Every sunscreen has a sun protection factor, or SPF, which is a measure of its strength or effectiveness. Each of us needs a different SPF, depending on whether, and to what degree, our skin burns or tans. A tan is the direct result of melanin, a brown pigment found in the epidermis that is produced when skin is exposed to sunlight.
Melanin protects the skin by absorbing, reflecting and scattering ultraviolet radiation before it penetrates the dermis, or underlying skin. However, armor that it is, melanin can’t prevent all the negative effects of the sun, and is often representative of damage. That’s why we need to use sunscreens. To determine what SPF your skin requires, you must know how long it takes your skin to burn when unprotected and exposed to sunlight. As a rule of thumb, anyone whose skin burns, whether or not it turns into a tan, should use an SPF of 15. Check with your doctor or pharmacist if you are taking antibiotics, antidepressants or antidiuretics. Some of these medications increase your skin’s sensitivity to sunlight and may decrease the time it takes your skin to burn.
Creating a Barrier
When exercising outdoors on a hot, sunny day, light-weight, light-colored clothing combined with plenty of sunscreen on both exposed and unexposed skin is the way to go. However, if overheating isn’t a concern, dark-colored, tightly woven clothing is more effective at blocking UV rays than say, a white T-shirt, which allows UV rays to reach the skin. Another barrier against sun damage comes in the form of eyewear. Protect not only your eyes, but also the skin around them, by wearing sunglasses that block 90 to 100% of the sun’s UV rays.
And, last but not least, wear a hat. Though a cap may be more comfortable for jogging, try a wide-brimmed hat that will shade your neck and face while gardening or walking outside.
Start With the Inside
Now that you know how to protect the skin’s surface, it’s time to start thinking about what you can do to make it glow from the inside out. You’re already off to a good start with exercise, which gets the blood circulating and delivers fresh oxygen to the skin all over your body. The next step is to drink plenty of water. Outdoor exercise, especially in the summer, increases your risk of dehydration. This is one risk you don’t want to take since it not only affects your performance and robs your skin of its vitality, but may be potentially hazardous to your health. Be sure to drink fluids before, during and after activity. To replenish your fluids after any outdoor activity, weigh yourself before you participate and then again after your workout. Any weight you lost is water and should be replaced by drinking two glasses (16 ounces) of water for every pound you have lost.
Everyone Needs a Little Sunlight
It’s been shown that a lack of sunlight can cause depression. After all, most plants won’t even grow without sunshine. And when the sun comes around and makes the days longer, our first instinct is to peel off our sweaters and bask in it. Go ahead. Just take precautions so you won’t have to deal with the unpleasant (and unnecessary) consequences.
- Wear sunscreen every day if you will be outside for more than 20 minutes, even when it’s cloudy.
- Sunscreen should be applied 15 to
- 30 minutes before going outdoors and reapplied every two hours or after swimming or sweating.
- Don’t skimp: One ounce—enough to fill a shot glass—is considered the amount needed to properly cover exposed skin.
- Limit your exposure to sunlight from 10 a.m. to 4 p.m. during Daylight Savings Time (9 a.m. to 3 p.m. during Standard Time), which is when the sun’s rays are the strongest and most harmful.
- When choosing a sunscreen, look for one with an SPF of 15 or higher that provides broad-spectrum coverage against all ultraviolet light wavelengths.
- Throw out old bottles of sunscreen, which can lose strength after three years.
Source: American Academy of Dermatology
What SPF Do You Need?
Follow these steps to calculate what SPF you should look for in a sunscreen:
1. Determine how many minutes your bare skin can be exposed to the sun before it burns.
2. Divide that number of minutes into the total number of minutes you want to remain in the sun.
3. The result is the SPF you should look for in a sunscreen.
For example, if your unprotected skin burns in 10 minutes, and you plan on being in the sun for three hours, you would need a sunscreen with an SPF of at least 18 (180 minutes divided by 10 minutes).
U.S. Food and Drug Administration