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Meet the Team

Dedicated, compassionate, and prepared.

It is quick and easy to schedule your appointment online, just click the “SCHEDULE NOW” button in the menu above, or select your preferred medical provider by using the buttons below.

You can also reach us by phone at (303) 730-2167.

Medical Team

Dr. Ashleigh Sartor (Duncan), MD

Lead Physician | Primary Care | Functional Medicine | Weight Loss

Dr. Ashleigh Sartor, MD  Schedule with Dr. Sartor

Dr. Ashleigh Sartor, MD is a graduate of Swedish Medical Center Family Medicine Residency. Prior to moving to Denver for residency, she received her medical degree from Wayne State University in Detroit, and undergraduate degrees in Chemistry and Biology from Hope College in Michigan.Dr. Sartor enjoys the opportunity that Family Medicine provides for forming therapeutic relationships with a large variety of patients. Dr. Sartor brings a broad scope of care to Altitude Internal Medicine and active in all aspects of medicine including Women’s Health.

Dr. Sartor maintains certification in both Primary Care and Functional Medicine.  Functional Medicine uses a “whole person” approach to address the underlying causes of disease, engaging both patient and practitioner in a therapeutic partnership.  She embraces healthy living and healthy cooking and brings this expertise to her patients and as the director of the ‘Elite Medical Weight Loss’ program at Altitude.

Dr. Rebecca Nickell, DO  Schedule with Dr. Nickell

Dr. Rebecca Nickell is an Osteopathic Physician who graduated from Oklahoma State University College of Osteopathic Medicine in 2002.  She learned to love Colorado while completing her residency at Southern Colorado Family Medicine in Pueblo, Colorado.  She enjoys treating the whole person, using a whole body rather than a disease focused approach to health and wellness.  Her interests include general family medicine, well women care, osteopathic manipulation, mental health, and assisting with weight loss.  She loves taking care of whole families from young children to their grandparents.

Dr Nickell grew up all over the South.  After hearing about how her grandfather, a small-town family practice physician, really took care of his whole community, she knew it was her dream as well.  When not practicing medicine, she loves spending time with her three daughters and extended family.  She loves reading, live theater, sewing, and designing costumes for the whole family.

Dr. Rebecca Nickell, DO

Primary Care | Family Medicine | Osteopathic Manipulation

Summer Irelan, PA-C

Primary Care | Family Medicine

Summer Irelan, PA-C  Schedule with Summer

Summer attended and graduated from Regis University with Dean’s List honors, with a Bachelor of Science in Biology. She then worked for a few years as a Chemist in a pharmaceutical company before going back to school for her Physician Assistant Certificate and master’s degree in medical science at Red Rocks and Saint Francis University, respectively. She feels that fostering relationships with her patients and educating them on disease processes and sequela are key to improving the health of her patients. Engaging her patients and making a collaborative plan of care with shared and informed decision making achieves the best outcomes for the patient. Her philosophy on practicing medicine is to treat the whole patient and that they are in control of their health, and she is just here for advice.

Personally, she enjoys spending time in the mountains hiking, alpine climbing, camping, rafting, and snowboarding. She has made over 70 mountain summits including Mount Kilimanjaro and Aconcagua. She enjoys travel medicine and high-altitude medicine consults. She believes that daily exercise and a healthy diet are imperative to longevity. She also took care of her father for over a year before he passed, when he had end stage diabetes and dementia, so she understands the stresses that come with care taking for a loved one despite how priceless it is to do so.

Clay Whiddon, PA-C  Schedule with Clay

Clay is a Colorado native that received a bachelors of Science degree in Human Biology from University of Colorado at Colorado springs. He went on to receive at Master’s Degree in Public Health from Westminster College in Salt Lake City leading to a direct commission onto active duty as a Public Health Officer in the Air Force. After 4 years and multiple decorations he transitioned to the National Guard where he continues his service as he completed a Master’s in Physician Assistant Studies from the University of South Dakota. He has worked in the Emergency Department and is excited to move to Primary Care. Clay has worked in all his previous careers to prevent disease in communities and is ecstatic about the opportunity to continue that mission in Primary Care for his patients.

Clay spends his time outside of the clinic with his wife Jenny, their son Parker and daughter Adalyn enjoying life in Colorado. He is an avid cyclist, runner, hiker, hunter, fly-fisherman and skier.

