Sorry to hear about your travails rhrgrt---but OP says specifically that biking does help her, and apparently she does it well enough that it doesn't hurt her.
Biking is Not a symptom. Biking is a treatment. it gets the rider out of doors, often in the sun, and out of the same stale environment. it forces the brain to deal with immediate situations, giving less time and space to devote to depressing thoughts and feelings, and can stimulate the release of endorphins.
Plenty of folks have found that exercise, even just a stroll around the neighborhood, can be therapeutic, and more vigorous exercise, more so. And plenty of people really like riding bikes.
I'd say OP doesnt;'t need scare stories right now ... maybe we should get over ourselves and focus on her needs, and try to help her in this tough time for her, eh?
And TimothyH---I agree faith is the highest thing ... but saying "What happens if you are crippled" is really selfish and pushy and negative. It is not at all supportive. I cannot imagine a wise or holy man, or any one with love in his or her heart, saying that to someone in this situation.
Maybe this is all message-board BS and none of it matters. Maybe OP is a troll, who knows?
I tend to think there are times and situations where wee need to put ourselves aside and focus on others, when our compassion should override our selfishness and our desires to make our own points.
Let's wait until the OP is on her feet, in the groove, and loving life, with all its hardships, before we tell her all our horror stories or try to force our beliefs on her, perhaps?