January in Philly: A Doctor's Guide to the Month

January in Philadelphia starts loud, with the Mummers strutting up Broad Street, and then goes quiet fast. The sun sets before 5 PM for the first half of the month, the wind comes off the Delaware with intent, and half the city signs up for something ambitious while the other half hibernates. This guide walks through the 4 things January asks of you, so the month builds something that lasts past February.

First, a kind word about the first week. The holidays leave most of us underslept, overfed, and behind on everything, and the calendar flipping over does not change that overnight. Give yourself the first week to land: normal meals, earlier nights, a walk when the sun is out. The plans below work better when they start from rest rather than from penance.

How to pick one baseline worth measuring

The standard January move is a crash diet judged by the bathroom scale, and by week 3 the scale has usually won. The scale is a rough instrument. It cannot tell water from muscle from fat, it punishes you for a salty dinner, and it says nothing about the things that determine how the next 20 years go. There is a calmer alternative: measure a baseline, and let a number that matters be the thing you work on.

The 4 numbers I would start with, and why:

• ApoB. Every cholesterol particle capable of lodging in an artery wall carries 1 ApoB protein, so this test counts the particles themselves rather than estimating the cholesterol inside them. It predicts heart attack risk better than the standard panel, and it is the number that a "normal cholesterol" result can hide. Our ApoB guide covers the full picture, and the case of the heart attack we caught 7 years early shows what finding it in time looks like.
• Fasting insulin. Blood sugar is the last thing to go wrong in metabolic disease, not the first. For years before glucose rises, the pancreas holds it in range by producing more and more insulin, and a fasting insulin level catches that compensation while there is still plenty of time to reverse it.
• A1C. This is the 3-month average of your blood sugar, read from the hemoglobin in your red blood cells. Alongside fasting insulin it tells you where you are on the metabolic timeline, and it is the number that improves, slowly and steadily, when the walking and the food changes are working.
• Lp(a), once in your life. Lipoprotein(a) is a mostly inherited particle that raises cardiovascular risk on its own, and roughly 1 in 5 people carries an elevated level without knowing it. Because it is set largely by your genes, you generally only need to measure it once. If it is high, it changes how assertively the other numbers should be managed, and it is worth knowing about your family too.

Getting a baseline is less of a production than it sounds. It is one fasting blood draw on a weekday morning, coffee after instead of before, results back in about a week, and then a conversation with someone who explains what your numbers mean for you rather than emailing a PDF of reference ranges. That last part is the whole point. A baseline you understand becomes a plan; a baseline in a portal becomes a source of 2 AM searching.

These numbers respond to the same small habits a January resolution hopes to build, but they measure the outcome you care about rather than a proxy for it. Your weight can hold steady while your ApoB drops 25% and your fasting insulin comes down by half, and that version of January is a success by every measure that predicts your future.

What Philly's dark months do to vitamin D, sleep, and mood

Philadelphia sits at about 40 degrees north latitude, and from roughly October through March the winter sun stays too low in the sky for its UVB rays to reach skin with enough strength to make vitamin D. It does not matter how sunny the day looks or how long you stand in it; the angle does the deciding. Layer on January's short days, with sunrise near 7:20 AM and sunset before 5 PM, and most Philadelphians spend the month making almost no vitamin D while also seeing very little of the bright light that keeps the body's clock on time.

