The long-lasting tiredness of cancer patients has been blamed both on the cancer itself, including cancer-related pain, and on the effects of treatments such as chemotherapy. Prior studies point to talk therapy, nutrition counseling and acupuncture as possible remedies.

But light-to-moderate exercise has the advantage of being something people can do on their own time, for little or no cost, said the researchers, whose findings appeared in The Cochrane Library.

"We're not expecting people to go out and be running a mile the next day," said Fiona Cramp, who worked on the analysis at the University of the West of England in Bristol.

"Some people will be well enough that they're able to go for a jog or go for a bike ride, and if they can, that's great. But we would encourage people to start with a low level."

Cramp and her colleague James Byron-Daniel pooled findings from 38 studies that directly compared more than 2,600 people with cancer-related fatigue who did or didn't go through an exercise program.

The majority of that research looked at women with breast cancer and the type of exercise program varied, from walking or biking to weight training or yoga. More than half of the studies included multiple exercises or allowed participants to choose their own type of physical activity.

The amount of prescribed exercise ranged from two times per week to daily workouts, lasting anywhere from ten minutes to two hours, depending on the study.

When they combined the results, the researchers found physical activity both during and after cancer treatment was tied to improved energy. In particular, aerobic exercise such as walking and cycling tended to reduce fatigue more than resistance training.

"What we do know is there will be an appreciable difference; the average patient will get a benefit from physical activity," Cramp said, though the actual benefit will vary.

For example, there were exercise-related benefits for people with breast cancer and prostate cancer, although not for those with leukemia and lymphoma.

"Some of the hematologic patients may not have the reserves to always tolerate the aerobic exercise," said Carol Enderlin, who has studied fatigue and cancer at the University of Arkansas for Medical Sciences in Little Rock.

"They do not always have the oxygen carrying capacity, for instance," because the disease and treatment affect blood cell counts. For those people, non-aerobic exercise or exercise at a lower does may be a better option, added Enderlin, who was not part of the research team.

SOURCE: bit.ly/TMV6SC

(Reporting by Elaine Lies)

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