Does physical activity reduce cancer risk and does the benefit plateau after a certain level?

The recommended amount of physical activity is typically 150 minutes of moderate exercise per week, so twice that would be around 300 minutes. The evidence we’ve reviewed indicates that moving beyond this higher level doesn’t seem to add further reduction in cancer risk, though it also doesn’t suggest harm. We don’t know if this pattern holds across all types of cancer, or for all people, because only one assertion was available for analysis.

It’s important to note that this doesn’t mean more activity is useless—just that, based on what we’ve seen so far, the protective effect may level off after reaching about double the standard guideline. We also can’t say whether this applies to people with different body types, ages, or health conditions, since the evidence doesn’t specify.

For now, the pattern we’ve observed points toward a possible sweet spot: getting at least the recommended amount of activity, and possibly going up to twice that, may be where the most benefit is seen. Going beyond that doesn’t appear to offer more, but we don’t have enough data to say whether it’s harmful or just neutral.

If you’re active now, staying within or slightly above the recommended levels may be a practical goal. If you’re not active yet, starting with even small amounts of movement could be meaningful.