Use the verb decelerate when you want to slow down, like when you realize you are missing important moments in life by racing around, trying to do everything yourself. If you make an effort to decelerate, you might be happier — and healthier.
Decelerate is the opposite of accelerate, which means "to go faster." Decelerate often describes slowing a vehicle, but it can relate to nearly anything, like a friendship that begins with hanging out nearly every day but decelerates when you move to a new town or get busy with school and sports. It doesn't mean the friendship is ending or over, just that the pace is now a little slower.