The leaves are falling, the light is fading, and so is our immune resilience. Every autumn I see the same pattern: coughs, colds, sore throats creeping in. It hit close to home last week when my little dog Stormzy spent four days in hospital with a fever.
The leaves are falling, the light is fading, and so is our immune resilience. Every autumn I see the same pattern: coughs, colds, sore throats creeping in. It hit close to home last week when my little dog Stormzy spent four days in hospital with a fever. Watching him, withdrawn, no appetite, no wagging tail, reminded me how universal this is. And here’s what's important: it’s not the virus that decides the outcome, it’s the host. Your immune system is the deciding factor. Let’s dive in...
Where insight becomes impact
What I’ve been looking at this week…
Here's a quick overview of your immune system. It's made up of two complementary forces.
Innate immunity: this is your rapid-response team - T-cells, macrophages, natural killer cells, complement proteins, cytokines like IL-6. They act quickly and broadly.
Adaptive immunity: this is your precision team - antibodies like IgG and memory T-cells. They remember past invaders and respond with accuracy.
And because immune cells are stationed at every barrier - gut, lungs, skin - your microbiome is critical. The microbes living inside and on you constantly train immune cells to tell the difference between harmless and harmful.
So why do autumn and winter bring more infections? Here's what's striking: the answer isn’t just “more viruses.” It’s also that your immune system is weaker when the days are shorter.
Here’s the mechanism:
As daylight shortens in autumn, your pineal gland produces more melatonin. Most people know melatonin as the hormone that helps you fall asleep, which it does, but it’s also a seasonal signal, telling your brain that the environment is shifting.
That signal is processed by the hypothalamus, the master regulator of your body’s rhythms: sleep, hunger, temperature, reproduction, and immunity.
From there, the hypothalamus communicates with the thyroid gland, which sets your metabolic tempo and influences how immune cells are produced and deployed. Too little thyroid drive, and immune responses slow. Too much, and they overshoot.
This light–melatonin–hypothalamus–thyroid circuit is what creates your seasonal immune clock. And a landmark UK Biobank study of more than 329,000 people, published in iScience in 2021, confirmed this with hard data: immune cell numbers and inflammatory markers rise and fall with both time of day and day length. Which means that just as more viruses start circulating in the autumn, your defences become seasonally weaker.
As autumn light fades, your baseline protection is automatically dialling down - which means it’s even more important for you to actively dial it up.
Track it to hack it.
What I’ve been monitoring this week
Here are three essential devices to use at home so you can detect and respond early to viruses this season:
1. Thermometer The classic tool, but with controversy. For decades, mercury thermometers were the gold standard. Accurate, reliable, but risky. Mercury is toxic, and breakages are bad news. Do you really want a mercury bulb in your mouth? Today's best options are:
Digital oral thermometers: safe, fast, precise. Can also be used under the arm for an axillary reading (and can be used in dogs rectally - though I would definitely advice against sharing the same thermometer with your dog!
In-ear thermometers: great for children, but angle matters.
Forehead/infrared thermometers: quick and touch-free, less precise.
2. Heart rate monitor Your heart rate often rises before your temperature does, a phenomenon called tachycardia. One of the earliest infection signs is a resting heart rate jumping 10+ beats above your baseline. Wearables like Oura, Apple Watch, Garmin, and Whoop detect this. Which means that if you’re someone who tends to push through, tracking your heart rate can stop you before your body crashes.
3. Red light device Viruses increase energy demand and can drain your mitochondria, which explains why catching a virus can feel you've been hit by a bus. That's where red light can help. Red and near-infrared light recharge mitochondria to produce more ATP, your energy molecule. Which means your immune cells have more energy to fight. A 10-minute evening red-light session can shift fatigue and inflammation, supporting faster bounce-back.
Together, these three devices give you foresight, feedback, and fuel.
From knowing to doing.
