Menu Healthy Lifestyle Diseases & Conditions First Aid Symptoms Tests & Procedures Videos Definitions FAQs Blood sugar levels can fluctuate for many reasonsMy blood sugar level is up even though I keep a consistent diet and exercise schedule. What could be the cause?Updated: 2022-06-07Answer SectionMany factors can cause high blood sugar (hyperglycemia) in people with diabetes. Factors include: Food and physical activity choices Dehydration Certain medications, especially those that contain steroids Skipping or not taking enough medication that lowers blood sugar Taking medications incorrectly Illness, infection, injury or surgery Stress (both positive and negative stress) Hormonal changes Physical or emotional stress triggers the release of hormones that can cause high blood sugar levels. Menstrual periods and menopause also cause changes in the hormones that affect blood sugar levels. Regular blood sugar testing can uncover patterns. This can help you and your health care team control your diabetes. If you experience persistent hyperglycemia, talk with your team about adjusting your diabetes treatment. © 1998-2022 Mayo Foundation for Medical Education and Research(MFMER). All rights reserved. Terms of Use