Optimizing your surroundings
One of the most consistent patterns we see at A3 across hundreds of clients and thousands of data points is chronic stress. Not the acute, productive kind, but the low-grade, always-on kind that shows up in suppressed HRV, cortisol that never quite normalizes, and performance that degrades over time. We think of it as the unsung tax on high achievement. This series is a deep dive into a full stack of evidence-based interventions for doing something about it. As we said in Part 1, the research is clear: while there may not be a single magic bullet, multiple moderate interventions quickly add up.
Part 1 covered the entry point: breathing and mental practices. Part 2 tackled the foundations: exercise and sleep. Those are the things you do, the active interventions that require your time and attention.
This post is about something easier to overlook: your surroundings.
We spend enormous energy optimizing our habits and behaviors, but comparatively little attention on the environments that shape them. Yet some of the most reliable interventions we've seen aren't about willpower or discipline at all. They're about design.
Take nutrition, another big focus with our clients. Keeping healthy snacks visible and accessible, adding friction to the crappy stuff, designing your kitchen so the easy choice is the good choice. These changes don't require daily discipline. They work because they change the default.
The same principle applies to stress. Like fish who don't notice water, we tend to be blind to the environments we're immersed in, even as those environments continuously shape our physiology and behavior.
This post covers three layers of environment that affect stress resilience:
Temperature: deliberate hot and cold exposure as training stimuli;
Physical surroundings: air quality, light, noise, and the spaces you inhabit; and,
Social environment: the people around you, and why they might be the most important environmental factor of all.
Let's get into it.
Temperature
In Part 2, we touched on bedroom temperature as a lever for deep sleep. But temperature manipulation goes far beyond keeping your room cool at night. Deliberate exposure to thermal stress—both cold and heat—is one of the most powerful (and underutilized) tools in the stress resilience stack.
The mechanism is, again, hormesis: controlled, recoverable stress that builds adaptive capacity. Cold and heat work through different pathways, but both train your body's stress response systems in ways that carry over to other domains.
Cold Exposure: Dramatic Effects, Accessible Entry Points
The research on cold exposure is striking. A landmark study by Šrámek found that one hour of immersion at 14°C (57°F) produced a 530% increase in norepinephrine and a 250% increase in dopamine above baseline. These aren't small effects; they far exceed what any supplement can produce. And unlike pharmacological interventions that cause brief spikes followed by crashes, cold-induced elevations are prolonged and sustained.
That said, you don't need hour-long ice baths to benefit. Susanna Søberg's research identified the minimum effective dose: approximately 11 minutes total per week, spread across 2-4 sessions of 1-5 minutes each, at temperatures between 50-59°F (10-15°C). That's achievable with cold showers, an outdoor cold plunge, or even a chest freezer conversion if you're committed.
A few practical notes:
End on cold. If you're alternating between hot and cold (sauna then plunge, or hot and cold shower, for example), finishing with cold rather than warming up afterward appears to maximize brown fat activation and metabolic benefits.
The stress response habituates, but the benefits remain. Over 4+ weeks of regular cold exposure, your cortisol and ACTH response to the cold diminishes. You stop experiencing it as stressful. But the benefits (boosted norepinephrine and dopamine) persist. You're training your system to produce the upside without the downside.
Timing matters for strength training. Cold water immersion immediately after resistance training can blunt muscle growth (or hypertrophy), by interfering with the protein synthesis signals that drive adaptation. If you're doing both, do cold exposure on separate days, or either before or 6-8+ hours after lifting.
Cold showers are a legitimate entry point. A large Dutch RCT (n=3,018) found that just 30-90 seconds of cold showering reduced self-reported sick days by 29%. Interestingly, there was no dose-dependent difference between 30, 60, and 90 seconds—minimal exposure was enough to move the needle. If you're not ready for full immersion, a cold shower finish is a great place to start.
