9 Sneaky Things that Can Spike Your Blood Sugar Levels

Yeah, eating a ginormous bagel can send your blood sugar levels soaring, but you should also pay attention to these lesser-known triggers.

You’re vigilant about testing your blood sugar in the morning and before meals, and you’re pretty confident about knowing which foods or activities have a specific impact on your blood sugar levels. But it’s happened to everyone with diabetes at some point or another: an out-of-nowhere blood sugar spike. If it’s not because of a carb overload, what gives? Here are some less well-known everyday scenarious that can raise your blood sugar levels.

1. You got a shot at the doctor's office

Cortisone shots can provide temporary relief for that bum knee or arthritis pain in your hand, but they can also spike your blood sugar. “Cortisone shots deliver medication that is like the cortisol hormone produced by the adrenal gland. That hormone helps in times of stress by stimulating the liver to produce extra glucose,” says Susan Renda, a nurse practitioner and certified diabetes educator at Johns Hopkins. “The cortisone injection mimics this action and glucose goes up even though the person does not need additional glucose.”

Your blood glucose should return to previous levels, but it may take days or even weeks depending on the type of cortisone shot. Check in with your regular healthcare provider before you get a cortisone shot and see if any medication adjustments are needed. Monitor your glucose at home and be sure to report elevations to your doctor. “Staying hydrated and avoiding excess carbohydrates can also help,” says Renda.

2. You're being chased by a bear

OK, so you’re probably not literally running from a grizzly, but running to catch your commuter train, giving a presentation to your boss, or having an argument with your partner releases “fight or flight” hormones that stimulate the liver to release extra glucose. “The body assumes the stressful event means skeletal muscles may need more glucose (energy), such as if a bear were chasing you!” says Renda. Get a grip on your stress by practicing meditation, breathing exercises, yoga, journaling, or any calming activity to reduce these blood sugar spikes. Here’s more info on why stress management is so critical for diabetes care.

3. You're recovering from an injury

Chronic pain from an injury you sustained during a car accident or downhill skiing adds stress to the body, which increases the hormones that release glucose from the liver. Stress reduction techniques can help, but because the chronic pain is ongoing, pain control and/or adjustment of your diabetes medications may be necessary for blood sugar control. “This explains why a person who has had trauma such as a motor vehicle accident will experience higher than usual glucose levels and may even require insulin in the hospital and while recovering,” notes Renda.

4. You indulged in "diabetic" chocolate cake

Your friend was kind enough to make a “diabetes-friendly” cake just for you, but after you ate it, your blood sugar inexplicably spiked. It turns out, not all sugar-free foods are innocent for people with diabetes. “Sugar-free” or “no sugar added” foods tend to replace traditional sugar with sugar alcohols, such as sorbitol, maltitol, and xylitol. “In general from my experience, people with diabetes should avoid sorbitol and maltitol, as they have the highest risk for increasing glucose levels,” says Mona Morstein, naturopathic physician and author of Master Your Diabetes: A Comprehensive, Integrative Approach for Both Type 1 and Type 2 Diabetes.

Sugar alcohols can affect everyone differently, so it’s important that “everyone ingesting sugar alcohols should check their glucose numbers to ensure they are not affected by them,” says Morstein. The Diabetes Teaching Center at the University of California, San Francisco offers an easy formula for counting carbohydrates in sugar alcohols: Include half of the sugar from sugar alcohol as carbohydrates.

5. You're in bed with a fever

When you’re battling a bad cold or other pesky virus, a fever increases your metabolism, which results in more white blood cells flocking to fight the infection. But this immune response increases cortisol and adrenaline production in a response to stress in the body, which also raises blood sugar. “A fever can increase glucose due to the elevation in metabolism, and also, some cold/flu products may contain ingredients that raise glucose levels,” says Morstein. When you have diabetes, it’s important to work with your doctor to create a “sick day” plan before an illness strikes. When you’re ill, you’ll need to be especially vigilant about monitoring blood sugar levels. Always ask your doctor or pharmacist before you take any cold or flu medicines.

It's important to work with your doctor to make a sick day plan before illness strikes.

6. Your asthma is acting up

The prescription prednisone is used to treat asthma (as well as and other conditions such as arthritis and dermatitis). This is one of the most common medications that can raise blood sugar levels, says Paris Roach, MD, an endocrinologist at Indiana University Health. “This seems to be the result of the steroid increasing glucose production by the liver,” says Dr. Roach. Prednisone is also used to treat viral upper respiratory infections with prominent pulmonary symptoms. “This effect will persist through higher doses of oral steroids but will dissipate quickly; in a day or two, after steroids are tapered off. Diabetes medications can be temporarily administered or adjusted as necessary,” says Dr. Roach.

7. You're on vacay and it's insanely hot

You may not even be aware of how hot and humid it is if you have diabetes, says Dr. Roach, which is why some people with diabetes may not sweat as effectively as people without the metabolic disorder. This sticky scenario can lead to dehydration, which raises blood sugar levels. “To guard against dehydration, drink plenty of fluids, preferably non-glucose containing fluids—water is best—and try to stay in the shade as much as possible and limit time outside during the hottest parts of the day,” recommends Dr. Roach. Watch for these other sneaky signs of dehydration.

8. Your period is coming

If you’ve noticed fluctuations in your blood sugar, but can’t put your finger on the culprit, your period—or menopause—could be to blame. “The amount of estrogen and progesterone released by the body may affect the way that the body processes or responds to insulin,” says Joanne Rinker, MS, RD, director of practice and content development for the American Association of Diabetes Educators. “This can cause fluctuations in blood sugar and would be prevalent during either menopause or menstruation,” says Rinker. The spikes can be hard to predict because sometimes periods aren’t regular, especially if you are transitioning into perimenopause or menopause. “One possible prevention is hormone regulation,” says Rinker. Adjusting diabetes medication at different stages in your menstrual cycle can help keep blood sugar levels in check.

9. You've guzzled coffee after a late night

Who hasn’t poured an extra mug (or three) of coffee on one of those mornings when you just did not want to get out of bed? The extra caffeine jolt can spike more than just your energy. “Disrupted sleep can increase stress hormones, namely cortisol, which would result in reduced insulin sensitivity and increased blood glucose levels,” says Minisha Sood, MD, an endocrinologist specializing in diabetes at Lenox Hill Hospital in New York City. Even if you rested well, caffeine can lower sensitivity to insulin. “If you notice blood glucose increases after caffeine intake, it’s best to avoid or reduce your caffeine consumption,” suggests Dr. Sood. Here are other signs you might be drinking too much coffee, as well as tips on how to make your coffee habit healthier.