Went for my first run today for 2 weeks - during which time I have eaten and drank well (but not too excessively) & had a head cold. I ran 4 klms at 30 seconds per K slower than what I did 14K two weeks ago - and it nearly killed me . No lungs, stiff calves - sweating profusely -- couldn't have gone any further if I had wanted to!!! I can see that it is going to take me a bit longer than I thought to become once again a finely honed atheleet!!