The drop in apolipoprotein II in the long walkers was matched by a rise in the blood level of apolipoprotein I, a "good" fat that is associated with unclogged arteries.

The major component of high-density lipoprotein (HDL, sometimes known as "good cholesterol"), apolipoprotein A-I, consists of a kinked helix about 12.5 nanometers in its longest dimension.