Moved from Chicago to Austin two years ago. Pixel was in the passenger seat, both of us confused by the 105-degree welcome. Everyone warned me about the heat (they were right), the traffic (they were right), and the allergies (oh my god, cedar fever is real). Nobody warned me about my resting heart rate. I have been wearing a basic fitness tracker for years — nothing fancy, just a 60-dollar refurbished Garmin Vivosmart that tracks RHR, steps, and sleep. When I pulled up my historical data last week to prepare for this post, I saw something strange that I had never noticed before.
Twelve months pre-move in Chicago, all seasons, my average RHR was 68 bpm with a range of 64-72. The first 6 months in Austin, my average RHR was 74 bpm with a range of 70-78. Months 6-12 in Austin, my average RHR was 71 bpm with a range of 67-75. Now in year two, fully adapted, my average RHR is 66 bpm with a range of 62-70. That is a 6-beat increase after moving, then a slow drop below baseline by month 18. What the hell happened? I dug into the physiology literature first. A 2019 study in Temperature — yes, that is a real peer-reviewed journal, I was surprised too — exposed 20 healthy adults to 30 degrees Celsius versus 23 degrees Celsius for one week in a controlled environmental chamber. At the higher temperature, resting heart rate increased by an average of 8 bpm due to peripheral vasodilation — your heart works harder to pump blood to the skin for cooling. The effect was largest in the first 3 days and persisted throughout the week.
Austin's average summer high is 35 degrees Celsius, and it stays above 30 degrees from May through September. My first summer here, I ran my AC at 74 degrees instead of Chicago's 68 degrees to save money — electricity rates are higher here. That alone could explain the initial RHR jump. But why did RHR eventually drop below baseline? That took more data. I pulled my step counts from Garmin Connect and discovered something interesting: I walk way more in Austin than I did in Chicago. Chicago winter averaged 4,200 steps per day — it is freezing, you hide inside. Chicago summer averaged 7,800 steps — pleasant, but still car-centric. Austin winter averaged 8,900 steps — mild, sunny, actually want to be outside. Austin summer, early morning or evening, averaged 6,500 steps — too hot, but still more than Chicago winter.
The mild winters and year-round outdoor access — Zilker Park, Barton Springs Pool, the Boardwalk at Lady Bird Lake, the Southern Walnut Creek Trail — mean I am moving more even when I am not trying. That increased baseline activity, over time, drives cardiovascular adaptations that lower RHR. A 2021 meta-analysis in the European Heart Journal pooled 45 studies and found that every additional 2,000 steps per day above a baseline of 5,000 was associated with a 1.2 bpm lower resting heart rate after 6 months, independent of other exercise. My step increase from Chicago winter at 4,200 to Austin winter at 8,900 is 4,700 steps, which predicts about a 2.8 bpm drop. Combined with the heat adaptation (which takes 6-12 months), that gets me from 68 to 66.
Here is the weird part — my calorie needs changed without my weight changing significantly. I tracked my intake for two weeks in Chicago (pre-move, using MyFitnessPal, same logging rigor) and two weeks in Austin (year two, same method). Same body weight at 172 pounds at both times, measured on the same scale which I shipped with me. But maintenance calories went from 2,450 in Chicago to 2,650 in Austin. That is an extra 200 calories per day — basically a Torchy's taco or a scoop of Amy's ice cream or a couple of craft beers at Zilker Brewing.
Where does that 200-calorie increase come from? Two sources. First, the increased baseline activity (steps) accounts for about 80-100 calories per day, based on standard metabolic equations. Second, the thermic effect of living in a hot climate. Your body burns calories to cool itself — sweating, increasing cardiac output, maintaining thermal homeostasis. A 2020 study in the Journal of Clinical Endocrinology and Metabolism put people in a 35-degree room for 60 minutes and measured metabolic rate via indirect calorimetry. It increased by 12% compared to 23 degrees, purely from thermoregulatory costs. Over a full day, that could add 150-200 calories. So my 200-calorie bump is plausible. The heat is making me leaner, or at least requiring me to eat more to maintain.
What does this mean for your tracking if you are moving to Austin — or any hot, walkable city? Do not panic if your RHR jumps in the first summer. Give it six months. Your cardiovascular system adapts through increased plasma volume (blood volume expands to help with cooling, which initially raises RHR but then normalizes) and improved heat dissipation. A 2024 paper in Medicine and Science in Sports and Exercise followed 45 people who relocated from cool climates to hot climates. Their RHR increased 6-10 bpm in month one, then returned to baseline by month four. By month 12, 60% of participants had RHR lower than pre-move because of increased incidental activity (they walked more in their new environment).
Also, adjust your calorie expectations. If you are from a colder place and you move to Austin, you might need to eat more to maintain your weight — or you might lose weight without trying. I gained 3 pounds in my first year (not a lot), but that was because I was eating like I was still in Chicago and not accounting for the activity bump. The calorie needs calculator on my site has a climate adjustment toggle now. It is crude — just adds 5-10% for hot climates — but better than nothing. And better than wondering why you are losing weight while eating the same amount of food.
The takeaway from my two years of RHR data is not "move to Austin." It is that your body's data will lie to you if you do not account for context. A high BMI reading during a heat wave? Could be water retention from sweating (your body holds onto fluid to help with cooling). A high RHR your first month in a new city? Could be your cardiovascular system working overtime to adapt. A sudden drop in calorie needs in winter? That is real — seasonal differences in non-exercise activity thermogenesis are documented in a 2023 Obesity paper. Always ask: what is the confounding variable here? Because there is almost always one.
I have got the full 24-month RHR graph pinned on my fridge. It looks like a roller coaster that starts high, dips, goes up again during last summer's heat wave (July 2025 — remember that one? 108 degrees for four days), and ends slightly lower than it started. If you are tracking your own RHR and see weird seasonal swings, ping me through the contact form on bmitool.org. I will send you the spreadsheet template that separates weather effects from fitness effects. It has got conditional formatting and a moving average column. Because of course it does. I am a data analyst. What did you expect?
Has your resting heart rate changed since you moved? Or since the seasons changed? What is your body trying to tell you that the watch does not explain?
Peripheral vasodilation in heat raises resting heart rate 6-10 bpm initially. A 2019 study in Temperature found this effect persists for about a week in controlled conditions. Austin's 5-month summer means your cardiovascular system works harder year-round.
RHR typically returns to baseline by month 4-6. By month 12-18, many people have lower RHR than before due to increased incidental activity — Austin's mild winters enable year-round outdoor movement.
Yes. Thermoregulatory costs add 150-200 calories daily in summer. My maintenance went from 2,450 in Chicago to 2,650 in Austin. The Calorie Needs Calculator on this site includes a climate adjustment for this reason.
