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

May is the month Philadelphia comes back outside. Broad Street fills with runners on the first Sunday, the shore houses get opened and aired out ahead of Memorial Day, and the evenings on the Schuylkill Banks stretch long enough to use. The catch is that the sun gets strong weeks before the air feels hot, which is how the first burn of the year happens in a month that never feels like summer. The 3 things worth setting up now, a look at your skin, a sunscreen you will keep using, and a strength habit, pay off for the whole season ahead.

The skin check worth doing before peak sun

Almost everyone has a spot. The mole that might be darker than it used to be, the rough patch that keeps coming back on an ear or a forearm, the mark a partner noticed on your back last summer that never got looked at. May, which is also Skin Cancer Awareness Month, is the month to deal with it, for a simple reason: Philadelphia's UV climbs into the high range by midday now, and the beach season ahead will add months of exposure on top of whatever that spot has already collected. Getting an answer before peak sun means you spend the summer protected instead of wondering.

Most of the time, a photo settles it. A clear, well-lit picture next to a coin for scale, sent through our messaging, lets me sort a spot within a day: most turn out to be the ordinary company skin keeps, seborrheic keratoses, cherry angiomas, moles behaving like moles, and the ones that need a dermatologist's eye get a priority referral instead of a 4-month routine wait. That triage is the difference between May worry and May certainty.

The changes that deserve attention follow the ABCDE pattern, and it is worth knowing all 5:

• Asymmetry: one half of the spot does not match the other.
• Border: edges that are ragged, notched, or blurred rather than smooth.
• Color: more than one shade in the same spot, or a color changing over time; black, blue, and red patches within a brown mole matter.
• Diameter: larger than about 6 millimeters, the width of a pencil eraser, though melanomas can be smaller.
• Evolving: any change in size, shape, color, height, or a spot that itches, bleeds, or will not heal. Evolution is the most important letter of the 5, and it is also the reason the "ugly duckling," the spot that looks different from all your others, earns a photo even when no single letter applies.

Not every skin cancer is a mole. A pearly bump that slowly grows, a sore that heals and reopens in the same place, and a scaly patch that keeps returning on sun-exposed skin are the patterns of basal cell and squamous cell cancers, which are far more common than melanoma and very treatable when found early.

Earlier is simpler across the board. A thin melanoma is usually cured with an office excision and a follow-up schedule; a deeper one means wider surgery, lymph node evaluation, and an oncologist. The gap between those 2 paths is often measured in months of waiting, which is why the photo is worth sending this month. And if you have fair skin that burns before it tans, many moles, a family history of melanoma, a tanning bed history, or a medication that suppresses your immune system, a baseline full-skin exam with a dermatologist is worth putting on the calendar; we coordinate that referral, keep the findings in your chart, and handle the in-between spots by photo so the dermatology visit is for what needs it.

How to pick a sunscreen you will re-apply

The best sunscreen is the one still going on your skin at 2 PM in August, which makes texture, not the number on the front, the deciding factor. A formula that feels greasy, stings your eyes, or leaves a cast you hate will get used once and abandoned by June, and an abandoned SPF 50 protects you less than an SPF 30 you like enough to use again with sandy hands. Buy by feel, and buy in May, so the tube is in the bag before the first shore weekend rather than after the first burn.

Here is how to choose, and how to use what you choose:

• Start with broad-spectrum SPF 30 to 50. "Broad-spectrum" on the label means it covers UVA (the deeper-penetrating rays that drive photoaging) along with UVB (the burning rays that drive most skin cancer risk). Below 30 gives up meaningful protection; above 50 adds very little. The full physics, including what the UV Index tiers mean for your skin type, lives in our UV Index guide.
• Mineral or chemical is a personal fit, not a ranking. Mineral filters (zinc oxide, titanium dioxide) sit on the skin, work the moment you apply them, and are the gentler choice for sensitive or reactive skin and the area around the eyes; the trade-off is a white cast, more visible on deeper skin tones, which tinted versions mostly fix. Chemical filters (avobenzone, homosalate, octisalate, and their cousins) rub in transparent and come in lighter textures that work under makeup or on a run, but they need about 15 minutes to bind before sun exposure and can sting when sweat carries them into your eyes. Both work when you use enough. The right answer is whichever one you will re-apply.
• Use the quarter-teaspoon face dose. A quarter teaspoon covers the face and ears, with roughly the same again for the neck, and a full shot glass, about an ounce, covers an adult body in a swimsuit. Most people apply a quarter to half of that, which is the most common reason sunscreen "does not work."
• Set the 2-hour clock. Re-apply every 2 hours outdoors, and after every swim or towel-off regardless of the clock. Water resistance on the label is rated in minutes, 40 or 80, and the towel removes more than the water does.
• Re-application beats a bigger number. SPF is measured in a lab at a thickness almost nobody uses in life, so the applied-once protection of any bottle sits well below its label. At proper dose, SPF 30 blocks about 97% of UVB and SPF 50 about 98%, a small gap next to the one between a single morning application and a day of re-applying. The shore adds its own math, since sand and water reflect UV up under hats and umbrellas; the full beach-day plan, UPF shirts included, is in our sun protection playbook.