What this means for YOU…
Here’s your I.M.M.U.N.E .Playbook for autumn resilience:
I - Inhale Short bursts of fast, deep breathing followed by breath holds raise adrenaline. Adrenaline mobilises immune cells and sharpens their innate response, which means your system is primed before you’re exposed. Breathe in though your nose and out through your mouth rapidly 30 times then on the exhale hold your breath for as long as you can. Repeat 3 times.
M - Microbiome Around 70% of your immune system sits in your gut lining. Feed it with ferments like kefir or sauerkraut, fibres like leeks and garlic, and polyphenols like berries and green tea. This means your gut microbes keep training your immune system to stay responsive.
M - Mobilise Regular movement keeps immune cells circulating through blood and lymph. Just a short walk or stretch every hour ensures immune surveillance is active, which means cells are where they need to be when an invader appears.
U - Unplug Melatonin doesn’t only help you sleep, it directs immune timing. Following the 8-80 rule (80 minutes screen-free before 8 hours of sleep.) Raising melatonin means your immune rhythms stay in sync.
N - Nourishments Every immune response is a cycle of activate, attack, resolve. Three nutrients anchor that cycle: Vitamin D: the “on switch” for immune cells. Low levels make the whole response sluggish. Food sources: oily fish (salmon, mackerel, sardines), egg yolks, fortified dairy and plant milks.
Zinc: essential for T-cell development and function. Without it, your frontline cells can’t mature properly. Food sources: pumpkin seeds, oysters, crab, beef, chickpeas.
Omega-3 fatty acids: help resolve inflammation once the infection is controlled, which means faster recovery without lingering fatigue. Food sources: salmon, sardines, mackerel, anchovies, walnuts, flaxseeds.
E - Environment It's such a beautiful time of year to be outside. The Autumn colours. The crisp air. The blue skies. Get outside daily. Fresh air reduces viral concentration compared to indoor air, which means your exposures are lower and your rhythms sharper. 💼 Case in point: One of my clients came to see me in early September last year. Every autumn he followed the same pattern: infections that would knock him out for weeks, disrupting travel, delaying projects, and draining his energy just when the business year was at its busiest.We ran nutrient testing and discovered low omegas and zinc. We corrected those, strengthened his gut microbiome, and fine-tuned his sleep routine. As a result, for the first time in years he went through autumn and winter without a single infection — even while flying internationally.This September he was back for his re-test, already ahead of the curve. His results show he’s primed and protected, ready to face another season with his immune defences at full strength. Acting early is what makes the difference.
🎯 If you want to prime your immune defences before the seasonal dip fully sets in, or if you’re someone who always seems to succumb to autumn infections, then book a private online consultation and let's start to build your personalised immune plan. And if you’d like to see how your gut microbiome is shaping your immunity, you can also book a private online consultation to reveal the workings of your immune command centre.
Where you’ll find me…
Last week: I was speaking with several family offices on aligning health and wealth strategies. These are clients who understand that health preservation is wealth preservation, and that protecting longevity is as important as protecting legacy.
This week: I’m on stage at Pause Live, speaking about sleep, midlife energy, and immune rhythm. For many women in this life stage, regaining health is the lever that unlocks leadership. It ties in beautifully with my client work. One client recently doubled her deep sleep time after we personalised her evening routine based on testing and tracking. That kind of transformation is exactly what I’ll be sharing with the audience: how data-driven strategies can change both nights and days.
Next week: I’ll be in Birmingham, leading my workshop The Entrepreneur’s Edge: Biohacks for Business Brilliance. I always enjoy these close-knit sessions; they’re a chance to work closely with entrepreneurs who want their health to match the pace of their ambitions.
A thought to pause on…
“The true test of immunity isn’t avoiding infection, it’s how quickly you respond and recover.” Which means your focus this autumn should be on preparation, so your system rebounds faster and stronger every time.
Wishing you a wonderful week ahead! (that's 168 hours of your million hour life!) Dr Alka Be sure to send this email to anyone who you also want to live their longest, healthiest life!
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Take the free LQThis article is general education, not medical advice, and reading it does not create a doctor-patient relationship. If something has been going on for a while, please get it properly looked at by your own doctor.