On Cold Showers

I like my gym -- convenient hours and locations, well-maintained facilities, boppin' tunes, weight-loss advice that in fact works (if you follow it), etc. etc. (did I mention the hairdryers? the hairdryers are great). But if I have one complaint, it's that sometimes the showers turn icy cold without warning. Why does this happen? And, more importantly, why does this happen to me? Well, as BoingBoing kindly explains, when the gym is crowded, no one is spared. Here's why cold water indifferently rains down on the svelte and not-so-svelte alike:

Christina Matzke at the University of Bonn in Germany and Damien Challet of the Institute for Scientific Interchange in Turin, Italy, used a mathematical model to show that shower temperature becomes increasingly sensitive to small changes in hot-water flow as the number of users increases. Thus in a youth hostel, for example, the showers often fluctuate between scalding hot and ice cold during heavy use. 

Annoying (even if that burst of cold water protects one's sanity).