How to come up with article topics for a specific demographic?

I need to generate about 100 health/fitness article ideas that are relevant to men and women above 50 years old who want to improve their health.

Just off the top of my head, I can come up with broad areas like back pain, stretching, improving your balance, natural supplements, etc..

But how can I generate an actual list of keywords or article ideas that fit this demographic and topic? Are there any tools you guys would recommend?

Find blogs that already cater to those demographics and enter their urls into Google Keyword Planner Tool

GKPT has a neat feature where you can reverse engineer your competitors' targets

I use scrapebox to harvest keywords from my competitors

Have you tried LongTailPro? They come with a free trial. I’ve gathered a lot of my content ideas from there.

Google Keyword Planner is the best place to begin with.