What should you look for on the bottle?
Look for three separate details: broad spectrum protection, SPF 30 or higher, and a stated water resistance duration. Broad spectrum covers ultraviolet A and ultraviolet B, usually shortened to UVA and UVB. UVA contributes to early skin aging; UVB is the main cause of sunburn. Both can contribute to skin cancer.13
A bottle can say "sport" without meeting a special FDA definition for that word, so the front label is not a coaching qualification. Check the actual water resistance statement instead. On US labels, the tested duration is either 40 or 80 minutes.34
SPF 30 filters out about 97% of UVB rays. Higher SPF filters slightly more, but no sunscreen filters out all UVB rays. A higher number does not extend the time between applications. SPF and water resistance answer different questions, even when the packaging makes them look like one very impressive number.13
Is 40 or 80 minute water resistance better?
| Label | What it means | When to choose it |
|---|---|---|
| Water resistant for 40 minutes | Remains effective for 40 minutes while swimming or sweating. | Shorter sessions, with reapplication at the labeled interval. |
| Water resistant for 80 minutes | Remains effective for 80 minutes while swimming or sweating. | Longer sweaty sessions or swimming, with fewer scheduled applications than a 40 minute formula. |
| No water resistance | Not the appropriate choice for swimming or sweating. | Choose a water resistant sunscreen instead for these activities. |
No sunscreen is waterproof or sweatproof: every sunscreen eventually washes off. Follow the bottle's swimming and sweating directions, and reapply after toweling off. When outdoors without swimming or sweating, reapply at least every two hours. An 80 minute label is not permission to finish an entire long event without another application.23
Which format should you choose?
| Format | Useful for | Application detail |
|---|---|---|
| Cream | Dry skin and the face. | Cover exposed skin generously. |
| Gel | Oily complexions and hairy areas. | Useful for exposed scalp or chest areas. |
| Stick | The area around the eyes. | Keep sunscreen out of the eyes themselves. |
| Spray | People who prefer spray application. | Spray until skin glistens, then rub in for even coverage. |
The best format is one you will use repeatedly, which makes an abandoned bottle a poor piece of sports equipment. With sprays, judging whether you have applied enough is difficult. Do not spray near the face or mouth, into the wind, or near heat or an open flame.1
How to apply sunscreen before training
- 1Apply sunscreen generously and evenly to dry skin 15 minutes before going outdoors. Cover all skin exposed to the sun.
- 2Use about 1 ounce to cover an adult's exposed skin, with more needed depending on body size. For the face, use at least 1 teaspoon.
- 3Cover easily missed areas, including the ears, neck, tops of the feet and exposed scalp. Use a lip balm or lipstick with SPF 30 or higher.
- 4Read the bottle's reapplication directions before starting. Reapply at the stated swimming or sweating interval, after toweling off, and at least every two hours outdoors.
Use sunscreen on exposed skin every day you will be outside, including cloudy days and winter training. Protection is for the session ahead, not something that takes weeks to build. Keep using other sun protection measures: sunscreen reduces sunburn risk and, with protective clothing and less sun exposure, helps reduce skin cancer and early skin aging.12
Is mineral sunscreen better for athletes?
Mineral sunscreen uses zinc oxide, titanium dioxide, or both as active ingredients. It is a good starting choice for sensitive skin. Chemical and hybrid sunscreens can also provide effective protection when they meet the same SPF, broad spectrum and water resistance requirements. Choose by those requirements and your skin's tolerance, not by assuming one category is automatically better for sport.3
Effects on sweating remain uncertain across different formulas. In a small trial involving 20 active adults cycling in the heat, one sunscreen reduced local sweat production on the back, while another did not differ from untreated skin. The two tested formulas behaved differently despite both being water resistant SPF 50 sunscreens. The ingredient responsible was not identified. That finding concerns those particular formulas, rather than making mineral or chemical sunscreen a universal winner for exercise.5
If sun related dark spots are a concern, particularly with darker skin tones, consider a tinted sunscreen containing iron oxide. It adds protection against visible light, which contributes to skin darkening. For exercise, the tinted formula still needs broad spectrum SPF 30 or higher and water resistance.3
When should you stop using a sunscreen?
Do not apply sunscreen to damaged or broken skin. Keep sunscreen out of your eyes, and rinse with water if it gets into them. Stop using the product and ask a doctor if a rash occurs. Choosing a stick for the eye area does not change the instruction to keep sunscreen out of the eyes.4
What else matters during outdoor sport?
Limit direct sun exposure where possible, especially between 10 a.m. and 2 p.m. Use shade and clothing that covers exposed skin, with sunglasses and a protective hat when the activity allows. Clothing labeled with UPF, meaning ultraviolet protection factor, offers a useful way to choose sun protective clothing. Take extra care around water, snow and sand, which reflect damaging rays and increase sunburn risk.123
Where this answer comes from
- 1Sunscreen FAQsaad.org
- 2Questions and Answers: FDA announces new requirements for over-the-counter (OTC) sunscreen products marketed in the U.S.fda.gov
- 3How to decode a sunscreen labelaad.org
- 4Labeling and Effectiveness Testing: Sunscreen Drug Products for Over-The-Counter Human Use — Small Entity Compliance Guidefda.gov
- 5Sunscreen Use and Sweat Production in Men and Womenpmc.ncbi.nlm.nih.gov
