Based on the information available, there is no definitive evidence to suggest that Lipitor's effectiveness changes with exercise. Lipitor, a statin medication, works by reducing the amount of cholesterol your body absorbs and by helping your body get rid of cholesterol [1].

Exercise, on the other hand, can help lower cholesterol levels by helping you lose weight, reducing inflammation, and boosting your body's HDL, or "good," cholesterol [2]. However, these effects are not specific to Lipitor and apply to cholesterol levels in general.

It's important to note that Lipitor and exercise work in different ways to manage cholesterol levels. While Lipitor is a medication that directly affects cholesterol levels, exercise is a lifestyle change that can help manage cholesterol levels [3].

In conclusion, while both Lipitor and exercise can help manage cholesterol levels, there is no evidence to suggest that Lipitor's effectiveness changes with exercise. It's recommended to use both, if prescribed by a healthcare professional, as part of an overall plan to manage cholesterol levels.

Sources:
[1] "What is Lipitor?" Mayo Clinic, Mayo Foundation for Medical Education and Research, 11 Feb. 2021, <https://www.mayoclinic.org/drugs-supplements/lipitor-oral-route/description/drg-20065544>.
[2] "Exercise for Lower Cholesterol." Mayo Clinic, Mayo Foundation for Medical Education and Research, 21 Nov. 2020, <https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/in-depth/lower-cholesterol/art-20045935>.
[3] "Lipitor (Atorvastatin) and Exercise." DrugPatentWatch, <https://www.drugpatentwatch.com/drugs/lipitor>.