The gym isn't all lycia and muscles. I am a member of our local pool/gym/leisure centre. Again, refered by the doctor and free for 12 weeks. A lot there are as old or older and more infirm than me. The staff are professionals there too and will not expect you to do bench presses or sit ups. There are exercise cycles and treadmills there which help lots of people who are not comfortable walking or cycling in public or, more likely in N Yorks, bad weather!