(Reuters Health) – The better a man’s cardiorespiratory condition, the lower the risk of dying from cancer, suggests a long-term study in Denmark.
Cardiopulmonary fitness is a measure of how well the body uses oxygen during strenuous exercise. Good cardiorespiratory fitness is well known to be associated with better cardiovascular health, but less is known about its effect on cancer risk, the study team writes in the British Journal of Sports Medicine.
“We understand that many cancers are due to unhealthy lifestyle factors and therefore many cancers are preventable,” lead author Dr Magnus Thorsten Jensen told Reuters Health by email.
âIt has already been reported that higher levels of physical activity can reduce the risk of cancer, which is one of the reasons why physical activity is encouraged by the World Health Organization,â said Jensen, researcher at Holbaeck Hospital in Denmark.
Jensen and his colleagues analyzed data from the Copenhagen Male Study, which recruited middle-aged men who worked in Copenhagen from 1970.
The researchers followed 5,131 men aged around 49 on average who were cancer-free at the start of the study. All participants underwent VO2 Max testing as well as regular physical exams at that time.
VO2 Max measures the maximum amount of oxygen the body can process for energy during exercise and is measured in milliliters of oxygen per kilogram of body weight per minute (mL / kg / min).
Over the next 44 years, 4,482 participants died, including 1,527 from cancer.
The researchers found that for every 10 ml / kg / min increase in VO2Max during the baseline test, there was a 17% lower risk of cancer death and an 11% lower risk of cancer death during baseline testing. the follow-up period.
âOur results show that the fitter you are, the longer you live and the lower your risk of dying from cancer,â Jensen said.
However, this correlation was not observed between self-reported physical activity and the risk of dying from cancer.
âWe find that it’s not enough to be physically active, you have to really be in good shape,â Jensen said. “Very often, of course, physical activity and fitness go hand in hand, but our study shows that the most important factor is your actual level of fitness.”
When researchers looked at specific types of cancer, the reduction in risk with better cardiorespiratory capacity was maintained, with the exception of prostate cancer, where no difference was seen.
Despite its large size and long follow-up, the study is limited by the fact that undetected cancers or other diseases could be the cause of the poor physical condition of some men, the researchers admit.
Having such a long follow-up time allowed the study to exclude from the analysis men who died within the first 20 years of the study, Jensen noted. âIt didn’t change the results, so underlying cancer is a very unlikely explanation for our results,â he said.
âI find our results very optimistic and encouraging,â he said. âGood general fitness can be achieved by anyone and does not necessarily require expensive equipment or major investments. “
There are several biological reasons why a person in better physical shape would be less likely to develop cancer, said Dr. Kim Dittus, an oncologist at the University of Vermont College of Medicine in Burlington.
âSomeone who is fitter is likely to be at a normal weight because exercise can help control weight,â said Dittus, who was not in the study.
Overweight and obese men and women are likely to have higher estrogen levels, she said. Being overweight also influences insulin and insulin resistance. These hormonal differences have been linked to an increased risk of different types of cancer.
Exercise is also important for people who have been diagnosed with cancer, Dittus added.
“We have a number of epidemiological studies suggesting that people who are more physically active are less likely to have their cancer recurring, so they have better cancer outcomes than those who are inactive,” he said. she declared.
Dittus added that people with better cardiorespiratory condition may also tolerate chemotherapy better.
SOURCE: bit.ly/2ga6jAJ British Journal of Sports Medicine, online November 25, 2016.