Key points from article :
Research used data from the UK Biobank of 474,919 people across the country.
Data analysed at the National Institute for Health Research, Leicester Biomedical Research Centre.
Average UK life expectancy is 79 for men and around 82 for women.
Underweight people who walk slowly have the lowest life expectancy – 72 for women and 64 for men.
Slow walker people were at higher risk of heart-related disease, regardless of the person's weight.
Encouraging the population to engage in brisk walking may add years to their lives.
