, a hundred nursing-home residents this time, and the strength gains held at 113 percent. The frail and the ancient kept building muscle every time anyone bothered to test it. Now sit with what you have been told instead. Take it easy. Mind your back. You don't want to overdo it at your age. Stick to walking. A nice gentle swim. Don't lift anything heavier than the kettle. Every one of those instructions was handed to people more capable than the nonagenarians in that study, and it made them weaker. Muscle responds to load. It does not ask your age before it grows. The 70-year-old who picks up something heavy twice a week is building tissue the same way the 25-year-old is, just from a different starting line. Slower, smaller numbers, but the machinery still works, and it keeps working into your nineties whether anyone gave you permission or not. Old age was never the thing that made you weak on its own. A lifetime of being told to sit down and protect a body that was begging to be used did far more of the damage. Pick something up. Put it down. Do it again next week with a bit more. You have decades of evidence and a nursing home full of nonagenarians on your side.