Fitness Plan for Senior Citizens

You don't say what your current fitness level is, but I'll assume that you're a beginner.

1. Start with something easy, like walking. Just do what you can and try to increase speed and/or distance daily.
2. Make sure you get up and move throughout your day. Even if it's just to walk outside to get the mail, for example. Be aware when you are sitting too long.
3. Do some light lifting with 2-5 pound dumbbells--however much weight you can handle and increase the weight as you are able. If you have access to a gym, do the circuit if they have one, or take a class. There are a lot of great classes out there for seniors which will help you get your foot in the fitness door.
4. The most important thing is for you to know that even though you are in your sixties THERE ARE NO LIMITS. I learned that from a 65 year old spinning instructor who did 100 mile bike races up and down mountains for the fun of it on weekends. I went from being 50 pounds or so overweight, sedentary, and never running a mile in my life to being able to run a half marathon and lifting weights on the squat rack. I'm 56.
5. Read the book "Younger Next Year for Women" by Chris Crowley. It will give you the insight into how aging should really work and how you can be 'fit, strong, and sexy' into your nineties.