I did a DNA search on my son's mtDNA, which is 'H', and the most wide spread in Europe. I came across an article in the Lancet about survival advantages in Haplogroup 'H' people. Persons from haplogroup 'H' are twice as likely to survive infections such as MRSA and pneumonia and a very high survival rate for sepsis when compared to other haplogroups.
No doubt, this reflects something from our past and may explain why mtDNA haplogroup 'H' is the most wide spread in Europe today...they're the survivors, huh?