Why Blood Sugar Is Harder to Control During Illness, Injury, or Recovery

“When you’re sick or injured, your body temporarily prioritizes survival over perfect glucose control, even if you normally have very stable numbers,” says Scott Isaacs, MD, an Atlanta-based endocrinologist and immediate past president of the American Association of Clinical Endocrinology. “You can be doing everything right and still see your blood sugar spike during an illness. It’s not due to lack of discipline.”

Fortunately, understanding why blood sugar levels can become harder to manage during these situations can help you make a plan to respond more effectively.

“Illness or injury can set off the body’s natural stress hormone response that’s meant to keep you alive, fight infection, and promote healing. And one part of that response is raising blood sugar,” says Dr. Isaacs.

But in people with diabetes (diagnosed or not), this stress response can overshoot and lead to potentially dangerous elevated blood sugar levels.

It can also complicate day-to-day management for people who are already conscious about managing blood sugar, says Lisal J. Folsom, MD, an endocrinologist and the medical director of the adult endocrinology division of the Wendy Novak Diabetes Institute in Louisville, Kentucky. “The problem arises in insulin resistance, where the body either doesn’t make insulin or can’t make enough insulin to meet the increased demand,” she says. “This can result in persistently high blood sugars, which actually impede the healing response.”

Managing blood sugar is a delicate balance, even when you’re healthy and feeling great, says Dr. Folsom.

Lifestyle factors, such as diet, exercise, and sleep, can add another layer to this challenge:

• Diet is one of the most important tools for managing blood sugar, but your food intake may shift when you’re sick.

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  “With illness, you may have fever, nausea, vomiting, diarrhea, or decreased appetite,” says Folsom. “This can result in dehydration, decreased nutrition intake, and less fuel available for the body to make energy to fight off the illness and recover.”
• Exercise is a main component of blood sugar management, as physical activity typically helps lower blood sugar levels and improves insulin sensitivity. But you may not feel up to exercising — or may not even be able to move — while sick or recovering from an injury or surgery.

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• Sleep is also critical for regulating blood sugar levels, and experts generally recommend getting at least seven hours per night to support metabolic health.

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   But symptoms ranging from discomfort and pain to coughing and congestion can easily disrupt rest.

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• Monitor your levels. “Checking blood sugar more frequently or using a continuous glucose monitor gives you an opportunity to respond before blood sugar goes too high or too low,” says Isaacs.
• Adjust meals accordingly. Pay close attention to meal timing and portion sizes to help lessen large swings, especially if your appetite is off, Isaacs says.
• Consult your care team. Making a plan with your provider “will empower you to manage blood sugar and diabetes at home if symptoms develop at a time you’re not able to immediately contact them,” says Folsom.
• Incorporate gentle movement. “Even brief, gentle physical activity — like short walks around the house or light stretching — can improve insulin sensitivity and help you feel better, as long as it’s safe in the context of your illness or injury,” says Isaacs.
• Drink plenty of water. “Stay hydrated by frequently sipping water or sugar-free liquids if blood sugars are high or liquids that contain some carbs, like juice, if blood sugars are dropping,” says Folsom.
• Prioritize rest. Aim to get as much sleep as you can to support the healing process and stabilize blood sugar.
• Keep an eye on vital signs. Dropping weight without trying can be a sign of high blood sugar, so ask your doctor if you should consider weighing yourself regularly while you recover. Also, be sure to check your temperature every morning and evening, as fever can be a sign of infection, which can also interfere with blood sugar.
• Prepare ahead of time. Plan to keep enough insulin on hand, as well as any other diabetes medications you take. Stock up on a few weeks of easy-to-prepare foods, so you’re not scrambling during recovery.

Most important, Isaacs says, “If you’re seeing unexpected high or low glucose levels, you can’t keep fluids down, or you’re unsure of how to adjust insulin or other medications, contact your physician.”

• When you get sick, undergo surgery, or injure yourself, blood sugar levels may become more challenging to manage.
• The body’s natural immune response triggers elevated glucose levels during periods of stress and illness to support survival and recovery.
• During these periods, taking steps to monitor glucose levels, make meal and other lifestyle adjustments, and prioritize self-care can help regulate blood sugar and promote healing.