The Diary Of A CEO with Steven Bartlett
The answer lives in this podcast The Diary Of A CEO with Steven Bartlett · Steven Bartlett

Published August 14, 2026 · Editorial summary by Listenly based on the real audio episode · Topics: myokines · natural killer cells · aerobic training · SPRINT trial

How much exercise does it take to reduce cancer risk through myokine release?

Just 30 minutes a day of aerobic physical activity is enough to downregulate 13 types of cancer. The most prominently affected are breast cancer, colon cancer, and prostate cancer. The primary mechanism is a robust release of natural killer cells into the bloodstream, which travel directly to tumour sites and destroy tumour cells.

What are natural killer cells? Natural killer cells are a type of immune cell that the body deploys as a first-line defence against abnormal cells, including tumour cells. During aerobic exercise, a surge of these cells enters the bloodstream — effectively giving the immune system a targeted, cancer-fighting patrol that wouldn't be activated at the same level at rest.

Exercise doesn't work through a single pathway. Beyond the natural killer cell mobilisation triggered by aerobic activity, both resistance training and aerobic training generate meaningful anti-inflammatory effects — and inflammation is one of the central drivers of tumour growth. The two training modalities therefore compound each other's anti-cancer benefits, making a combined approach more protective than either alone.

This episode of The Diary Of A CEO with Steven Bartlett places the exercise-cancer connection alongside a broader conversation about how physical activity protects multiple organ systems simultaneously — the brain, the cardiovascular system, and the body's defences against cancer all respond to the same 30-minute daily investment.

"Having strong legs is by far the most important tool in your toolbox for the prevention of Alzheimer's disease."

— The Diary Of A CEO with Steven Bartlett

See also

What are myokines and how do they protect the brain during resistance training?

Myokines are signaling molecules released from muscles during resistance training that cross the blood-brain barrier and benefit the brain. Key myokines play a central role in neuroprotection and cognitive resilience.

Why are strong legs particularly important for Alzheimer's prevention?

A study on identical twins with the exact same genetic profile, tracked over a 10-year period with cognitive tests and MRIs, found that the twin with stronger legs showed significantly better cognitive outcomes over time.

What is the ApoE4 gene and how much does it increase the risk of Alzheimer's disease?

The ApoE4 gene (Apolipoprotein E gene) is one of the strongest genetic risk factors for Alzheimer's disease. One copy raises risk by two to three times for males and up to six-fold for females; two copies raise it tenfold for males and fifteenfold for females.

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