In the face of this research, long-standing skepticism about the possibility of "exercise overdose" is softening among many sports physicians.

WSJ: The Exercise Equivalent of a Cheeseburger?

She also had a revelation while seated in front of one of the dioramas (my recollection is that it was the one of salmon-hunting Alaska brown bears standing seven feet tall): that the only reason we exercise dominion over the Earth, and creatures bigger and stronger than us, is because of our larger brains.

WSJ: At 88, a World Full of Wonders

But Andrew, the Rugby Football Union elite rugby director who was standing in as tour manager for Martin Johnson, insisted the tour had been a worthwhile exercise ahead of the naming of a 32-man elite squad on 1 July.

BBC: Andrew upbeat despite series loss