Health

3 Things Weakening Your Immune Response This Fall (That You Might Not Realize)

Dr. Jenny McMullen

Owner/Chiropractor

Are you feeling a little more rundown than usual this fall?

You’re not alone — this season is a common time for fatigue, brain fog, sleep disruption, mood dips, and of course, catching every cold that’s going around. But here’s the good news: these symptoms aren’t just random. And more importantly, they’re not inevitable.

As a holistic health practitioner and chiropractor, I’ve seen firsthand how the transition into fall can quietly strain the immune system — especially when our daily routines shift and we aren’t fully supporting the body’s needs.

Let’s talk about 3 surprisingly common (and fixable) reasons your immune system might be underperforming right now, and what you can do to stay well and resilient as the seasons change.

1. Sedentary Days = Stagnant Immune System

When the days get shorter and colder, it's easy to slip into a more sedentary routine. You’re indoors more. You’re moving less. And that slowdown doesn’t just affect your energy — it directly impacts your immune function.

Your lymphatic system, which plays a critical role in fighting infection and clearing toxins, relies on physical movement to function. Unlike your circulatory system, it doesn’t have a pump. It needs you to move in order to move.

When we’re sedentary, especially for long hours at a desk, in the car, or on the couch, lymphatic flow slows down, detoxification becomes sluggish, and our natural defense systems start to weaken.

Here’s what you can do:

Aim for at least 30 minutes of intentional movement per day(even a brisk walk counts)
Incorporate light stretching, rebounding, vibe plates or yoga to support lymphatic drainage
Set a timer to stand up and move every hour during your workday

Movement isn’t just about fitness — it’s foundational to immune health.

2. Low Vitamin D (Even If You're "Outside Enough")

We often think of vitamin D as a “nice-to-have,” but when it comes to the immune system, it’s essential.

Vitamin D plays a key role in activating immune cells and regulating inflammation. In fact, low vitamin D levels are associated with increased susceptibility to infections, including respiratory illnesses — the exact kind we tend to see more of in fall and winter.

The challenge? Even if you spend some time outside, sunlight levels naturally decrease in the fall, especially in certain climates. Plus, many of us are covered in more clothing and spending less time in direct sunlight — making it harder for the body to synthesize adequate vitamin D through the skin.

What you can do:

Get your levels tested — you don’t have to guess
Consider supplementing with a high-quality D3 + K2, like The Wellness Way’s
Aim for 15–30 minutes of sunlight daily when possible — ideally on bare skin

Vitamin D is simple to test and correct — and it can make a big difference in how you feel.

3. Hidden Sugar = Suppressed Immunity

Fall is full of seasonal treats — pumpkin spice lattes, baked goods, cozy cocktails, Halloween candy. And while a little indulgence isn’t a problem, it’s worth knowing that high sugar intake can significantly suppress your immune function for hours after consumption.

How? Excess sugar impacts the ability of white blood cells to do their job. It also contributes to inflammation, insulin resistance, and disruptions in gut health — all of which can leave your immune system compromised and sluggish.

This doesn’t mean you can’t enjoy fall flavors. It just means being intentional — and making swaps when you can.

Try this instead:

Choose naturally sweet treats like baked apples, herbal teas with cinnamon, or allergy friendly pumpkin muffins
Watch out for sneaky sugar in coffee drinks, sauces, and “health” bars
Balance sweet treats with protein, fiber, and healthy fats to prevent blood sugar crashes
Check out thewellnessway.com for healthy recipes

A more stable internal environment means your immune system can focus on what it does best: protecting you.

What If You’re Doing Everything Right… and Still Not Feeling Well?

This is a really common story when clients come into my practice. You’re eating well, moving your body, taking your supplements — but you still feel off.

Here’s why: you might be missing a key piece of the puzzle.

Symptoms like fatigue, frequent illness, poor sleep, skin flare-ups, and brain fog can all be signs of underlying immune dysregulation. And sometimes, no amount of surface-level fixes will get to the root of what’s going on.

That’s why we offer functional and comprehensive panels — Test’s that give us a deeper look at how your immune system is really functioning.

We can measure:

Inflammation levels
Immune overactivity or suppression
Nutrient deficiencies
Stress markers
Gut-immune interactions

Instead of guessing, we test — and create a plan that’s individualized to what your body needs.

You Don’t Have to Push Through This Season

If your body is asking for help, don’t ignore it. Small shifts now can prevent bigger health issues down the road.

Here’s what I recommend:

Start with the basics: daily movement, vitamin D, and reducing sugar
Tune in to your body — notice patterns in energy, digestion, sleep, and stress
If you’re unsure where to start or want to go deeper, book an appointment. We’ll guide you through testing, support, and a realistic wellness plan that fits your lifestyle.

Fall can be a beautiful, nourishing season — if your body has what it needs.

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