It's hailed as the "wonder drug" of 2017 that all doctors should prescribe - and it's free.
Exercise is hard to beat for its power to not just prevent but also treat illness.
It is possible to walk your way to better health, according a group of experts on the physical activity policy group of the Royal College of Physicians.
Co-chair of the group, Professor Sean Gaine, a specialist in the Mater Hospital, Dublin, said they were urging fellow doctors to "engage with patients to increase their levels of physical activity, through advice, prescription and referral".
The impressive long-term benefits include:
- A 30pc risk reduction in deaths from any cause;
- Reduced chance of heart disease, stroke and cardiovascular disease, type 2 diabetes, breast and colon cancer;
- 29pc-30pc less risk of depression;
- 30pc lower risk of falls in elderly;
- 36pc-68pc reduced risk of hip fracture.