People who have been treated for cancer often have lingering fatigue, but a new analysis of more than three dozen studies suggests regular walking or cycling might help boost their energy.
Patients' long-lasting tiredness 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 ways to ease cancer-related fatigue during or after treatment. But light-to-moderate exercise has the advantage of being something people can do on their own time, for little or no cost.
"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 of activity," she told Reuters Health — such as a 20-minute walk a couple of times each day.
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. 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, they reported this week in the journal The Cochrane Library.
"What we do know is there will be an appreciable difference; the average patient will get a benefit from physical activity," Cramp said. "The actual amount of reduction in fatigue is going to vary according to the individual."
For example, the team saw exercise-related benefits for people with breast cancer and prostate cancer, although not for those with the blood and bone marrow cancers 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 dose may be a better option, said Enderlin, who wasn't part of the research team.
Regular moderate exercise is one non-drug therapy recommended by the National Comprehensive Cancer Network.
Although it might seem intuitive to deal with fatigue by getting lots of rest and avoiding extra activity, that could lead to more loss of muscle mass and fitness, according to Cramp and Byron-Daniel.
One cancer specialist not involved in the new study said that along with reducing fatigue, a combination of moderate exercise and nutrition therapy may help women with breast cancer in particular lower their risk of recurrence. Women being treated for breast cancer tend to gain weight, said Dr. Roanne Segal, from the University of Ottawa in Ontario, Canada.
"We are now pushing… lifestyle programs which incorporate diet and exercise to get you to either maintain your weight or reduce your weight," she told Reuters Health.
But the most appropriate exercise program, Segal added, will depend on where patients are with their treatment and the details of their particular cancer.
Cramp emphasized that people will have different goals and abilities when it comes to exercise, and that they should discuss those with their doctor. And although most patients will be able to do some kind of physical activity, fragile bones and anemia might hold others back.
"Cancer patients should of course first talk with their doctor to see if it's safe to exercise," Enderlin told Reuters Health. "If it's felt they are safe to exercise, they should maintain a level of at least comfortable activity in order to keep up their endurance, to keep up their strength (and) to promote function."