Fall into Stable Blood Sugars: Adapting to Seasonal Shifts

Fall into Stable Blood Sugars: Adapting to Seasonal Shifts
As summer winds down and the crisp air of autumn sets in, those of us managing Type 1 Diabetes face unique challenges, and opportunities, to keep our blood sugars steady. Seasonal shifts can affect everything from insulin sensitivity to meal timing, exercise routines, and even the foods we crave. Drawing on both science and my own experience, this post is meant as a comprehensive guide to help you transition smoothly into fall and maintain stable glucose control. Not all of these things WILL happen or ARE helpful, but some of them could be game changing!

Embracing the Season: Why Fall Demands a Fresh Approach
Autumn brings cooler temperatures, changing daylight hours, busy back-to-school schedules, and an abundance of seasonal produce. Each of these factors can influence your blood sugar in different ways.

Temperature affects insulin sensitivity. Daylight saving shifts your circadian rhythms, altering meal and insulin timing. Routine changes, kids back in school, new work schedules, all of these impact meal patterns and stress levels. Fall flavors like apples, squash, and pumpkins introduce new carb-counting challenges.

Recognizing these shifts allows you to anticipate changes and adjust proactively rather than reactively.

Temperature & Insulin Sensitivity

Cooler Days, Increased Sensitivity

Studies show that colder temperatures can enhance insulin sensitivity, meaning your insulin might work more effectively to lower blood sugar. You may notice steadier post-meal glucose curves, but also a higher risk of hypoglycemia, especially overnight.

What you might consider: You could review your basal rates and consider a 5-10% reduction in basal insulin on consistently cool days. Monitoring closely by checking blood sugars before bed and early morning can help you catch unexpected lows.

Warm Spells & Resistance
Autumn often includes warm days too. Heat can increase insulin absorption at infusion sites, but it can also promote inflammation, potentially raising blood sugars.

REMINDER: You might experience the exact opposite in your blood sugar due to weather, and that's okay. Rely on your body's trends primarily.

What you might consider: Rotating sites frequently could help, especially avoiding areas that will get hot under heavy clothing. If you spike after meals in warm weather, you might try delaying your bolus by 5-10 minutes to see if that helps.

Daylight Saving & Circadian Rhythms
When clocks "fall back," our internal clocks can take days to adjust. Circadian misalignment can alter insulin sensitivity peaks (often higher in early morning), meal timing with later breakfasts or dinners, and sleep quality, which influences blood sugar regulation.

What you might consider: In the week leading up to DST, you could shift meal and bedtime by 10-15 minutes each day if you want a seamless transition. Maintaining your usual pre-bolus timing relative to meals (even if the clock changes) can help keep things stable. Testing before bed and upon waking for a few days post-DST gives you extra data to work with.

Back-to-School Routines & Stress
September often heralds a return to school and work routines, bringing both structure and stress. Stress elevates cortisol, which can spike blood sugar.

What you might consider: Morning check-ins by testing blood sugar when waking and before school or work can help you set a stable foundation. Carving out scheduled mid-morning and mid-afternoon snack breaks, and pre-portioning carbs, can prevent surprises. Incorporating even 5 minutes of mindfulness or breathing exercises before high-pressure tasks might help manage stress-related spikes.

Fall Produce & Carb-Counting Challenges
Autumn's bounty offers delicious variety but also carb-counting puzzles. One medium apple might contain around 25g of carbs. Winter squash like butternut or acorn could have about 15g of carbs per cup when cooked. Pumpkin, especially canned, might have around 12g per half cup, but beware of sugar-spiced recipes that can increase this significantly.

What you might consider: Using a food scale for new foods until you know their carb count can be really helpful. Pairing starchy vegetables with protein and fat (like roasted squash with chicken) might help blunt spikes. If you're baking, you could try substituting half the regular flour with almond flour to lower the overall carb count.

Basal & Bolus Adjustments
Fine-tuning both basal and bolus insulin is crucial for seasonal transitions.

Basal Tweaks
Cool nights might mean reducing basal by 5-10%. On warmer days, you might monitor for resistance and consider a slight increase if you're seeing persistent highs.

Bolus Timing
Dense fall meals like stews and casseroles digest slowly. You might try splitting your bolus: half upfront and half 1-2 hours later. Quick fall carbs like apple juice or sweetened drinks still might benefit from standard pre-bolus timing, around 10-20 minutes before consuming.

Hydration: Cold Doesn't Mean Quench-less
Hydration often dips as temperatures fall, but staying hydrated remains critical for blood sugar stability. You might aim for 8-10 cups of water daily, even if you don't feel as thirsty. Adding flavor with cinnamon-steeped water or a splash of unsweetened apple juice can make it more appealing. Monitoring for concentrated urine (darker color) can signal you need more fluids.

Fall Fitness: Adapting Exercise & Insulin

Changing seasons shift your activity patterns in different ways.

Outdoor workouts: Cooler weather may prompt longer runs or hikes. You might consider lowering basal by 20-30% about 30-60 minutes before prolonged cardio.

Indoor classes: If you shift to gym workouts, tracking how each type affects your glucose differently from outdoor exercise can help you fine-tune your approach.

Holiday prep: Beginning mindful carb and insulin tracking before October's holiday season might help you avoid last-minute chaos.

Preparing for Holidays & Gatherings

Autumn previews the busy holiday season. Early planning can prevent carb surprises.

Recipe testing: Trying holiday recipes at home first, logging carb counts and adjusting doses, gives you valuable data for the actual event.

Portion control tools: Bringing your own measuring scoop or plate divider to potlucks can help you estimate more accurately.

Pocket snacks: Carrying a low-carb snack in case options are limited ensures you're never caught without a backup plan.

Mindset & Self-Compassion
Seasonal changes can feel overwhelming. Remember that small adjustments matter. A 5% basal tweak or a 10-minute pre-bolus shift can stabilize entire days. Validate your efforts because fall brings chaos, and adapting is a win. Celebrate your resilience because every day you stay in range despite the shifts is a victory.

Quick Summary
Autumn affects T1D management in multiple ways. Cooler temps can change insulin sensitivity, daylight savings might shift your rhythms, back-to-school stress can spike cortisol, and fall foods challenge carb counting. Tweaking basals, pre-bolusing wisely, staying hydrated, and planning for holidays can all help keep your sugars more stable.

Diabetes is tough, but so are you. So remember, you've got this.
Stay fun,
Madi Cheever, MPH, RD, LDN, CHES
Type One Type Fun

DISCLAIMER: Although I am a healthcare professional, this post is not intended to be medical advice. This is simply me sharing some of what I know, but your body may not respond in this way, so please make sure you are chatting with your diabetes educator and/or doctor first, or bring me onto your care team 😘