I don't agree with the "lack od physical strength/stamina" arguement!!! Have you seen the 60 year old rickshaw pullers toiling under oppressive humid conditions. These guys must have some of the strongest calf muscles, backbones, arms, and abs in the whole world. Not an ounce of fat on them! The rickshaw pullers in Bangladesh are the supreme example of strength, stamina, and hardwork that Bangladeshis are capable of if they put their minds and bodies to it.