Here is how to work with the season rather than against it:

• Test, or supplement sensibly, or both. A 25-hydroxyvitamin D blood level is the direct way to know where you stand, and late January is when levels bottom out. If testing is not in the cards, a daily 2,000 to 5,000 IU of vitamin D3, paired with 100 to 200 mcg of K2 in the MK-7 form and taken with a meal that contains fat, is the standard winter approach for most adults here. The pairing matters because D3 raises how much calcium you absorb and K2 helps direct that calcium into bone rather than arteries; the full logic, and who should talk to a doctor first (anyone on warfarin, among others), lives in our vitamin D3 + K2 clinical guide.
• Get morning light on your eyes, even gray light. The body's master clock sets itself by the light of the first few hours of the day, and an overcast Philadelphia morning outdoors still delivers many times more light than a bright kitchen. Spending 10 to 20 minutes outside in the morning, a walk to the far coffee shop, a SEPTA stop on foot instead of the closest one, steadies sleep timing, daytime energy, and mood more reliably than almost anything sold for the purpose. If your schedule keeps you inside until noon, a 10,000 lux light box used for 20 to 30 minutes in the first hour after waking is the studied substitute.
• Protect your sleep timing when the darkness pushes it around. Long dark evenings pull bedtimes later while the alarm stays fixed, and the debt collects as January fatigue that gets blamed on willpower. A steady wake time, morning light, and a dimmer last hour of the evening hold the line. Our sleep optimization guide walks through the full architecture.
• Know when flat energy deserves labs instead of willpower-blame. If you are dragging through January despite reasonable sleep, that pattern has a differential, not a character flaw. Thyroid function, ferritin (iron stores), B12, vitamin D, and the metabolic numbers above explain a large share of winter exhaustion, and they are all one blood draw.
• Know when low mood deserves a conversation. Some winter heaviness is the season. But if most days for 2 weeks or more bring low mood, loss of interest in things you normally enjoy, big changes in sleep or appetite, or hopeless thoughts, that is seasonal depression territory, and it responds well to treatment: light therapy, talk therapy, medication, or some combination. That deserves a conversation with a doctor or therapist this month, not a promise to tough it out until April.

How to shovel snow without scaring your heart

Every winter, the first heavy snowfall in the region is followed by a wave of heart attacks, and the physiology is specific enough to plan around. Cold air on your face clamps down blood vessels and raises blood pressure before you lift anything. The lift itself is an isometric strain, gripping and hoisting rather than rhythmic movement, which raises pressure further. And most people hold their breath as they heave, adding a pressure surge inside the chest. For a heart with hidden soft plaque in its arteries, that stack of stresses arriving together, unwarmed, at 7 AM, is the most dangerous 20 minutes of the season. Our full snow shoveling guide covers the plaque biology in depth; the short version is that the snow exposes disease that was already there.

The people this matters for most: anyone over 45 with risk factors (high blood pressure, high cholesterol, diabetes, smoking, family history), anyone who is mostly sedentary the other 51 weeks of the year, and anyone with known heart disease, who should hand the shovel to someone else without negotiating with themselves about it.

If you are shoveling, do it like this:

• Warm up indoors first. Give yourself 5 to 10 minutes of easy movement before you step out, so the effort does not land on a cold, constricted system all at once.
• Push, don't lift. Treat the shovel like a plow and move snow to the side. When you must lift, take small loads, bend at the knees, and keep breathing through the effort instead of holding it.
• Take breaks on a schedule, not by feel. Every 15 minutes, stand up straight, breathe, go inside if you are cold. Wet Philly snow is heavier than it looks, and "almost done" is when most people overdo it.
• Skip the pre-shovel cigarette, heavy breakfast, or leftover-party drink. Each one adds cardiac work or narrows vessels at the worst moment.
• Know the stop signs. Chest pressure or tightness, pain spreading to the arm, jaw, or back, breathlessness out of proportion to the work, lightheadedness, or a cold sweat mean stop immediately, get inside, and call 911 if it does not fully lift within a few minutes of rest. Discomfort that improves with rest still deserves a call to your doctor that day.

