Exercise in Adolescence May Reduce Adult Cancer Risk

Story at-a-glance -

  • Women with a history of exercising 1.3 hours per week during their teen years had a 16 percent lower risk of dying from cancer, and a 15 percent lower all-cause mortality risk
  • Earlier research found that strenuous activity at age 12 was associated with a reduced risk for breast cancer during pre- and post-menopause
  • Exercise is also potent preventive medicine in the fight against dementia. People who had greater cardiorespiratory fitness in their teens and 20’s scored better on cognitive tests in their mid-40’s and 50’s

By Dr. Mercola

While focusing on the immediate benefits of exercise is typically more motivating than the potential long-term benefits, there’s no doubt that staying active throughout life can pay dividends far into the future.

As a general rule, the earlier you start and the longer you stay active, the greater the payoffs in terms of health, disease prevention, and longevity. Recent research1,2 highlights the importance of staying active during your teenage years.

As reported by Reuters:3

“Researchers who analyzed how often women exercised while in their teens found that being active for just 1.3 hours a week had a positive impact as they got older.

‘The main finding is that exercise during adolescence is associated with a reduced risk of mortality, or death, in middle aged to older women’...”

Active Girls Live Longer

Overall, women who had a history of exercising for an average of 1.33 hours per week during their teen years had a 16 percent lower risk of dying from cancer, and a 15 percent lower all-cause mortality risk.

Those who were active as teens and kept up their exercise habit as adults had a 20 percent lower risk of death from all causes.

According to lead author Sarah J. Nechuta, Our results support the importance of promoting exercise participation in adolescence, and highlight the critical need for the initiation of disease prevention early in life."

An earlier study4 found very similar results. Here, strenuous activity at age 12 was associated with a reduced risk for breast cancer during pre- and post-menopause.

Women who had engaged in moderate exercise during adulthood also had a significantly reduced risk of post-menopausal tumors.

Exercise Reduces Risk of Many Cancers in Both Men and Women

This certainly isn’t the first time researchers have found links between exercise and reductions in cancer and early death.

According to a 2003 paper5 published in the journal Medicine & Science in Sports & Exercise, "more than a hundred epidemiologic studies on the role of physical activity and cancer prevention have been published."

The authors noted that:

"The data are clear in showing that physically active men and women have about a 30 to 40 percent reduction in the risk of developing colon cancer, compared with inactive persons…

With regard to breast cancer, there is reasonably clear evidence that physically active women have about a 20 to 30 percent reduction in risk, compared with inactive women.

It also appears that 30 to 60 min·d-1 of moderate- to vigorous-intensity physical activity is needed to decrease the risk of breast cancer, and that there is likely a dose-response relation."

An oft-repeated pattern is that the longer you exercise, the more pronounced the benefits. The featured study looked at exercise patterns during women’s teen years.

Another recent study6,7 found that men who stayed fit in middle age had a 55 percent lower risk of lung cancer and a 44 percent lower risk of bowel cancer after the age of 65.

The Importance of Exercise During and After Cancer

Should you end up with a cancer diagnosis, exercise may significantly boost your chances of recovery and survival. It also helps diminish your chances of recurrence. Studies demonstrating these benefits include the following:

  • Improved survival: A 2005 Harvard study8 found that breast cancer patients who exercised moderately for three to five hours a week cut their odds of dying from cancer by about half, compared to sedentary patients.
  • In fact, any amount of weekly exercise increased a patient's odds of surviving breast cancer to some degree. This benefit remained constant regardless of whether women were diagnosed early on or after their cancer had spread.

  • Reduced recurrence: A study published in 2012 found that breast and colon cancer patients who exercised regularly had half the recurrence rate compared to non-exercisers.9

Improving your chances of recovery and cutting your risk of recurrence by 50 percent is quite significant, wouldn’t you agree? You’d certainly be hard-pressed to find any pill improving your odds of surviving cancer by that much. The British organization Macmillan Cancer Support encourages all cancer patients to engage in moderate-intensity exercise for two and a half hours per week, stating that the advice to rest and take it easy after cancer treatment is a really outdated view.

Johns Hopkins in the US also recommends exercise during and after cancer treatment,10 as discussed in the video above. When done during cancer treatment, exercise has been found to mitigate a number of common side effects of chemotherapy drugs and radiation, including:

Reducing fatigue and improving your energy levels Managing stress, anxiety, low mood, or depression Improving bone health
Improving heart health (some chemotherapy drugs and radiotherapy can cause heart problems later in life) Building muscle strength, relieving pain, and improving range of movement Maintaining a healthy weight
Sleeping better Improving your appetite Preventing constipation

How Does Exercise Lower Cancer Risk?

So, just HOW does exercise help you fight cancer? One of the most potent anti-cancer mechanisms of exercise is its ability to decrease insulin resistance. This is a profoundly effective strategy to reduce your cancer risk, as it creates a low sugar environment that discourages the growth and spread of cancer cells.

