Hi, My Mother Who Is 76 Has A Pacemaker Almost

Hi, My mother who is 76 has a pacemaker almost 3 years now.
It has been working well for her. She enjoys gardening and staying very active.
A year ago the check-up showed her pacemaker is on demand 86 percent of the time.
Just recently she had her annual check again and it has crept up to 91 percent usage!
She feels well but does need to rest after strenuous activity. Should I encourage her to cut back on some activity? Will the pacemaker have a longer life if she is more sedentary? -Concerned