I've recently started doing aqua aerobics again and it's brilliant - the water helps and you'll probably find that the group will be mainly of the GN age group. It really doesn't matter what sort of exercise you take up, it will do you good, find you new mates and unless you go to a snobby gym, the staff and fellow exercisers will encourage you to enjoy getting fit. If you've currently got health issues, check with your GP, but you'll probably have a local "Gentle Exercise" group, which pushes you to do what you can. And I've just taken up yoga - my mum started at 70+ and got quite good at it, but I have arthritis, and had an elbow replacement so can't straighten my arm and although I'm already getting better, and my balance is definitely improving, most of the moves are always going to be beyond my ability. Just do what you can. I approve wholeheartedly of Petra's suggestion of Youtube videos - you will discover what sort of exercise suits you, without embarrassing yourself - maybe Tai Chi could be a good starting point, since it builds your sense of balance and isn't over-strenuous. Good luck and enjoy!