How fast does a "normal" person gain stamina?

I know I can feel improved fitness on a third try at something.

Long non-answer:

I don’t think you can measure the requirements for progress in kilometres. For example, it can make a world of difference whether you cover the same distance by running 10 metres daily for 1000 days, or 1 kilometre daily for 10 days. Or half a kilometre a day two days a week for 10 weeks.
If you follow a schedule, then an experienced trainer might be able to tell you for how long you’ll need to follow it before you can expect to have doubled your stamina.

And as you say, normal people don’t exist. Different people will have a different metabolism and cardiovascular system and whatnot. A doctor might be able to tell you what effects yours will have on your development, and may even be able to estimate how much it will affect your progress.

But I’d say if you really want to know, there’s only one feasible way to find out: work out, and take notes. Then by the time you can run twice as long before having to stop, look back and see how long it took you. :)

@SebastianUllman: On which side of the normal mark of the Bell curve do you fall?

I used to measure my power walking stamina by telephone poles. That way I knew I was walking a little further every few days. It was both a simple and workable system.

Depends on how hard you work at it.

After a long hiatus it takes me about 3 – 4 weeks to regain top form and stamina. Even starting from scratch I feel anyone can double their stamina in that amount of time after 8 weeks you should hit full stride and be able to maintain an ability to kick it out.

stamina in bed??

the more you do the faster it goes [as long as you give your body adequate rest in between]. You will see increased performance gradually. Measurements like those suggested by @gailcalled are helpful. I think it takes longer if you are older.

Talk to your doctor and personal trainer. The amount of change is dependant on the amount of effort put into it, and your overall health to begin with.

@gailcalled : Well, I’m on the lower section of “normal” on the BMI anyway, and my metabolism is very high. Though I have fairly good possibilities to grow muscle fast, although not bulky ones. I’m slim and don’t have to run many times to reveal abs. Hope that answer your q.

One day at a time.