Yes absolutely , in autumn , winter it happened to me many times. One just last week tapering week for an half marathon
thursday begun a strep throat than after 4 days cold and headache for other 3 days feeling very weak , that I barely walked
and the last workouts before the tapering was excellent so I was in good shape. I tried the Half with my goal pace but at 12 K
, had no power in my legs to go on and so I just drop out. But I also notice and there's some study on it
that it depends a lot from Km/week. They did a study on many runners an saw that runners that do more than 90k/week
are more likely to get sick than runners that do 60 or 70 k per week.
I always wonder how elites than run 180 k per week and prepare only two marathon in a year can always be in perfect shape
to the race. Think to Kipchoge consistency over the years in the many marathons he runs and win.It's incredible!! Apart from running talent that somebody can have.
Thats' the real crazy thing ! To go year after year in that hard training regime , with a 5% body fat and never get sick.
Maybe at 2400 m of the Rift Valley there are not so many flu or cold virus like in our town and cities