We get it: absolutely no one wants cancer, or even gets it think About having cancer. The good news is that, thanks to research and modern medicine, we’ve come a long way in the treatment and prognosis of many cancers, especially when doctors catch them early. However, although we know a lot about this disease, there is still a lot we don’t know.
“We are still trying to identify risk factors for many cancers,” said Dr. David Yashar, MDis a hematologist and medical oncologist at Memorial Care Todd Cancer Institute at Long Beach Medical Center. “However, we know there are some clear risk factors, such as genetics, certain environmental factors and certain types of lifestyle factors.”
You can’t change your genes, but oncologists say you can adjust your habits to lower your risk of cancer. In fact, research, including 2020 molecular oncology Reviews suggest that 30 to 40 percent of cancers can be prevented through lifestyle changes. However, we often take an “all or nothing” approach to our habits: we either follow the Mediterranean diet 100% or not at all. We are either couch potatoes or marathon runners. Oncologists advocate a gentler mindset.
“Small, sustained changes in modifiable behaviors can meaningfully reduce cancer risk across a lifetime,” shares Dr. Shikha Jain, MD, FACPis a triple board certified hematologist and oncologist and an associate professor at the University of Illinois Cancer Center. “Knowing what is within your control promotes prevention rather than fear and allows people to focus their efforts where they can really make a difference.”
Oncologists recommend focusing on breaking this popular habit, which increases cancer risk than most people realize, and sharing what to do instead.
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Oncologists say this popular habit poses higher cancer risk than people realize
Oncologists warn that physical inactivity increases the risk of cancer. However, too many people don’t think of exercise as a tool to protect themselves from cancer.
“A sedentary lifestyle can lead to a person being overweight or obese,” Dr. Yashar said. “We know that increased fat content causes inflammation, which is a known risk factor for cancer.”
He also said research shows a link between colorectal cancer and obesity.
Tatyana Metleva/Getty Images (Tatiana Metleva/Getty Images)
That said, size doesn’t tell the whole story. Even if you don’t gain weight or become obese, Dr. Jain says you will experience many changes, including:
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Decreased muscle glucose uptake
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increased insulin resistance
Dr. Yashar added that a sedentary lifestyle triggers increased secretion of sex hormones, which increases the risk of hormone-sensitive cancers such as breast cancer.
What happens when you exercise
On the other hand, Dr. Jain points out that physical activity:
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Lower insulin and inflammatory markers
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Improve immune surveillance
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Helps regulate hormones like estrogen and testosterone
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Supports healthy body composition
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Improve intestinal motility and microbiome health
“Together, these changes create a biological environment that is not conducive to cancer development and progression,” she explains.
In fact, a 2025 study in the British Journal of Sports Medicine showed that people who replaced daily sitting with light/moderate to vigorous physical activity reduced their chances of developing cancer by 26%. The Centers for Disease Control and Prevention says physical activity can reduce your risk of: At least 8 different cancer typessinclude:
RELATED: Oncologists plead with people to limit popular cooking methods
How much exercise do you need to reduce your cancer risk?
Oncologists we interviewed noted that the American Cancer Society guidance documents five
Several hours of moderate-intensity physical activity each week may reduce cancer risk. sounds like a a lot ofbut you don’t have to do it all in one day.
“This equates to 45 minutes of moderate-intensity activity per day,” says Dr. Yashar. “Moderate-intensity activities include brisk walking, leisurely biking, ice skating, or rollerblading.”
Honestly, these sound like a lot of fun, and you’ll find that they don’t require an all-out sprint. In fact, 2025 British Journal of Sports Medicine Studies have found that higher step count, but not pace/intensity, is associated with lower cancer risk.
That said, it’s best not to record recommended physical activity and then sit for the rest of the week.
“New data suggest that even for people who meet exercise guidelines, sitting for long periods of time may increase the risk of cancer, similar to what we see with cardiovascular disease,” reports Dr. Jain.
Got a desk job? Don’t give it up! Instead, spend small amounts of time exercising. She suggests:
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Stand or move for a few minutes every 30-60 minutes
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Attend a walking meeting or make a phone call
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Use sit-stand desks whenever possible
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Add exercise “snacks” into your day
This is an investment in your health. “Exercise is protective, but it doesn’t completely eliminate the dangers of sitting all day,” Dr. Jain reminds us.
Next:
RELATED: Brain health experts implore you to stop your breakfast-only habit
Source:
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Dr. David Yashar, MD, hematologist and medical oncologist at MemorialCare Todd Cancer Institute at Long Beach Medical Center
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Dr. Shikha Jain, MD, FACP, is a triple board certified hematologist and oncologist and associate professor at the University of Illinois Cancer Center
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Physical activity, obesity, and sedentary behavior in cancer etiology: epidemiological evidence and biological mechanisms. molecular oncology.
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Is the link between overweight and obesity and colorectal cancer underestimated? A comprehensive review of systematic reviews and meta-analyses. European Journal of Epidemiology.
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Physical activity and cancer. CDC.
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American Cancer Society Diet and Physical Activity Guidelines for Cancer Prevention. American Cancer Society.
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Number and intensity of total daily physical activity, step count, and cancer risk in the UK Biobank. British Journal of Sports Medicine.
This article was originally published by Parade on February 19, 2026 and first appeared in the Health & Wellness section. Click here to add Parade as a preferred source.