The same cold that makes shoveling risky makes January a month to look sideways at your block. When the forecast calls for freezing precipitation or a wind chill of 20 degrees or below, the city declares a Code Blue, and warming centers open in recreation centers and Free Library branches, free and open to anyone, including neighbors who lost heat at home. If you pass someone sleeping outside on one of those nights, the Homeless Outreach Hotline at 215-232-1984 sends a trained team to check on them, and 911 is the right call if the person cannot be woken. The numbers, the utility help, and the rest of the city's winter safety net live in our Philadelphia city health resources guide. An older neighbor shoveling their own walk, or a rowhome with a dark window and no smoke from the vent on a Code Blue night, is worth a knock on the door.

How to keep one habit through a cold month

January is a hard month to start a habit and a wonderful month to keep a small one, and the difference is size. The research on habit formation shows automaticity builds over about 2 months of repetition, not 2 weeks, and that missing a single day does little damage as long as the next day picks the thread back up. A cold, dark month will interrupt any plan; the plans that survive are the ones small enough to restart without ceremony.

What that looks like in practice:

• Start smaller than feels impressive. A 10-minute walk after lunch, 1 set of pushups while the coffee brews, vegetables at dinner 5 nights a week. The goal in January is not the workout you would describe at a party; it is the repetition your February self inherits without effort. You can grow a habit that exists; you cannot grow one that collapsed in week 2 because it asked too much of the darkest month of the year.
• Attach it to something that already happens. After the morning coffee, after the school drop-off, when you get off SEPTA a stop early. Habits anchored to existing routines survive weather and mood far better than habits anchored to willpower.
• Give it an indoor answer before you need it. Philadelphia in January will hand you sleet, single digits, and sidewalks like a skating rink, so decide now what the bad-weather version is: stairs in the rowhome, a rec center gym or pool, a mall walked at a purposeful pace, a rowing machine, a follow-along video in the living room. The repetition counts the same indoors.
• Let the morning light walk do double duty. The 10 to 20 minutes outside that steadies your clock and mood also counts as the movement habit. On the days the Wissahickon or the Schuylkill Banks are clear, that walk gets to be the good part of the day rather than a chore.
• Judge the month by the trend, not the streak. Twenty days out of 31 is a habit taking root. If a missed day turns into a missed week, that is information about the plan's size, and the answer is to shrink it, not to abandon it.

Guidance from the clinic

"The January pattern I see most is a good person who picked an enormous plan on December 31, ran on willpower for 2 weeks, and arrived in my office in February feeling like they failed. Usually nothing failed except the plan's size. When we get a baseline instead, ApoB, fasting insulin, A1C, the whole conversation changes, because now there is a number that responds to small steady things, and small steady things are what a Philadelphia January will let you keep. I would rather see your fasting insulin drop over a year than watch any scale for a month."

Scientific References

1. Franklin, B. A., Hogan, P., Bonzheim, K., et al. (1995). Cardiac demands of heavy snow shoveling. JAMA, 273(11), 880-882.
2. Holick, M. F. (2007). Vitamin D deficiency. New England Journal of Medicine, 357(3), 266-281.
3. Golden, R. N., Gaynes, B. N., Ekstrom, R. D., et al. (2005). The efficacy of light therapy in the treatment of mood disorders: a review and meta-analysis of the evidence. American Journal of Psychiatry, 162(4), 656-662.
4. Sniderman, A. D., Thanassoulis, G., Glavinovic, T., et al. (2019). Apolipoprotein B particles and cardiovascular disease: a narrative review. JAMA Cardiology, 4(12), 1287-1295.
5. Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W., & Wardle, J. (2010). How are habits formed: modelling habit formation in the real world. European Journal of Social Psychology, 40(6), 998-1009.

Related at Fishtown Medicine

• Snow shoveling and heart attack risk - the plaque biology behind winter's most dangerous chore
• Vitamin D3 + K2 clinical guide - dosing, the K2 pairing, and who should ask first
• The heart attack we caught 7 years early - what a baseline can find while there is still time
• ApoB and heart health - the particle count your standard panel skips
• Sleep optimization - the full architecture behind steady winter sleep
• Philadelphia city health resources - Code Blue, warming centers, utility help, and who to call