Sauna: The Long Game
If cold exposure is about acute activation, sauna is about long-term resilience. The research here is anchored by the Kuopio Ischemic Heart Disease Risk Factor Study—a 20+ year follow-up of 2,315 Finnish men that remains one of the most impressive datasets in lifestyle medicine.
The findings: compared to once-weekly sauna use, 4-7 sessions per week was associated with a 63% reduction in sudden cardiac death, 50% reduction in fatal coronary heart disease, and 40% reduction in all-cause mortality. Sessions exceeding 19 minutes at 80-100°C (176-212°F) showed the greatest benefit.
These are massive effect sizes—larger than most pharmaceutical interventions for cardiovascular risk. And while the study was observational (you can't easily randomize people to decades of sauna use, especially in a country where it's stranger if you don't sauna), the dose-response relationship and biological plausibility make a strong case that the sauna itself is driving outcomes, not just healthy-user bias.
Beyond cardiovascular effects, sauna produces acute hormonal shifts. Growth hormone increases 2-5x with standard protocols, and up to 16x with more aggressive approaches (four 30-minute sessions in a single day with cooling periods between). These effects diminish with habituation, but the cardiovascular and longevity benefits appear to persist with consistent use.
One practical application: sauna 1-2 hours before bed can enhance sleep by raising your core temperature, which then facilitates a steeper drop as you cool down—the same mechanism as the warm bath we mentioned in Part 2. If you have access to a sauna and struggle with sleep onset, evening sessions are worth the experiment.
Access is the main barrier. Unlike cold exposure (where a cold shower is always available), sauna requires either a gym membership with decent facilities, a spa, or a significant home investment. If you have access, the evidence suggests using it frequently (3-4+ times per week) is where the benefits really accumulate. If you don't, this isn't something to stress about. The other interventions in this series will still move the needle.
Physical Surroundings
Temperature is the most dramatic environmental lever, but it's not the only one. The spaces you inhabit, whether your office or home, continuously shape your physiology in ways that are easy to ignore precisely because they're constant.
Air Quality: The Invisible Drag
Most people never think about the air they're breathing indoors. That's a mistake.
Carbon dioxide levels are the clearest example. Outdoor air sits around 400 ppm CO2. But indoor spaces, especially poorly ventilated ones, accumulate CO2 quickly from human respiration. Studies show that at 1,000 ppm, cognitive performance begins to decline across multiple domains (decision-making, strategic thinking, information processing). At 2,500 ppm, strategic thinking becomes what researchers describe as "dysfunctional."
Conference rooms regularly exceed 2,000 ppm within an hour of a meeting starting. Home offices with closed doors aren't much better. You're not imagining that you feel foggy after a long meeting in a stuffy room; you're experiencing measurable cognitive impairment.
The fix is straightforward: ventilation. Open windows when possible. Take breaks that get you into fresh air. If you work from home, don't keep your office door closed all day.
A CO2 monitor ($100-200) is one of the highest-ROI purchases in this entire series. It makes the invisible visible. Once you see your levels climbing past 1,000 ppm, you'll actually open the window. The data changes behavior in a way that abstract knowledge doesn't.
Light: Beyond the Morning
In Part 2, we covered morning light as a circadian anchor. But light environment matters *throughout* the day.
Bright light during daytime hours—especially in the morning and midday—reinforces circadian rhythms and supports alertness. Dim light in the evening, particularly in the 2-3 hours before bed, allows melatonin to rise naturally. The problem is that modern life inverts this: we spend days in dim offices and evenings bathed by screens.
The practical fixes are intuitive: maximize natural light during work hours (sit near windows, take outdoor breaks), and dim your environment in the evening (prioritizing floor lamps rather than overhead lights). Night mode on devices helps marginally, but the bigger lever is overall light levels in your space.
Blue light blocking glasses have become popular, but the evidence is mixed. Studies in healthy adults show minimal objective improvement in sleep outcomes. Put simply, they're not harmful, but they're also not a substitute for actually turning off screens and turning down the lights.
