Exercising a “disgustingly small” amount per day can lower the risk of cancer, according to a fitness expert.

Nutritional scientist and professional bodybuilder Dr. Layne Norton claimed that “four minutes of vigorous activity a day” will greatly reduce an individual’s cancer risk.

“Exercise is one of the only things that you can do, independent of weight loss, that will improve all your health parameters,” Norton told host Dr. Rhonda Patrick on the FoundMyFitness podcast last week.

Citing a study published last year in JAMA Oncology, Norton said that researchers found that “vigorous physical activity” done “cumulative” throughout the day can lower the risk of cancer by 20%.

“I got in trouble because I called it a disgustingly small amount, but it really is,” the fitness expert shared.

He went on to reveal that the study found that exercising for “10 minutes” daily dropped the risk of cancer by 30%.

The study also found that just three short bursts of exercise per day can lead to a 40% reduced risk of cancer and cancer death and a 50% reduction in heart disease death. 

“If you just go walk vigorously for 30 minutes in a day you’re killing it,” the nutritional scientist said.

While some may question the findings because it was a “cohort study,” Norton quickly pointed out that “randomized control trials” have found similar indications to exercise and cancer risk.

“We have randomized control trials looking at very short bursts of exercise, seeing improvements in glucose metabolism, blood lipids, inflammation, and then now the cognitive stuff too,” Norton shared.

The fitness guru also shared that short periods of exercise have been shown to improve mental health.

He explained that the “randomized control trial” found that men with “major depressive disorder or general anxiety disorder” who did two 25-minute sessions of resistance training a week for eight weeks saw “significantly improved symptoms.”

“The effect size for major depressive disorder was 1.7,” Norton said, citing a study released last year in Psychiatry Research.

“For those who aren’t familiar with effect sizes, .2 is a small effect size, 0.5 is modest, and 0.8. Anything above 0.8 is considered large, 1.7 is massive,” Norton said.

Selective serotonin reuptake inhibitors (SSRI) — a class of drugs that are commonly prescribed to treat depression — usually fall between 0.3 to 0.8, and “the best you see is about 0.8,” he shared.

The professional bodybuilder clarified he wasn’t suggesting people should stop taking their SSRIs instead of working out but to consider other additional options to add to treatment — like exercising.

“I’m not saying we should get rid of SSRIs and have everybody exercise because sometimes maybe someone needs an SSRI just to get out of bed and actually go exercise,” Norton said. “But if we’re looking at how powerful that lever is, that’s amazing.”

However, nutritional scientists understand that getting started with routine exercise can be challenging and suggest that listeners consider it like “brushing your teeth.”

“Do you feel motivated to brush your teeth? No, you do it because you know if you don’t brush your teeth, they’re going to go to crap,” Norton said. “The same thing happens with your body if you don’t exercise.”

According to Johns Hopkins cardiologist Dr. Seth Martin, the average resting heart rate is between 60 and 100 beats per minute (BPM).

The “sweet spot” for exercise depends on a person’s age, and the target heart rate is “usually between 50 percent and 85 percent” of their maximum safe heart rate.

For a 50-year-old, it’s crucial to calculate the maximum heart rate, which can be obtained by subtracting the age from 220. In this case, it’s 170 BPM, Martin shared.

If someone aims for a 50% exertion level, their target should be 50% of that maximum, 85 BPM.

However, if a person wants to push themself to 85% of the maximum, their target should be 145 BPM.

The target heart rate that a 50-year-old should aim for during exercise is 85 to 145 BPM.

Martin noted that it’s important not to “get overly fixated on numbers” and instead just strive to exercise regularly.