Dutch healthy exercise norm: NNGB (Nederlandse Norm Gezond Bewegen)
For children younger than 18 years: at least one hour of moderately intensive physical activity (5 MET (e.g. aerobics or skateboarding) to 8 MET (e.g. running 8 km/h)) every day (summer and winter), where at least twice a week the activity is aimed at improving or maintaining physical fitness (power, agility and coordination).
For adults (18 to 54 years) the norm is: at least half an hour of moderately intensive physical activity (4 to 6.5 MET; walking (5km/h) or cycling (16 km/h) briskly), on at least five days a week (summer and winter).
For over-55s the norm is: at least half an hour of moderately intensive physical activity (3 to 5 MET; walking (4km/h) or cycling (10 km/h)) on at least five days a week, but preferably every day (summer and winter). For non-active people, with or without physical limitations, all extra physical exercise is significant, regardless of intensity, duration, frequency and type.
A MET (metabolic equivalent) value expresses the intensity of a physical activity. MET values are used to divide activities into three categories: light, moderate and heavy. In the Netherlands the MET threshold values are specified taking age into account.