Creating a Serene Space
This one will sound soft compared to cold plunges and CO2 monitors, but the research supports it: your visual and auditory environment affects your stress physiology.
Chronic noise exposure is associated with elevated cortisol and increased cardiovascular risk. Cluttered, chaotic environments are linked to higher baseline stress and impaired focus. Conversely, exposure to natural elements, like plants, natural materials, and views of greenery, produces measurable reductions in stress markers.
The practical application isn't about achieving touch-grass perfection. It's about reducing unnecessary friction in the spaces where you spend the most time:
Noise: If you work in a loud environment, noise-canceling headphones are a legitimate stress intervention, not just a productivity tool. If you control your space, consider background white or brown noise to mask irregular sounds.
Visual clutter: You don't need to Marie Kondo your entire life. But your immediate workspace (the desk, the room you're in most of the day) is worth keeping reasonably clear. The cognitive load of visual chaos is real.
Natural elements: A few plants, natural light, a view of something green if possible. These aren't luxuries. They're low-cost environmental modifications with documented effects on stress and focus.
This might feel like a lower priority than the other interventions in this series. But environment is cumulative. A chronically noisy, cluttered, artificially-lit space is a constant low-grade stressor. Exactly the kind of always-on load we're trying to reduce.
Aromatherapy: Surprisingly Legit
We'll be honest: aromatherapy sounds like it's one step away from crystals and intention candles. But the research is harder to ignore than expected.
A meta-analysis of 65 randomized controlled trials found that lavender inhalation reduces anxiety with an effect size of g = -0.73. That's a large effect, comparable to some pharmaceutical interventions. Oral lavender oil (Silexan, a standardized pharmaceutical-grade extract) has been shown in clinical trials to be comparable to lorazepam 0.5mg for anxiety, without the sedation or dependency risk.
You don't need the pharmaceutical version to benefit. A simple diffuser with lavender essential oil costs $30-50 and, based on the research, produces real acute effects on stress and anxiety. The inhalation route works within minutes.
Especially for acute stress moments or winding down before sleep, it's worth considering. Turns out, sometimes the soft interventions have hard data behind them.
Social Environment
We've covered temperature, air quality, light, and the spaces you inhabit. But there's one more layer of environment that matters more than any of those. And it's the one most likely to get deprioritized when life gets busy: the people around you.
Social Connection: The Irreplaceable Intervention
Here's a statistic that should stop you cold: social isolation carries a mortality risk comparable to smoking 15 cigarettes a day. It's a larger risk factor than obesity, physical inactivity, or air pollution. And yet we treat social connection as a luxury, something to fit in after work is done, if there's time.
The physiological effects are direct and measurable. Partner support during acute stress significantly reduces cortisol response. Close social bonds are associated with higher HRV, lower inflammation, and better immune function. Loneliness, conversely, is associated with elevated cortisol, increased sympathetic activation, and impaired sleep.
This isn't about being extroverted or having a large social network. The research consistently shows that quality matters far more than quantity. A few close, supportive relationships are more protective than a broad but shallow social circle. What matters is feeling genuinely connected, having people who know you, who you can be honest with, and who show up when things are hard.
Why High Achievers Get This Wrong
For the high-achieving, high-responsibility people we work with at A3, social connection is often the first thing to go when demands increase. Work expands to fill available time. Family obligations take whatever's left. And friendships—the relationships that require active maintenance but don't have built-in forcing functions—quietly atrophy.
The logic feels sound in the moment: "I'll reconnect once this project is done, once things settle down, once I have more bandwidth." But things never settle down. And the costs of social disconnection compound silently, in exactly the same way as chronic stress.
Here's the reframe: social connection isn't a reward for finishing your work. It's not leisure. It's a stress intervention, one of the most powerful ones available.
Practical Implications
This isn't a section where we can give you a protocol. There's no "11 minutes per week" minimum effective dose for friendship, regular NY Times articles to the contrary. But there are some principles worth considering:
Prioritize consistency over intensity. Brief, regular contact with close friends is more protective than occasional epic gatherings. A weekly call, a recurring dinner, a standing weekend walk. These rhythms compound over time in ways that sporadic reunion trips don't.
