Glucose is a simple sugar that acts as a primary source of energy for the body's cells. The body usually gets it from the food we eat, particularly carbohydrates. Several factors can affect glucose levels in the body. These include diet, physical activity, stress, medications, and certain illnesses. Hormones like insulin, glucagon, and cortisol also play a crucial role in regulating glucose.
However, one often overlooked factor is seasonal changes, which refer to the variations in climate and day length that occur throughout the year. The OnlyMyHealth team interacted with Dr Kashish Gupta, Consultant Endocrinologist, PSRI Hospital, Delhi, to understand the connection.
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How Seasonal Changes Cause Glucose Level Fluctuations
"Seasonal changes, including temperature and daylight, can have a measurable impact on blood sugar levels, especially in individuals with diabetes," said Dr Gupta, adding that colder weather may lead to increased insulin resistance due to reduced physical activity and higher stress levels, which can elevate blood glucose.
In contrast, during warmer months and longer daylight hours, people tend to be more active, which helps lower blood sugar through improved insulin sensitivity.
Moreover, fluctuations in daylight can affect circadian rhythms, which influence hormonal balance, sleep quality, and appetite – all of which play roles in glucose regulation. "Some individuals may find their blood sugar levels slightly higher in winter and better controlled during spring and summer," Dr Gupta added.
Research also suggests that blood glucose levels may be higher during monsoon season. A 2024 study published in Practical Laboratory Medicine tracked the blood sugar control of over 8,000 patients for a full year. They looked at the HbA1c test results and discovered a unique pattern not typically seen in other parts of the world: patients' blood sugar levels were generally highest during the rainy monsoon season and lowest in the autumn. The researchers believe this spike during the monsoon could be linked to people getting less outdoor exercise and changing their diets due to the weather.
Are Diabetes Patients More At Risk Of Seasonal Glucose Fluctuations?
People with type 1 and type 2 diabetes both are more susceptible to seasonal fluctuations in glucose levels, according to Dr Gupta, who shares that their bodies are already less efficient at managing blood sugar, so any external changes, such as variations in physical activity, diet, or sunlight exposure, can cause noticeable shifts.
“For example, in winter, increased calorie consumption and decreased activity can lead to higher glucose levels. Shorter daylight hours and cold-related stress can also trigger hormonal responses (like elevated cortisol), which can further disrupt glucose control. These changes may not affect everyone the same way, but those with existing metabolic imbalances are certainly more vulnerable,” he explained.
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Do Seasonal Changes Also Alter Insulin Needs And Medication Requirements?
In many cases, yes, said Dr Gupta. He shared that seasonal changes can necessitate adjustments in insulin dosage or oral diabetes medications. For instance, during the summer, when people tend to be more active and may eat lighter meals, insulin sensitivity can improve, requiring less medication.
Conversely, in colder months when activity decreases and calorie intake rises, higher doses may be needed.
“These changes should never be made without consulting a healthcare provider. Frequent monitoring of blood glucose, either through finger-prick tests or Continuous Glucose Monitoring (CGM), is essential to detect these seasonal patterns and respond appropriately under medical supervision,” the doctor added.
Role Of Diet And Lifestyle Choices
Diet plays a crucial role in regulating glucose levels, impacting both the rate at which glucose enters the bloodstream and how the body utilises it.
Carbohydrates, in particular, have a great influence on blood sugar levels as they are broken down into glucose. However, the impact varies based on the type of carbohydrate, the presence of fibre, and the presence of other macronutrients like protein and fat in the meal.
According to Dr Gupta, maintaining a consistent diet and regular physical activity year-round is key to minimising seasonal variations in glucose levels. "In winter, when people tend to indulge in heavier foods, focusing on portion control, balanced meals, and fibre-rich options can help regulate sugar absorption. It’s also important to limit sugary comfort foods and alcohol, which are more commonly consumed during holidays and colder months."
He further added that physical activity remains one of the most effective tools for blood sugar control. If outdoor exercise isn’t practical in cold weather, indoor alternatives such as yoga, strength training, or aerobic workouts should be incorporated.
Signs Of Glucose Level Fluctuations During Seasonal Changes
Seasonal transitions can subtly affect the body, and it’s important for people with diabetes to remain vigilant, advised Dr Gupta.
Signs to watch for include:
- Unusual fatigue
- Increased thirst
- Frequent urination
- Blurred vision
- Slow healing of minor wounds
- Unexpected changes in weight
- Fluctuations in mood or sleep patterns
These symptoms may indicate poor glucose control or the need for medication adjustment. During the fall and winter, people with diabetes should be aware of the risk of diabetic retinopathy progression, as high glucose levels during colder months can worsen microvascular complications, including damage to the eyes.
Conclusion
Many factors can affect glucose levels in the body. However, seasonal changes are an often overlooked cause of glucose fluctuations in the body, especially in people with diabetes. While warmer months are said to support blood sugar management and maintain stable glucose levels, winter and the monsoon season are believed to contribute to the highest glucose level fluctuations. According to experts, healthy lifestyle choices, like eating a balanced diet and engaging in regular physical activities, are the best ways to regulate glucose levels in the body, regardless of what season it is.