How Exercise May Help Survivors: The Latest Research
- In Brief: Overweight and Label Confused
- Sit...Sit...Sitting May Shorten Your Life
- Successful Weight Loss: Cut Fat and Up Exercise
- US Getting Enough Nutrients Overall, But Deficiencies Among Us
How Exercise May Help Survivors: The Research
Fatigue, joint pain, lymphedema, depression, weight gain, cardiovascular disease, diabetes – this litany of ills is only a partial list of what cancer patients may experience during, and years after treatment.
A growing and consistent body of research suggests exercise may help.
The research on the benefits of exercise to cancer survivors was summarized by AICR grantee Melinda Irwin, PhD, at the recent American Association of Cancer Research annual conference. Irwin, a researcher at Yale University, is one of a cadre of experts investigating how exercise helps survivors, and how to help survivors exercise.
One key finding for cancer survivors was reached by a group of experts in 2010: avoid inactivity. We've written about that recommendation before; you can read more here.
As Irwin noted, most of the studies have been conducted among breast cancer patients. There's a fair amount among colorectal and prostate cancer survivors, but other cancers are not as well studied. Here are highlights of the research Irwin covered:
- Exercise can improve survivors' quality of life: A lot of the research in this field started with quality of life, using questionnaires to ask survivors about such issues as depression, anxiety, and fatigue. More recent analysis of longer trials have shown improvements in many quality of life indicators. The few trials that looked at women who did both resistance training and aerobics showed even more improvements than aerobics alone.
In many of these trials the exercise was supervised, which means it's possible the "the attention effect" may have affected the results. Future trials are accounting for this.
"Studies have shown resistance training is not associated with exacerbating breast-cancer related lymphedema. More recent studies even suggest regular resistance training may lower the risk of lymphedema occurring."
- Exercise can help cancer-related fatigue. The most common symptom of survivors, this persistent tiredness interferes with daily life activities and can occur years after treatment. The literature on exercise helping cancer-related fatigue both during and after treatment is among the strongest in the field, said Irwin.
- Exercise does not exacerbate – and may improve – lymphedema. Years ago, health practitioners advised women to rest for fear exercise would worsen this condition common in breast cancer patients. In lymphedema, a build-up of lymph fluid causes part of the arm (or leg) to swell, making it painful to use and more likely to get infected.
Studies have shown resistance training is not associated with exacerbating breast-cancer related lymphedema. More recent studies even suggest regular resistance training may lower the risk of lymphedema occurring.
- Studies suggest exercise may lengthen survivors' life, prevent recurrence. Over the past decade, a growing number of observational studies have shown that the most active survivors have approximately a 50 percent reduced risk of dying from any cause during the course of the study compared to those who are inactive. Studies looking at breast and colorectal cancer specifically have found that survivors who exercise regularly lower their risk of recurrence and dying from the disease by 30 to 50 percent.
This makes sense, said Irwin, because exercise appears to reduce insulin and other factors linked to breast cancer development. In Irwin's The Yale Exercise and Survivorship Study, for example, levels of insulin and insulin-like growth factor (IGF-1), were increased in the breast cancer survivors exercising less than 20 minutes per week and lowered in the women exercising more than 150 minutes weekly. Other studies, focusing on strength training and/or aerobics made similar findings.
There's a lot more research needed to understand the effects and mechanisms behind exercise helping survivors, said Irwin. How exercise affects specific high-risk populations, the most effective types of exercise, and mechanisms are just a few areas of current study.
But with all the positive findings on exercise and survivorship, one key research area is to figure out how people can adopt and maintain physical activity after a cancer diagnosis.
"We see that more than 50 percent of women are not meeting the recommended amount of aerobic activity, only a couple years after diagnosis," said Irwin in her presentation. Given that many people over-report, "if we looked at this more objectively, it would probably be down to 10 percent."
For oncologists, Irwin suggests they strongly recommend their patients start or maintain their exercise program. "An oncologist's recommendation means a lot to a patient," she notes. Patients can contact their local YMCA to find out of they offer a free exercise program for survivors. They can also look for a local certified cancer exercise trainer at the American College of Sports Medicine site.
