In fact, I had an opportunity to live in Barcelona for three months and while a lot of businesses do close down from noon to three, I got the impression that people were not using that time to sleep, and that the idea of siesta in Catalunya is on the decline.
Same for a more rural area of Mexico (Toluca surroundings), they also did siestas there.
Googling a bit, acording to Time magazine, siesta was struck down in Mexico in 1944, so it's more a myth than reality now I guess (probably subsists in some more rural areas).
http://www.time.com/time/magazine/article/0,9171,850501,00.h...
My impression was that siesta still persisted in some countries, but that it tends to disappear as they conform to western work hours, and, as the Time article states, it does involve four commutes instead of two, so it's not workable in urban areas (btw, people who siesta still work the same amount of hours, I'm not saying they work less).
Regarding the article, I guess one should just do what works for them (their body). Some people find it necessary to get 8 hours of sleep, and some are okay with six.