Sugar’s ability to promote cancer has been known since the early 1930s, following Otto Warburg’s discovery that malignant tumors exhibit an increase in anaerobic glycolysis — a process whereby glucose is used as a fuel by cancer cells with lactic acid as an anaerobic byproduct. In short, he discovered that sugar feeds cancer, and he received the Nobel Prize in medicine for this discovery in 1931.

Since then, the evidence for the link between sugar and cancer has only gotten stronger, and research now suggests a ketogenic diet may be a potent strategy in the treatment of many cancers. The reason for this is because while all normal cells in your body can use either glucose or ketone bodies from fat as fuel, cancerous cells lack this metabolic flexibility.

They can only survive on glucose. So a ketogenic diet, which severely restricts sugar and his high in healthy fats, effectively “starve” the cancer cells out. Exercise, by lowering your blood sugar levels and normalizing your insulin sensitivity, has a similar effect — it essentially creates an environment that is less conducive to cancer growth.

Exercise also improves blood circulation, driving more oxygen into your tissues and circulating immune cells in your blood. By improving blood flow to your liver, it also helps your body detoxify potentially harmful substances, including excess estrogen that may spur estrogen-sensitive cancers. Animal research,11,12 also suggests exercise helps reduce your chances of developing liver cancer, which is among the most common types of cancer.

Exercising in Your Teens and 20s Boosts Mental Sharpness in Middle-Age

Besides reducing your cancer risk, exercise is also potent preventive medicine in the fight against dementia, which typically takes decades to develop. Here too we see that fitness early on in life tends to set the groundwork for healthier brain aging. For example, after examining data collected over a 25-year period from 2,700 American men and women, researchers found that those who had greater cardiorespiratory fitness in their teens and 20s scored better on cognitive tests in their mid-40s and 50s.13,14,15

Those who were fitter in their early adulthood also scored better on tests designed to assess reaction speed and the mental agility needed to answer trick questions. Here, the impact of fitness was deemed to be independent of other dementia-related risk factors such as diabetes, high cholesterol, and smoking.

Physical exercise has also been found to protect against other age-related brain changes. For example, those who exercise the most tend to have the least amount of brain shrinkage over time. Not only that, but exercise actually causes your brain to grow in size. In one study, seniors who walked 30 to 45 minutes, three days per week for one year, showed a two percent increase in the volume of their hippocampus16 — a brain region associated with memory.

Family Workouts Have Immediate and Long-Term Benefits

Parents can do a lot to encourage their kids to make fitness into a lifelong habit, and setting a good example may be one of the most powerful motivators. Many parents end up dropping their exercise routine once their little ones are born, but with a little planning and a few modifications you could easily turn your single workout into a family affair. As noted by Dana Santas, creator of Radius Yoga Conditioning, in a recent CNN article:17

“Declining opportunities for family interaction and increasing sedentary time at home represent a significant threat to our children's health and wellness... Designating time for quick, fun family workouts is an efficient way to foster bonds and boost activity levels simultaneously.

My husband and I have been working out with our children every Sunday for years... You don't need a trainer or a gym. If you have a driveway or sidewalk, or access to a small playground or park, you have enough space. And creating a simple, effective workout doesn't require a personal training certification.”

Dana goes on to describe a sample workout routine that the whole family can do together. After a few quick warm-up movements, she suggests incorporating some agility drills, which can be as simple as hopping and skipping exercises, followed by sets of pushing, pulling, hinging, and squatting movements, finished off with some cool-down stretches. 

Exercise for Health and Longevity

There’s no denying that exercise can have a profound impact on your health, and a major part of its benefit lies in its ability to prevent disease — in large part by improving your insulin and leptin sensitivity, which is a hallmark of most chronic health problems. Dementia and cancer are but two in an inordinately long list of health problems that can arise as a result of chronic inactivity.

Ideally, you’ll want to establish a comprehensive exercise program that includes high-intensity exercises and strength training — both of which have been shown to be of particular benefit for brain health and cancer prevention. Naturally, if you have cancer or any other chronic disease, you will need to tailor your exercise routine to your individual circumstances, taking into account your fitness level and current health.

I also urge you to consider walking more, in addition to your regular workout regimen. Ideally, aim for 7,000 to 10,000 steps per day. Don’t guess here. Get an authentic device that will accurately and objectively record your steps. Also avoid sitting as much as possible — ideally limiting your sitting to three hours a day or less.

Remember, it’s never too late to start exercising, but ideally, if you have children, it would be wise to help them build a solid foundation for good health by encouraging daily physical activity. In many cases, that means devising ways to lure them away from electronic games and gadgets. One great way to do that is to exercise as a family, with focus on having fun together. Not only will everyone benefit from the physical activity, but it’ll help strengthen emotional bonds as well, which can go a long way toward warding off teenage angst and other emotional difficulties that may arise.