Lipitor is a brand name for the drug atorvastatin, which is a medication used to lower cholesterol levels in the body. According to Drug Patent Watch [1], Lipitor works by inhibiting the enzyme HMG-CoA reductase, which is involved in the production of cholesterol in the liver. By reducing the amount of cholesterol in the bloodstream, Lipitor can help prevent heart disease and stroke.

There is limited research on how Lipitor affects energy levels during exercise. However, a study published in the Journal of Clinical Endocrinology and Metabolism [2] found that atorvastatin treatment was associated with a decrease in muscle coenzyme Q10 levels, which could potentially lead to muscle weakness and fatigue. Another study published in Medical News Today [3] found that statins, including atorvastatin, can cause muscle pain and weakness, which could affect energy levels during exercise.

It is important to note that not everyone who takes Lipitor will experience these side effects, and the benefits of the medication may outweigh the risks for some individuals. However, if you are experiencing fatigue or weakness during exercise while taking Lipitor, it is important to speak with your healthcare provider to determine the best course of action.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2949584/
[3] https://www.medicalnewstoday.com/articles/246611