You've heard the rules. Slow down in no-wake zones to avoid accidents with boaters or swimmers. Wear PFDs to prevent chance overboard spills from becoming something worse. Put on sunscreen so you won't get that itchy, irritating red glow. And drink lots of water.

It all sounds like harping from an overprotective parent, but in truth, it's information that will make your family's boating experience a lot more enjoyable. Out of those basic rules, the two easiest to neglect – protection from sunburn and dehydration – may be the most dangerous. Severe dehydration can lead to serious health complications. Sunburn can lead to skin cancer, and according to the American Academy of Dermatology (AAD), one in five Americans will develop skin cancer in his or her lifetime, while 1 million will be diagnosed with skin cancer this year alone. There's a reason for heeding all that advice doctors and dermatologists shout at the top of their lungs come summertime. And since you're in charge of your kids' well-being, it's imperative you know the "whys" and "hows" of keeping them safe during hot-weather boating.

Part of the allure of a day on the water is spending time in the sun. And undoubtedly, you've had your primary care physician and dermatologist remind you to wear sunscreen. For some, these warnings go in one ear and out the other, in part because many people lack an understanding of exactly what happens to your skin when it's exposed to the sun.

"Ultraviolet light from the sun is a form of radiation, and when too much of that radiation hits your skin, it actually damages the genetic material in your skin cells causing mutations in your DNA," said Jack Resneck Jr., M.D., an assistant professor of dermatology and health policy at the University of California, San Francisco School of Medicine.

"Some of those damaged cells die right away, leading to the redness and soreness we see as a burn. Other damaged cells survive, and if they get enough sun exposure and enough damage to their DNA, then they can start to grow out of control and form cancer."

It's particularly important for children to avoid overexposure. Resneck said some studies have suggested that a significant portion of many people's lifetime exposure to ultraviolet radiation from the sun occurs by the age of 18, and multiple blistering sunburns during childhood have been linked to increases in skin cancer later in life. "It often takes multiple exposures to sun to create a cancer, so starting with lots of sunburns in childhood certainly starts things off on the wrong foot," he said.

Going to a tanning salon is a surefire way to earn a scowl from your dermatologist, but being outside in general – and on the water – poses its own set of challenges to maintaining healthy skin. Boating exposes you to what Resneck calls a "double dose" of sunlight, which means sunlight hits you directly and reflects off the water. Surfaces such as sand will also reflect UV rays and, in the wintertime, snow.

There are also increased risk factors involved inside your body. If you're taking medication, you may want to monitor your exposure to the sun more closely. Certain antibiotics (such as doxycycline and ciprofloxacin), nonsteroidal anti-inflammatory drugs (such as ibuprofen) and diuretics (such as furosemide or hydrochlorothiazide) can increase the chance of sunburn, Resneck said.

"When you take an oral medication, depending on the medication, some of that drug ends up being carried by your bloodstream to the skin," he said. "Certain drugs are then ‘activated' by sunlight. They undergo a chemical change when exposed to ultraviolet radiation, and the resulting chemical damages skin cells.  Most people who have one of these ‘phototoxic' reactions simply notice an exaggerated response to sun exposure. In other words, they sunburn more easily."

 

If you're going to be exposed to the sun for a prolonged period of time, the obvious advice is to lather up with sunscreen. What number and type of sunscreen should you get? Sunscreens are rated by the Sun Protection Factor (SPF). A higher SPF number means greater protection, but not necessarily in a proportionate amount.

For instance, an SPF rating of 30 is not twice as strong as an SPF rating of 15. The AAD says that an SPF of 30 screens 97 percent of UVB rays, while an SPF of 15 screens 93 percent of UVB. According to the AAD, dermatologists strongly recommend using a broad-spectrum (UVA and UVB protection) sunscreen with an SPF of 15 or greater year-round for all skin types. Keep in mind, though, that no sunscreen will protect you 100 percent from UV rays, and the best type of sunscreen for boating should be the water-resistant kind.

Although sunscreen is one of the biggest steps you can take toward UV protection, there are plenty of additional measures to consider. Ample shade with Bimini tops, as well as protective clothing such as long-sleeved shirts and pants, go a long way toward reducing the chance of unpleasant visits to the dermatologist. Use any restroom breaks or pit stops back at the dock as a time to reapply sunscreen.

Too Much or Too Little?

The sun is not just zapping you and your kids with radiation; it's also sapping you of energy and fluids. While you've heard of the negative consequences of becoming dehydrated (vomiting, dizziness, nausea), in rare cases there can be even bigger health ramifications.

So, how much water do you need? Surprisingly, overhydrating can have its own negative effects. Drinking way too much water isn't the answer to avoiding dehydration. Sodium and potassium levels will be diluted, and you may suffer hyponatremia (low level of sodium) or other unpleasantries.

What's the best way to achieve a healthy balance? Moderation. The standard mantra for water intake is eight glasses a day. According to the Ohio Boating & License Safety Course, "A good rule of thumb while you're out in the water is to drink at least 1 quart of water per hour."

Don't play catch-up if you can avoid it. Drink plenty of fluids before heading on board, and have your children do the same.

What probably sounded like harping as a little kid is actually sage advice. Think of the extra water on board and heavy-duty sunscreen like you do PFDs – standard protocol for a day of boating. Then explain to your kids why these precautions are important. Hot weather may not seem as dangerous as an oncoming boat or overboard accident, but you should take the potential hazards just as seriously.