Cleanliness, comfort, climate
FITT principle: Frequency, Intensity, Time, and Type.
They can increase their exercise from 3 days per week to 5 days per week. They can aim for a further distance during their exercise. They can increase the daily time from 20 minutes into 40 minutes. They can change the exercise from jogging to running.
Don't really worry about pushing too hard, it's even ok if you were to break a rib or two. it's better to push too hard than not hard enough
