Cycling issue

Hi,

not so active here now as 4 years along my cancer journey, well, I will be on 13 May2017.  My experience of the Robotic Op and subsequent treatment is outdated, as advances continue to be made, thank goodness.

So, here is where I need help.  I was on a course recent,y where I was required to ride a bicycle for about 40 minutes.

Now, I have cycled all my life.  Used to part drive/part cycle to work for many years, cycling 12 to 16 miles each depending on here I parked.

Used to cycle at weekends for fitness, 15 to 20 miles.  I cycled.

I knew in advance I would have to cycle.  I selected my bike.  I got the lid on.  I got the Hi-vis on.  I stood by the bike, for an age. I could not get on the bike. That is when the instructor came to me, and asked if I had a problem.  I told him of my past and the operation, and my "staging".

My diagnosis was initially T2, upgrade after pathology, DAMN YOU PATHOLOGY, to T3, so touching the wall.

I was scared that there may be a stray cancerous cell somewhere in me, somewhere down below, that cycling may dislodge and send around my body

Is that fear irrational?  At the moment I am so fortunate, life is so good.  I do not want to jeopardise that.

dave