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The hidden toll of stress: how it affects your health and what you can do about it
Build your health, reclaim your freedom (Issue #129)
Marcus Frick
May 17, 2025
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Read time: 10 minutes
Good morning, 66.1ers.
As mentioned, we’ve moved from Substack to beehiiv. If anything looks funky with your subscription, please reply here and let us know.
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As with all Saturday issues, today’s newsletter is paid.
If you’d like to hear my thoughts + scientific insights on:
How stress affects your sleep
The negative effects of stress on your immune system
Why stress might be the culprit if you’re dealing with unwanted weight gain
And access the visual that will help you master stress, increase productivity, AND get your sleep
Access to the podcast-style of this recording
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Paid subscribers: you’ll find the podcast-style recording of today’s issue a little further down.
Setting the scene:
I’ve been thinking a lot about stress lately. What is “stress”? What do people mean when they’re “stressed out”? What is going on in your body when you’re “stressed out”?
As we continue to ramp up production at Freedom Fats (I’m a co-founder) and I’m still working at Mayo Clinic during the day and coaching a few private clients, I’ve run into days when it feels as though I’ll never get through the work required. Stressful is the word. If I’m not careful, my caffeine consumption goes from 1.5 cups/day to 3.5 cups/day. My sleep quality tanks. I’m short-tempered.
It’s not a great way to live, especially considering I’m pre-kids, early in my career, and have more “free” time than I ever will until I retire. With all that in mind, it’s imperative I figure out this stress management challenge once and for all.
The past couple weeks have led me to wonder about 2 questions:
What’s actually going on in your body when you’re stressed?
How to mitigate the effects of stress without pausing the work I care about?
If you’ve got your stress managed, today’s issue isn’t for you.
If you would like to be a little more Zen (or just a little less nervous), today’s issue should help.
Here’s the recording link for today’s episode:
Stress and your sleep
You’ve probably been there: lying awake at night, your mind racing, despite having woken up at 5 AM. It’s now 10 PM and you’re still wired. It’s a combination of knowing that you’ve barely scratched the surface of your “to-do” list, drinking coffee until the late afternoon hours, and worry that something’s going to slip through the cracks.
In the past month, I’ve found myself lying awake thinking about our recent migration of 66.1 from Substack to Beehiiv, advertising strategies for Freedom Fats, and opportunities to better support coaching clients on their journeys to building sustainable health.
Enough about me, though. Science always has the last word here at 66.1. You’ve probably heard about cortisol, also known as the “stress hormone”. Stress causes your body to produce more of it. It gets you amped up, activating your sympathetic (fight-or-flight) nervous system. Super valuable if you’re engaged in strenuous activity
Unfortunately for your sleep, cortisol suppresses melatonin, your body’s natural sleep hormone. Not good.
Stress and your immune system
Ever get sick right after a particularly stressful period? Maybe it was after holiday travel, a particularly busy period at work, or a job transition. That wasn't just bad luck. Research consistently shows that chronic stress suppresses immune function, making us more vulnerable to everything from the common cold to more serious infections.
How does this happen? When cortisol remains elevated for extended periods, it reduces the number and effectiveness of white blood cells, particularly natural killer cells that fight viruses and certain types of cancer cells. Stress also increases inflammation throughout the body, which, when chronic, can contribute to numerous health problems.
A study published in Current Directions in Stress and Human Immune Function (2015) found that chronically elevated cortisol can lead to the immune system becoming "resistant," resulting in an accumulation of stress hormones and increased production of inflammatory cytokines that further compromise immune response. Research in the Journal of Clinical Medicine also demonstrated that elevated levels of stress hormones, particularly cortisol, can suppress the activity of key immune cells and skew cytokine production, ultimately compromising the body's ability to fight infections (Immunology of Stress: A Review Article, 2023).
If you’re prone to frequent colds or lingering infections, your body just might be telling you that stress is taking a toll.
Here’s an all-time favorite TED video of mine about how stress affects your body (including your immune system):
Stress and body composition
Here’s another one I’ve noticed lately, and one I’ve seen with many clients: stress leads to higher levels of body fat. Elevated cortisol levels signal your body to store fat, especially visceral fat that accumulates around your vital organs.
This happens for several reasons:
Cortisol increases appetite, particularly for high-calorie, high-fat, high-sugar "comfort foods"
Stress slows metabolism, meaning you burn fewer calories at rest
Cortisol promotes fat storage, especially in the abdominal area
Chronic stress can reduce motivation for physical activity
A groundbreaking study published in Psychosomatic Medicine found that women with central fat distribution secreted significantly more cortisol during stressful situations than women with lower waist-to-hip ratios, suggesting a direct link between stress reactivity and abdominal fat (Epel et al., 2000). It’s an old study, so this information is to be taken with a grain of salt. Correlation doesn’t necessarily mean causation. Another study in the International Journal of Obesity demonstrated that higher body fat percentage is associated with increased cortisol reactivity in response to emotional stress (Mujica-Parodi et al., 2009). Research from the journal Obesity Research also revealed that stress-induced cortisol secretion may contribute to central fat and demonstrates a clear link between psychological stress and risk for disease.
You’re probably convinced by now that stress isn’t improving your health. Here are 4 habits you can incorporate into your daily routine to reduce stress levels and reclaim your health.
Breaking free: 4 simple habits to reduce stress
Establish a wind-down routine
Create a 30-minute buffer between your daily activities and sleep time. Put away electronics (phone included), dim the lights, and engage in calming activities like reading, gentle stretching, or listening to soothing music. This signals to your body that it's time to transition from "alert mode" to "rest mode."
This habit is particularly important for those of us who tend to work or catch up on household tasks right up until bedtime, never giving our nervous systems a chance to downshift.
Empty your brain
When I’ve got a racing mind, I solve it by writing. Especially before bed, it’s important to get your thoughts out of your mind and onto paper so you can rest easy.
Spend 5-15 minutes before you get into bed writing reflections on the day, action items for tomorrow, and anything else rattling around in your brain.
Limit Information Consumption
Our 24/7 news and social media culture can keep us in a state of constant alertness. Try designating specific times to check news and social media, rather than consuming information continuously throughout the day. Many parents and grandparents find that a "digital sunset"—turning off news and social media at least two hours before bedtime—dramatically improves both stress levels and sleep quality.
Get outside
Research shows that spending just 20 minutes in nature significantly lowers cortisol levels. Whether it's a walk in a local park, gardening in your backyard, or simply sitting under a tree with a book, connecting with the natural world has powerful stress-reducing effects.
As a bonus, many nature activities also involve gentle physical movement and exposure to natural light, both of which support healthy sleep patterns and immune function.
What’s your go-to stress busting habit?
Reply here and let me know.
Have a question about stress?
Send it my way—I’ll tackle it in this month’s Q&A issue.
That’s all for this Saturday.
Seen you on Wednesday.
Have fun out there.
Marcus
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