Can meditation help prevent the effects of ageing?

Meditation won't reduce stress in those people whose minds race in circles about their problems and worries whenever they have an idle moment, such as when they wake up at 3 in the morning with a cold sweat and a racing pulse. If you want stress-free meditation, you need to be a low-stress individual to begin with. (I suspect these are the types who are drawn to meditation.) If you have stress from problems, those will become like the "white elephant" that you're not supposed to think about.

Quick, close your eyes, and let your mind wander freely: but whatever you think about, do not think about your problems! Go!

I think the best way to eliminate a stress is to have a hobby which occupies your mind so that you cannot simultaneously focus on it and on stressful problems. And, of course, manage those problems and keep them to a minimum.

Hobbies are a form of meditation: and even when when you're away from them, because you still think about them. In your min you do planning related to your hobby, and solve problems, which creates a deep focus which is like meditation, which you can enter into whenever you have a spare moment, and which is free of the "white elephant" problem.

Simply meditating by letting my mind wander about nothing would be an unacceptable waste of time to me, and the mystical/religious aspects of it are completely deplorable to me: the article is spot on the money with its remark:

"“People are very uncomfortable with the concept of meditation,” notes Blackburn. She attributes this to its unfamiliarity and its association with spiritual and religious practices."

I've read about hippies who wasted their whole lives by doing transcendental meditation. Instead of pursuing something real, they just vegetated away years and years, sitting cross-legged among a group of others doing the same.

Look at what some Buddhist monks do: gardening, or upkeep of a temple: replacing old wood or bamboo with new. They don't just sit around with their eyes closed, doing nothing.