My Sun-Safety Tips for the Dog Days of Summer

My Sun-Safety Tips for the Dog Days of Summer

We're in the dog days of summer...

In other words, here in the Northern Hemisphere at least, it's the hottest time of the season.

The term has nothing to do with man's best friend panting in the heat, if that's what you're thinking of.

Turns out, the term "dog days of summer" came from the ancient belief that the scorching heat was connected to the "dog star" Sirius rising up with the sun.

But with the sweltering temperatures, it's a good time to remember that July is Ultraviolet ("UV") Awareness Month, too.

Today, we'll talk about how to stay safe in the sun – while still soaking up just enough to keep your body's vitamin D engine humming...

Skin cancer is the most commonly diagnosed cancer, with 5 million new cases each year.

Too much sun exposure increases the likelihood of getting certain skin cancers. It also wrinkles and discolors the skin, making us look older.

But remember... some sun exposure is vital to good health.

Vitamin D produced by the body from UVB rays in sunlight is critical in preventing diseases such as multiple sclerosis and depression. So you don't have to be terrified of catching some rays. A little bit can do wonders to boost vitamin D levels – without causing inflammation or damaging your skin. That's according to a Nature Scientific Reports study published earlier this month...

In the small, randomized clinical trial, 24 healthy adults were exposed to short bursts (or four five-minute-long sessions) of UVA and UVB rays, with blood samples taken three times: before, halfway through, and after the four exposures.

Researchers found that vitamin D levels significantly increased by the end of the study. While signs of oxidative stress increased slightly, levels of inflammation markers (like C-reactive protein) stayed relatively stable, along with levels of antioxidants. Nor was there any sign of external skin irritation. And interestingly, body-fat percentage dropped significantly, meaning an improved body composition, while the metabolic rate increased a bit.

Now, don't think of this as an excuse to bake in the sun – the experiment, after all, was done under carefully controlled UV exposures with just a small group of folks.

Skin cancer is still a big threat. Here's how to strike a sensible balance between getting enough vitamin D without raising your skin cancer risk...

My Tips to Stay Safe in the Sun

1. Know your skin type.

An important first step to protecting your skin from too much sun is to figure out your skin type. The best method is to use a simple guide called the Fitzpatrick skin type system. The questionnaire breaks down into genetic components (your eye color, hair color, etc.) and reactivity (how quickly you burn). By adding up the points you receive, you then determine your skin type. It ranges from Type I (you always burn) to Type VI (you never burn).

Your skin type helps determine how long you can be in the sun until you start to burn. The lighter you are, the more quickly you will burn. You can figure out your type right here.

But if you're typified as an easy burner, that doesn't mean you have to ladle on the sunblock...

You can manage your exposure by covering your skin and minimizing time outside when the sun is strongest.

For example, if you have Type I or Type II skin, going outside without sunblock and with arms and legs exposed for about 10 minutes is enough to produce all the vitamin D you need. You can calculate it more in depth with something called the UV index...

2. Know the UV index.

A good way to measure sun exposure is to look at the UV index. It tells you how strong UV radiation is during the day, on a scale from 1 to 11. You can search by ZIP code here on the U.S. Environmental Protection Agency website. For days when it's very high (that is, an index value of 8 or higher), staying inside or under the shade is a safer option, particularly for seniors and those who burn quickly.

You can use the UV index to calculate the standard erythemal dose ("SED"). This is the amount of sun needed to produce enough vitamin D. Keep in mind, though, that your needed dose may vary due to personal factors like genetics, skin pigmentation, and your location.

To calculate a single unit, take your local UV index level and divide 60 minutes by that number. As of this writing, the UV index in Baltimore is 8. That means one SED is seven and a half minutes.

Then, find your skin type and figure out how much time you need to spend without sunscreen. If you're "very fair" or a Type I or II on the Fitzpatrick scale, that means you need one to two SEDs, or about seven to 14 minutes.

3. Don't waste money on high SPFs.

Sunscreens with SPF 8 block 87% of UVB rays (the ones that burn your skin). SPF 15 sunscreens filter out about 93%. But from there, the protection levels aren't so different from the lower SPFs... SPF 30 blocks 97%, and SPF 100 blocks 99%.

Keep in mind that the higher the number, the more risk you're taking with chemicals that can cause irritation or trigger an allergic reaction. Many sunscreens also contain oxybenzone, which animal studies have shown to be an endocrine disruptor. Not to mention, it's very harmful to marine life.

So you are slathering on more chemicals for only marginally better protection if you use SPF 100 versus SPF 30. Not to mention, the super-high numbers can offer a false sense of security where you might skimp on the amount or fail to reapply.

And despite that high SPF, you're still not protected against UVA rays, which reach deeper levels of skin and increase your risk of developing certain types of skin cancer.

And if your concern is skin cancer, make sure your sunscreen protects against UVA rays. UVA rays damage our DNA because they penetrate deeper. These are the ones that also cause you to tan. If you want to protect yourself, look for a broad-spectrum, mineral-based sunscreen (one that protects against UVA and UVB).

But you don't have to slather on sunscreen to protect your skin...

Don't forget there's the option of protective clothing that you can easily shuck off or slip on without having to deal with slimy, goopy sunscreen lotion or a choking haze of spray-on sunscreen. (Just remember to apply the stuff to exposed areas if you'll be out and about for an extended period of time.)

Ultraviolet Protection Factor ("UPF") is a measure of how well the garment blocks UV rays. Look for a UPF rating of 30 to 50. The fabric will likely be tightly woven (or thick).

Synthetics like polyester or nylon work better than the more breathable cotton. But sticking to a loose fit can help with airflow. Plus, it'll ensure that the fabric won't get overly stretched, which can mess with the UV-blocking capability.

What's more, if you do go out, then wear a hat – particularly a wide-brimmed one. That helps protect the sensitive parts of your face, ears, and neck. Invest in cover-ups, hats, and light jackets for the summer, too. Want even more protection for your noggin? Some companies like Sunday Afternoons and Fractel make hats with detachable capes that shield your ears and neck.

And coming from an eye doctor... always, always, always wear sunglasses. Over time, sun exposure promotes the development of macular degeneration or cataracts. Be sure to get ones labeled "UV400" or "100% UVA/UVB." Unsure whether you're protected? Have your optician or ophthalmologist test your pair.

Also, if you have a family history of skin cancer, take extra precautions...

That includes checking yourself for skin cancer and going every few years for a skin cancer screening. Make sure you keep an eye on any strange moles and marks.

Getting vitamin D from sunlight is the most effective way to get your daily amount. Just take the proper precautions, then go outside and enjoy yourself.

P.S. Summer is also peak travel season. And if you're planning on flying this summer, you'll want to check out my recent issue of Retirement Millionaire to stay safe in the air... not from a crash, but something far more likely to kill you, especially if you're older. Get instant access with a 30-day, risk-free trial by clicking here.

What We're Reading...

Here's to our health, wealth, and a great retirement,

Dr. David Eifrig and the Health & Wealth Bulletin Research Team
July 15, 2025