Protect the time proactively. If social connection matters (and the research says it should), it needs to go on the calendar with the same priority as workouts or work meetings. Not "if there's time," but scheduled and defended.
Audit your social environment. Not all relationships are restorative. Some are obligations; some are actively draining. You don't need to cut people out dramatically, but it's worth being honest about which relationships leave you feeling better versus worse, and allocating your limited time accordingly.
Consider the people you live and work with. These are your highest-dose social exposures. A supportive partner, a collaborative team, a household that feels calm rather than chaotic. These aren't just "nice to have." They're the environmental factors that shape your stress physiology daily.
The One Thing You Can't Hack
Throughout this series, we've covered interventions you can stack, optimize, and systematize. Breathing protocols, training programs, temperature exposure, supplements. Many of them can be done solo. That's part of their appeal for self-reliant high achievers.
Social connection is different. It can't be optimized in isolation. It requires vulnerability, reciprocity, and time—things that don't fit neatly into a productivity framework.
Nonetheless, of all the interventions in this series, it might be the one that matters most. Not because the effect sizes are largest in any single study, but because the absence of connection corrodes everything else. Sleep suffers. Resilience drops. The other tools in your stack become less effective when you're running on empty socially.
The people around you are part of your environment. Choose them with care. Invest in them consistently. And don't let the urgent crowd out the essential.
Things to Try Today
We've covered a lot of ground, from ice baths to lavender diffusers to the people you spend time with. Here's how to actually start:
If you're new to cold exposure: Start with cold showers. Finish your normal shower with 30-60 seconds of the coldest water you can tolerate. That's enough to begin building the habit and (based on the Dutch RCT) enough to produce measurable benefits. Work up from there if you want more.
If you have sauna access: Use it more frequently. The benefits accumulate at 3-4+ sessions per week, and evening sessions 1-2 hours before bed can double as a sleep intervention. If you don't have access, don't stress; this one's a bonus, not a requirement.
For an immediate air quality win: Open a window. Seriously. If you work from home or have any control over your space, better ventilation is the lowest-friction fix for cognitive fog. If you want to get precise about it, a CO2 monitor ($100-200) is one of the highest-ROI purchases in this entire stack.
To fix your light environment: Maximize natural light during the day (sit near windows, take outdoor breaks), and dim your space in the evening (prioritizing floor lamps instead of overhead lights). Screens off or dimmed in the 1-2 hours before bed. Night mode helps marginally; actually reducing light levels helps more.
If you're skeptical about aromatherapy: Try it anyway. A lavender diffuser costs $30-50, the effect sizes in the research are legitimately large, and the downside is... your room smells nice. Run it while winding down before sleep and see what you notice.
For your social environment: When did you last have unhurried time with a close friend? Not a work event, not a family obligation, but actual connection with someone who knows you. If you can't remember, that's data. Put something on the calendar this week, even if it's just a 30-minute call. Protect it like you would a workout.
The non-negotiable minimum: Be intentional about at least one environmental factor. Temperature, air quality, light, space, or people. Pick the one where you're currently most exposed to chronic low-grade stress, and make one change. Environment is cumulative; small fixes compound.
What's Next
Environment is the invisible hand shaping your stress physiology. Most people ignore it entirely, which means most people are leaving easy gains on the table.
But there's still one major category we haven't addressed: what you put in your body.
Next up: Nutrition, Supplements, and Adaptogens—from the basics (blood sugar, caffeine) to the things worth considering (ashwagandha, magnesium, creatine, etc.) to the melatonin dosing most people get wrong.
The interventions in this post work for most people—but "most people" isn't the same as you specifically. At A3, we combine biomarker data, genetic insights, and ongoing coaching to help clients figure out exactly which protocols will move the needle for their particular physiology and goals. If you want help building a personalized stack rather than experimenting on your own, we're here to help.