Clay Whiddon, PA-C

Primary Care | Family Medicine

Katie Rodgers, NP

Primary Care | Family Medicine | Adult and Geriatric Medicine

Katie Rodgers, NP  Schedule with Katie

Katie is originally from Vermont and moved to Colorado in 2017 after living in Boston, MA for 6 years. She worked as an Emergency Room RN for 8 years until completing her Masters in Nursing in 2021. Katie is a licensed Adult-Gerontology Primary Care Nurse Practitioner. Her experience as a Nurse Practitioner includes Primary Care, Infusion Medicine and Correctional Medicine.

For fun, Katie likes to see theatre, make candles and garden. She spends her evenings hanging out with her husband and two pups. She enjoys hiking and paddle boarding in the summer and snowboarding in the winter. Her favorite season is Fall, because of all the maple flavored treats!

Katie enjoys working in primary care as it allows for a strong patient relationship and the environment to provide individualized patient care.

Lindsey Andreoli, NP  Schedule with Lindsey

Lindsey is a Nurse Practitioner (NP), board certified in Adult and Geriatric care since 2014.  She completed her undergraduate nursing program at University of Wisconsin-Madison, and later earned her Master of Science in Nursing degree at Rush University in Chicago, IL. Lindsey worked as a Hepatology Nurse Practitioner for 8 years before shifting her focus to Primary Care to better align with her philosophy of health promotion and disease prevention. She enjoys opportunities to form lasting relationships with her patients and encourages them to become their own health advocates.

Lindsey is originally from Wisconsin, and after spending much of her life in the Midwest moved to Colorado in 2017.  Her interests include spending time with her husband, 2 young girls, along with cooking, gardening, hiking and soaking in all that the Colorado outdoors has to offer.

Lindsey Andreoli, NP

Primary Care | Family Medicine | Adult and Geriatric Medicine

Administrative Team

Email Erin  Email Erin

Altitude welcomes Erin Harshell as the practice manager for our SW Littleton office.

Erin Harshell

Practice Manager, Littleton

Executive Team

Shara Hansen, MSN, FNP-C, MBA

Co-founder and Executive Vice Chair | Director, Altitude Health Foundation

Shara Hansen, MSN, FNP-C, MBA

Shara Hansen is a Board Certified Nurse Practitioner who earned her undergraduate degree in Nursing from Bradley University in Peoria, Illinois and her master’s degree as a Family Nurse Practitioner from the University of Colorado. Shara has been practicing primary care medicine for over 20 years.

She has advanced training in Clinical Nutrition, Anti-aging Medicine, Bio-identical Hormone Therapy, Acupuncture, Medical Aesthetics, and in Executive Leadership.  Shara serves as the CEO of Altitude Family & Internal Medicine and is the director of our nonprofit entity, the Altitude Health Foundation.

Shara values quality, patient-centric, holistic care for every patient. She is married to her childhood sweetheart and has 2 beautiful daughters. She enjoys spending time with her family and spending time outdoors hiking, biking, running, swimming, snowshoeing, and snowboarding.

Dr. Doug Hansen, MD, MBA

Dr. Hansen earned his medical degree with honors at the University of Illinois College of Medicine and completed his residency training at St. Anthony Hospital in Denver.  Dr. Hansen is the only triple board-certified Primary Care Physician, Clinical Lipidologist, and Nutrition Specialist in the United States.  Dr. Hansen has been practicing in Denver since 1999 and serves as the Executive Chair for Altitude Family & Internal Medicine, Professor of Medicine at the University of Colorado School of Medicine, and Board Trustee for Colorado Health Neighborhoods.

Dr. Hansen is a nationally-featured expert on heart disease, hypertension, cholesterol, diabetes, nutrition, and longevity.  He has been featured on NBC’s TodayShow.com and MSNBC and has contributed to many books and publications including Breakthroughs in Natural Healing and Building Foundations for Change from the bestselling “Wake Up and Live the Life You Love” Series.  Dr. Hansen’s latest highly anticipated book, Transcending Cholesterol is scheduled for release in the near future.

For his clinical work, Dr. Hansen is proud to be distinguished as a Patients’ Choice Award winner, an honor bestowed to the top 5% of physicians in the United States as voted by patients, for several years.

Doug Hansen, MD, MBA

Founder and Executive Chair

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Keep In Touch

 info@altitudemedicine.com
 (303) 730-2167
 (303) 996-4820