Anita Arnold, MD: Dr. Arnold has been in practice for over 30 years as an internal medicine specialist. She practiced in Oxford, MS before joining UTHSC and later West Cancer Center, where she served a combined 16 years. Her work with Threlkeld Infectious Disease further expanded her mastery of diagnosis, testing, and complex clinical management.
As Lifesigns’ Medical Director, Dr. Arnold brings her deep clinical expertise and passion for preventive health to guide the program’s vision and ensure exceptional patient experiences. Her dedication to patient care and prevention is evident in the collaborative, compassionate approach she brings to both patients and fellow providers.
Dr. Leah Tonkin, MD, MBA, DipABLM, is board certified in both Obstetrics & Gynecology and Lifestyle Medicine, bringing over 16 years of private practice experience in Memphis, Tennessee. On March 4, 2024, Dr. Tonkin joined Lifesigns—The Wellness Division of West Cancer Center— and was appointed Executive Director in 2025.
Prior to her current role, Dr. Tonkin served as a hospitalist with Integrated Physician Services, providing emergent care in labor and delivery as well as gynecologic surgery. She was also a partner in a private OBGYN practice. Dr. Tonkin earned her medical degree and completed her internship and residency in Obstetrics & Gynecology at the University of Tennessee Health Science Center.
A dedicated fitness enthusiast and advocate for holistic health, Dr. Tonkin became board certified in Lifestyle Medicine to guide patients through the six pillars of health: Nutrition, Physical Activity, Stress Management, Restorative Sleep, Social Connection, and Avoidance of Risky Substances.
Dr. Felix Caldwell: Dr. Caldwell is a native Memphian and graduated Cum Laude from Vanderbilt University. He received his medical degree from The University of Tennessee Health Science, Chattanooga. Dr. Caldwell is Board Certified in Internal Medicine and is a fellow in the American College of Physicians. Following medical school, he served as Lt. Commander in the United States Naval Reserve with an Honorable Discharge. He enjoys gardening, hiking, going to movies, taking care of his three dogs and aquarium. Dr. Caldwell has practiced medicine for almost 40 years and has worked for Lifesigns since 2006.
Margaret Mitchell, DNP, FNP-C: A native Memphian, Maggie graduated Summa Cum Laude from the University of Memphis and earned her Doctorate of Nursing Practice from the University of Tennessee Health Science Center. As a nurse, she worked in primary care with Le Bonheur Pediatrics and following her NP program, she worked in Nashville as a Family Nurse Practitioner. Maggie has served as a Tennessee Promise Mentor and is on the UTHSC Honor Council; she has participated in the Nursing in Diverse Cultures program in Ecuador and is a member of Sigma Theta Tau Honor Society of Nursing. She lives in east Memphis with her husband, David, their daughter, Elizabeth, and two pups, Ruthie, and Gus.