The design of our cities and urban transportation systems is a crucial factor in boosting physical activity in the population:

• Active transport —getting around on foot or by bicycle— on a daily basis is the most practical and sustainable way to increase physical activity.
• A good public transport network makes it easier for people to walk more and reduces private vehicle use.
• Green spaces are an important factor and provide a safe environment for physical activity.

All these measures are included in this study published in The Lancet, , which analysed physical activity in 14 cities.