Broad Street weekend and the first shore trips

The Broad Street Run lands on the first Sunday of May, 10 miles straight down Broad from North Philly to the Navy Yard, and it pulls tens of thousands of runners plus half the city out to cheer. Two health notes for that weekend. First, the course has almost no shade, so a race that starts in cool morning air finishes under strong late-morning sun; sunscreen on the face, ears, neck, and shoulders before you get in the corrals is part of the kit, along with fluids the day before, since the taper week is also the hydration week. Second, respect the week after. A 10-miler leaves microscopic muscle damage that peaks a day or 2 later, and easy movement, sleep, protein, and patience recover it better than a triumphant hard run on Tuesday.

If the race, or watching it, left you wanting a running life rather than a running day, the city makes that easy; our guide to Philly running clubs maps the groups by neighborhood, pace, and vibe. And when the first shore weekend arrives at the end of the month, remember that skin coming out of a Philadelphia winter is at its palest and most burnable of the whole year, on a beach that reflects UV up at you from sand and water. Memorial Day burns are a fixture in clinic every June, and they are the most preventable thing in this guide.

Why muscle is a longevity organ

Strength is the through-line of this month, and of most of what we do for healthspan, because muscle is not just what moves you. It is a metabolic organ, and treating it that way changes how you spend a May when motivation is already high.

Three jobs muscle does that have nothing to do with how it looks:

• Glucose disposal. Skeletal muscle is where most of the glucose from a meal ends up; under insulin's signal, muscle takes up the large majority of it and stores it as fuel. More muscle means more storage capacity, and a recently used muscle pulls in glucose even when insulin resistance has dulled the signal, which is why a walk after dinner lowers blood sugar and why strength training is one of the most powerful tools we have against the drift toward type 2 diabetes.
• Fall prevention, decades early. The fall at 75 that breaks a hip is usually set up in the 40s and 50s, when muscle and, even faster, muscle power, the ability to produce force quickly, start their slow decline. Catching yourself on a curb is a power move, and power responds to training at every age. The people who stay off the ground in their 70s are largely the ones who kept loading their legs through the decades before.
• Bone signaling. Bone remodels itself according to the forces placed on it, and the strongest routine force it feels is muscle pulling on it. Resistance training tells the skeleton, site by site, that it is still needed, which is why lifting protects the hip and spine in ways that swimming and cycling, for all their other virtues, do not.

The dose that earns most of this is 2 strength sessions a week, covering the basic patterns: a squat or sit-to-stand, a push, a pull, a hinge, and a carry. That matches the major physical activity guidelines, and it fits inside 2 half-hours. None of it requires a gym. Bodyweight squats and counter-height pushups in the kitchen, a backpack loaded with books for carries and for trips up the rowhome stairs, a set of resistance bands hanging on a door, the pull-up bars along the Schuylkill Banks; the equipment question is solved for well under the cost of a single gym month. What matters in May is putting the 2 sessions on the calendar like appointments, because the habit you hold through this month tends to survive the summer, and consistency over years, more than intensity in any single season, is what builds the version of you who feels strong at 70.

Guidance from the clinic

"The pattern I see with skin is timing. The spot someone shows me in October is usually one they first noticed in May, and the 5 months in between added nothing but worry and sun. Most of the time a photo settles it in a day, and when a spot does need a dermatologist, being early makes everything about that visit smaller and simpler. Strength works the same way. The patients who feel best at 70 are rarely the ones who trained hardest at 50; they are the ones who kept 2 easy sessions a week going through every season in between."

Scientific References

1. Green, A. C., Williams, G. M., Logan, V., & Strutton, G. M. (2011). Reduced melanoma after regular sunscreen use: randomized trial follow-up. Journal of Clinical Oncology, 29(3), 257-263.
2. Friedman, R. J., Rigel, D. S., & Kopf, A. W. (1985). Early detection of malignant melanoma: the role of physician examination and self-examination of the skin. CA: A Cancer Journal for Clinicians, 35(3), 130-151.
3. DeFronzo, R. A., & Tripathy, D. (2009). Skeletal muscle insulin resistance is the primary defect in type 2 diabetes. Diabetes Care, 32(Suppl 2), S157-S163.
4. Srikanthan, P., & Karlamangla, A. S. (2014). Muscle mass index as a predictor of longevity in older adults. American Journal of Medicine, 127(6), 547-553.
5. Bull, F. C., Al-Ansari, S. S., Biddle, S., et al. (2020). World Health Organization 2020 guidelines on physical activity and sedentary behaviour. British Journal of Sports Medicine, 54(24), 1451-1462.

Related at Fishtown Medicine

• Healthy skin aging - the evidence on sunscreen, retinoids, and glucose control for skin over time
• UV Index in Philadelphia - what the tiers mean and what to do at each one
• Sun protection for Philly and the Jersey Shore - the full beach-day plan, UPF clothing, and treating a burn
• Running clubs in Philly - finding a group by neighborhood, pace, and vibe
• Pollen in Philadelphia - for the yellow film on the car and the itchy eyes that come with it
• July in Philly - the next chapter: heat, hydration, and the shore kit