Yes but with some effects. Repellents are designed to create a vapor barrier above the skin. Good sunscreens are designed to work below the skin. Wearing both usually compromises both functions especially when sprays are used. A Controlled Release Insect Repellent lotion is the most compatible topical repellent for a sunscreen.
Our recommendation is that if you need both types of protection, first apply Stay-Put® by Sawyer a bonding base sunscreen. After 10 minutes, apply Sawyer Controlled Release Insect Repellent Lotion or a composite repellent lotion. The bonded sunscreen is less susceptible to the solvents contained in the repellent, including sprays if you use them. The Sawyer Controlled Release Insect Repellent Lotion or a composite repellent in lotion form is more compatible with the sunscreen than a spray and requires less reapplication for maximum protection of both needs.
If properly applied (1 1/4 ounce per full body coverage) you seldom need more than an SPF 15. See the paragraph below for when you may need more. However, most people put on only half of the recommended FDA standard. An SPF 15 applied at half rate is effectively an SPF 7, better than nothing but still not a true sunscreen. If you can discipline yourself to put on a generous amount, then after it has fully absorbed into the skin, you will benefit by having less chemicals in the skin which allows your skin to breathe easier. If you just can’t bring yourself to lather it on then jump to an SPF 30 which, when half applied, still leaves you with an effective protection of an SPF 15. If you’re sensitive to oxybensone or benzephenone then stick with the SPF 15 which generally does not include that sunscreen.
In planning a trip, use the 1 1/4 ounce per person per day figure as a guideline. If you’re building a tan, or reducing your skin exposure via clothing, then reduce your anticipated need accordingly. Keep in mind that a soaked cotton shirt yields protection equivalent to only an SPF of 4 to 8 only and therefore you may need to wear a sunscreen below the shirt if exposed to water or sweat.
They can, in two ways. Residual sunscreen on the skin can affect your grip and it can reduce your ability to sweat, which is your body’s mechanism to transfer heat created by your exertion. By not losing adequate heat, your internal body temperature rises, which saps your energy levels and causes many organs to focus on heat management functions rather than normal support functions. The newer sunscreen formulations work below the skin and allow the skin to breathe and sweat much more efficiently, thereby leaving you with more energy to perform your athletic activity.
Above the skin sunscreen needs to be re-applied much more frequently than below the skin sunscreens, but replacement of each depends on several environmental factors and also the quality of the sunscreen. Keep in mind the following factors which affect sunscreen effectiveness:
Type of Sunscreen: Film, Wax or Bonding Base
Time of Day: Peak Sun is 10:00 a.m. to 3:00 p.m.
Time of Year: Peak Sun is May though July
Pre-Tanning of the Skin: Your skin is more susceptible in the spring and early summer than it is after you have some level of tan base.
Areas of Thin Skin: Nose, Ears, Forehead, Top of Head, Top of Feet, and Shoulders need extra Sunscreen and attention because they have less layers of skin to protect themselves.
High Altitudes: Above 6,000 feet significantly increases your exposure to sunrays.
Higher Altitudes: Above 10,000 feet offers very little natural protection at any time of the year.
Low Latitudes: The closer you are to the equator the greater your ray intensity. People in Northern climates vacationing in Southern climates are particularly vulnerable.
Exposure to much Rubbing or Flushing: Frequent towel drying or water skiing removes Sunscreen at a much faster pace than other activities.
Profuse Sweating: May cause Sunscreen, especially above the skin Sunscreen, to migrate.
Use with Insect Repellents: May cause the loss of up to 30% of the SPF protection level.
If your environment includes several of the above, you may need to consider using a higher SPF level or more closely monitor your skin, especially the areas of thinner skin. If your environment includes more than several of the above, then you really need to watch your skin closely and take other precautions as well, such as more sun protecting clothing, hats, and staying out of the sun at peak times.
All sunscreens will burn your eyes if the lotion is rubbed into the eye area during application. Once applied to cool dry skin the better sunscreens, such as a bonding base formula, will not migrate — that is, run down into the eyes from the forehead while sweating or in the water. Older formulas which were designed to work above the skin may still migrate when exposed to water or sweat.
Generally, three to four years. Exposure to extreme low or high temperatures can shorten its life. In general, if it still looks creamy white, it’s probably still good.