When people think about blood sugar spikes, the first thing that often comes to mind is food – especially sugary snacks or high-carbohydrate meals. However, fluctuations in blood glucose are not always driven by what you eat. Everyday factors such as stress, sleep patterns, physical activity, illness, and even hormonal changes can also influence how the body regulates glucose. In some cases, these spikes are temporary and part of the body’s natural response to certain situations rather than a cause for concern.
Dr Amir Khan, a general physician working with NHS England, resident doctor on ITV’s Lorraine and Good Morning Britain, and host of the No Appointment Necessary podcast, has highlighted five reasons your blood sugar can spike beyond just the food you eat. In an Instagram video shared on March 14, the physician highlights, “Did you know your blood sugar can spike even if you haven’t had a single bite to eat? Let me share five surprising things that can raise your blood sugar and why it might not always be a bad thing.”
1. Stress
According to Dr Khan, stress triggers a rise in cortisol levels, activating the body’s fight-or-flight response. This, in turn, signals the liver to release stored glucose into the bloodstream to provide a quick boost of energy. As a result, the surge of glucose can cause blood sugar levels to rise.
He explains, “When you’re stressed, your body releases cortisol, the fight or flight hormone that tells your liver to release stored glucose to give you energy. Great if you’re running from a tiger, less helpful if you’re just stuck in traffic. Remember, chronic stress equals chronic glucose spikes and that is not good for long-term health.”
2. Poor sleep
The physician highlights that even a single night of poor sleep can increase insulin resistance, meaning glucose stays in the bloodstream for longer and leads to elevated blood sugar levels. He warns that chronic sleep deprivation can significantly raise the risk of developing type 2 diabetes, even in people who otherwise try to maintain a healthy diet.
He explains, “One bad night, your body becomes more insulin resistant. That means glucose hangs around in the blood for longer and over time, poor sleep can increase your risk of type 2 diabetes, even if you try your best to eat well.”
3. Exercise
Even exercise can temporarily spike blood sugar, but according to Dr Khan, this is not necessarily a bad thing. Certain forms of physical activity, particularly intense or resistance training, can prompt the body to release more glucose into the bloodstream to fuel the muscles. However, the physician emphasises that regular exercise ultimately improves insulin sensitivity over time, helping the body regulate blood sugar more effectively.
He highlights, “Number three, exercise. Yes, even the good stuff. Certain types of exercises, especially intense or resistance training, can temporarily raise your blood sugars. Why? Well, again, it’s your body releasing glucose for fuel, but really importantly, long-term, exercise improves insulin sensitivity, meaning lower blood sugars overall. So, this is not a bad spike.”
4. Infections or illness
The physician explains that when the body is fighting off an infection, it releases more glucose into the bloodstream to help fuel the immune system. This is why people with diabetes often notice higher blood sugar levels when they are unwell. However, he emphasises that this response is completely normal as the body works to combat illness.
Dr Khan explains, “When you’re fighting off a bug, your immune system has to ramp up, and that comes with a glucose surge. It’s your body’s way of fueling the immune response. People living with diabetes often notice higher blood sugar levels when they’re unwell. That’s totally normal and they may have to adjust their medication accordingly.”
5. Hormones
Dr Khan notes that hormonal fluctuations during different phases of the menstrual cycle can also influence blood sugar levels. Higher progesterone during the luteal phase can make cells more insulin resistant, which may lead to elevated blood sugar. In addition, declining oestrogen levels during perimenopause and menopause can further reduce insulin sensitivity, affecting how the body regulates glucose.
He explains, “Ladies, this one’s for you because it’s mainly around your periods or the menopause. In the second half of your menstrual cycle, that’s the luteal phase, progesterone levels rise. This can make your cells more insulin resistant, meaning higher blood sugars. And of course, in perimenopause and the menopause, oestrogen levels decline, and that comes with insulin sensitivity dropping. So you become more resistant to insulin, leading to more frequent spikes in blood sugar. That’s why women in their 40s and 50s may notice weight gain, fatigue, or brain fog which can be linked to blood sugar shifts.”
Dr Khan concludes, “So remember, not all blood sugar spikes are bad. Context matters. But if you’re seeing high readings and you’re not sure why, it’s always worth talking to your doctor and it’s not always about what you’re eating.”
Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. It is based on user-generated content from social media. HT.com has not independently verified the claims and does not endorse them.
