Correct answer: 1, fruit flies that are exposed to the cold during the first two weeks of adulthood are better able to withstand other sources of stress throughout their lives. They even live longer.
We are familiar with the adverse effects of extremely low temperatures on the human body, and we know of some of the positive effects that the cold can have when storing organs prior to a transplant and on an oxygen-deprived brain. But maybe the cold hasn’t yet revealed all its secrets.
Researchers from the French National Center for Scientific Research (CNRS) have shown that fruit flies exposed to intense cold during the first two weeks of their adult lives tended to live longer and were better able to handle severe stresses such as heat and fungal infections. Another study, published in 2016 in Biogerontology, demonstrated that this resilience lasted throughout their (short) life.
So should EPFL students be advised to go without their coats this winter in order to live a long and healthy life? Not just yet: the researchers have obviously not made that sort of link. But they are trying to figure out the mechanisms underlying their findings. Other sources of moderate stress – such as heat or several G’s of acceleration – also tend to make fruit flies more resilient. According to the researchers, the fact that this kind of acceleration does not occur in the natural world – it is produced by putting flies into tubes and then centrifuging them – would suggest that there is some sort of overarching mechanism at play. In other words, there may be some kind of signaling pathway that is totally unrelated to the fly's evolution and that could therefore exist in other animals, including mammals. They also note that “moderate stress may be worth exploring for therapeutic purposes or to prevent the negative effects of aging.” EPFL students stressing out about their upcoming exams may at least find comfort in the thought that this could make them live longer.
Article in Medecine/Science: "Mild stress as a means to modulate aging: from fly to human?"