Way Too Tired?

Resting May Hurt, Not Help, Say Those Unraveling The Mystery Of Fatigue

“Last month, leading physiologists gathered at the National Institute on Aging, part of the National Institutes of Health, and came up with a new paradigm of what happens in the brain and the rest of the body when a person has subjective feelings of fatigue. The new understanding ‘is a fundamental jump forward in the study of fatigue,’ said Dr. Luigi Ferrucci,
one of the conference organizers, and brings with it some good news for the tired among us.
Scientists are now convinced that fatigue has a real, molecular basis, and that at least two major biological processes are involved: An excess of natural chemicals called pro-inflammatory cytokines, which the body pumps out in response to infection. And sluggish mitochondria, the tiny organelles inside cells that make energy. Even if these two pathways work separately - and nobody knows yet if they do - the implications are profound. For one thing, unraveling these pathways could lead to new antifatigue drugs, said Ferrucci, who is also director of the Baltimore Longitudinal Study on Aging. For another, because both cytokine and mitochondrial problems get worse with excessive rest and improve with moderate exercise, it means exercise is an obvious, and readily available, remedy. A large body of research has already shown that exercise dampens down the ‘bad’ cytokines and boosts the number and efficiency of mitochondria. This doesn't mean you should go run a marathon if you've got the flu. Quite the contrary. In the acute phase of any illness, your body needs all its available energy to heal. But it does mean that, as soon as possible, you should get out and walk, even if it's just around the block for starters. A major part of the fatigue that accompanies many clinical conditions, including cancer, is triggered by ‘deconditioning,’ says William Evans, an exercise physiologist who is chair of nutritional longevity at the University of Arkansas for Medical Sciences. ‘As you become less conditioned’ which happens when an illness makes you lie around, ‘any activity becomes a higher percentage’ of your capacity. The good news, he says, particularly for people with cancer fatigue, is that ‘every study that has been published to date’ shows a positive effect for moderate exercise: ‘Training increases mitochondrial function to increase the capacity to use oxygen to make energy.’ So, how do you know when to rest, when to exercise and when to see a doctor? The guiding advice is to rest at the onset of an infection, and build in exercise slowly when you start to feel better. But so long as your doctor has ruled out major medical problems, you can find cheer in the news that feeling better, by exercising, is within your power. It does seem paradoxical, but in many cases, lying around because you're tired by may be exactly the wrong thing to do.”

http://www.boston.com/news/health/articles/2008/10/13/way_too_tired/