Marathon runners!

[Digger]

Well, according to this article on the beeb Linky you may well end up significantly shorter than when you started. I can only imagine its due to compression and crushing of muscles, bones etc

"An amazing sixty percent of a club runner's muscles will suffer some damage in a marathon with the constant pounding leading to a loss of about 2cm in height."

No thanks, I am short enough as it is

 

[shodan]

I believe its down to the compression of the joints and the vertebrae on the spine. Its not unusual (to be loved by anyone...) to be taller in the morning than in the evening anyway...