More than half of consumers around the world say they are overweight – up from 50 percent three years ago with dieting and exercise by far the most popular methods to lose weight no matter what part of the world residents live, finds a recent survey conducted by Nielsen.
The Nielsen survey polled more than 25,000 consumers online in 56 countries throughout Asia Pacific, Europe, Latin America, the Middle East, Africa and North America.
The survey also showed that the majority of respondents have trouble understanding nutrition labels on food. Only 52 percent answered that they understood the labels "in part", and 7 percent did not understand them at all. In North America, almost two-thirds of respondents said they were overweight with slightly over a third saying they only understand nutrition labels in part.
Sources: Battle of the Bulge & Nutrition Labels: Healthy Eating Trends Around the World. January 2012
Sitting too much may lead to an earlier death, regardless of weight or how much you exercise, suggests a large new Australian study published in the Archives of Internal Medicine.
The study attributed sitting to 6.9 percent of the deaths during the course of the study.
In the study, researchers asked a quarter of a million participants how much they sat every day on average. Participants were ages 45 and older.
Overall, the more people reported sitting the greater their risk of dying during the three-year study. Compared to those who sat fewer than four hours a day, those who sat 11 or more hours a day were at a 40 percent increased risk of dying. The results take into account many possible factors that might influence the findings, including participants weight, physical activity, sex and age. The protective effects of sitting against all-cause mortality held for individuals who were healthy at the start of the study and those with cardiovascular disease and diabetes.
Those who exercised the most – over five hours a week – have the lowest mortality rate among all the groups. But even among these exercisers, the more they sat the greater their risk of an earlier death.
Sources: van der Ploeg HP, Chey T, Korda RJ, Banks E, Bauman A. "Sitting time and all-cause mortality risk in 222 497 Australian adults." Arch Intern Med. 2012 Mar 26;172(6):494-500.
Close to half of obese dieters succeeded in losing at least five percent of their weight, at least for the short term, with the most common strategies linked to weight loss focusing on eating less fat and exercising, according to a study published in the American Journal of Preventive Medicine.
Liquid diets, nonprescription diet pills, and popular diets had no association with successful weight loss. The study defined success as losing at least 5 percent of body weight. In all, 20 percent of those trying to lose weight reported losing at least 10% of their body weight, with 40 percent of the dieters losing at least 5 percent of their body weight.
In the study, researchers used data from approximately 2,500 obese men and women who had all tried to lose weight the previous year. Participants, who were part of The National Health and Nutrition Examination Survey, were shown a list of 14 weight loss strategies and chose which they had used.
The most common strategies associated with both a 5 and 10 percent weight loss were eating less fat and exercising more. Only a small proportion of the participants used prescription weight loss pills and joined commercial weight loss programs but these also linked to a 5 percent and 10 percent weight loss, respectively.
One limitation to the study is that it only looked at losing weight, not maintaining weight loss, note the authors.
Sources: Successful Weight Loss Among Obese U.S. Adults. American Journal of Preventive Medicine May 2012, Vol. 42, No. 5.
The Centers for Disease Control and Prevention report measured 58 indicators of diet and nutrition among participants taking part in national health survey. This is the second report measuring indicators, and shows that nutrient levels have remained steady from 1999 to the latest round of testing in 2006.
Key findings include:
- Vitamin B6, iron, and vitamin D are the nutrients with the highest rate of deficiency overall.
- Vitamins A and E, and folate have the lowest rate of deficiency (less than 1%)
- Vitamin D deficiency is closely related to ethnicity/race: 31% of Non-Hispanic blacks were vitamin D deficient; 12% of Mexican-Americans, and 3% of white Americans
- Folate deficiency decreased to less than 1% after foods began being fortified with folic acid in 1998. Blood folate levels in all race/ethnic groups were 50% higher since fortification.
- Young women ages 20 to 39 had the lowest levels of iodine among any age group of women, with iodine levels close to levels indicating iodine insufficiency.
Source: Centers for Disease Control and Prevention. "Second National Report on Biochemical Indicators of Diet and Nutrition in the U.S. Population 2012." March 2012.
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