I didn't realise just how totally out of shape I was. I haven't ridden at all since perhaps October last year, but even before then my 'riding' was not exactly frequent. I've been pretty fit since my early twenties until about 4 years ago, when I became a lot less active. However during the last year, my lifestyle has become extremely sedentary.
I've just finished building up a few bikes for all-purpose use and took the opportunity to take one out for a spin today on my way to work. This was the first time I've ridden a bike in at least 5 months or so. There was a headwind and I was riding a slightly inappropriate bike for the task, but it wasn't out of the ordinary to me... I used to commute on freerides.
I got three-quarters of a mile from my house at what I thought was my usual pace. That is, until I started to lose all strength in my legs, my heart started pounding like a jackhammer and I started seeing stars. I nearly fell off my bike, but managed to swerve safely to the side of the road and stagger off onto the pavement, where I sat clutching my chest. My heart was racing like I'd never had happen before, and I actually had a pain in my chest. It wasn't 'heart attack' pain but man it was scary. I rode back home very slowly, and took the car after recovering.
Lesson learned: Start slow!