Reference summary — not medical advice or a personal risk estimate.
Physical inactivity
Quick answer
Not IARC-classified — this is not a chemical or physical agent IARC rates. Recognized as a cancer risk factor based on observational evidence. Lifestyle. Not meeting WHO's minimum recommended physical activity (150 minutes of moderate-intensity per week for adults).
Summary
Lack of regular physical activity is associated with increased risk of colon, breast, and endometrial cancers.
Detail
WHO and WCRF/AICR identify physical inactivity as a modifiable cancer risk factor, with strongest evidence for colon, postmenopausal breast and endometrial cancer. The proposed mechanisms include effects on body weight, hormone levels, insulin sensitivity and immune function. WHO physical-activity guidelines recommend at least 150 minutes of moderate-intensity activity per week for adults.
What's not established
This classification is based on observational or associative evidence. It does not establish that this factor directly causes cancer as opposed to correlating with other risk factors, a safe exposure threshold, or your personal risk.
Regional relevance
global
Documented in these products
Presence in a product category doesn't imply the product causes cancer. Click each to see the source and context.
Evidence sources
Every claim on this page traces back to one of these. Click through to read the primary document yourself.
Primary sources
WHO
WHO — Cancer fact sheet
NCI
NCI — Risk Factors: Obesity
Supporting sources
Canadian Cancer Society
Canadian Cancer Society — Reduce your risk
Cancer Research UK
Cancer Research UK — Causes of cancer and reducing your risk
IARC / WHO — European Code Against Cancer
European Code Against Cancer (5th edition) — 14 ways you can help prevent cancer
Cancer Council Australia
Cancer Council Australia — Causes of cancer
WCRF/AICR
WCRF/AICR — Diet, Nutrition, Physical Activity and Cancer: a Global Perspective (Third Expert Report)
WCRF/AICR
WCRF — Cancer Prevention Recommendations
Last reviewed: October 2026
Official reference list
A government list some readers use alongside the primary evidence. Meyron is not affiliated with it. A chemical being listed does not by itself describe a risk from any particular product.
- California Prop 65 list
State of California's list of chemicals known to cause cancer or reproductive harm.