It’s summer, and you may be planning to spend a lot of time outdoors on your vacation – so, remember: it’s important to develop a base tan and schedule enough time to develop it gradually.

Moderate exposure to ultraviolet light helps the skin develop a natural barrier to protect the body from future UV exposures; it increases your tolerance to UV. Ultraviolet light stimulates the production of melanin, which then surrounds the cores of cells to protect their DNA. This melanin substance absorbs and/or scatters radiation.

In addition, UV exposure thickens the epidermis (the skin’s top layer), thereby limiting the amount of UV that could penetrate the deeper skin layers. If this photo-protection (base tan) is not developed or a sunscreen is not used, sunburn can occur and the DNA of the skin cells may be damaged. Repeated sunburns can result in damaged cells; therefore, it’s wise to use a broadband sunscreen during prolonged UV exposure or in sun-intensive regions.

Combining indoor UV exposure with too much natural sun exposure can also cause skin damage. One should always be mindful of the dangers of overexposure, as it may lead to chronic skin damage.

Without repeated UV exposure, your tan will disappear or fade over time. This is because the pigmentation (tanning) process occurs in the epidermis – the top skin layer – which replaces all its cells every 28-30 days. Skin cells contain melanin, which darkens as a result of UV exposure. Cells in the inner portion of the epidermis divide themselves, migrate to the surface, gradually die and slough off. If a person stops tanning for an extended period of time, they will probably have to start at the beginning of the process, using the minimum recommended exposure schedule for their skin type. Subsequent session times may be gradually increased, leaving at least 48 hours between exposures. This session schedule assumes, however, that no unusual reaction or sunburn occurs.

If you decide to use a spray tanning booth or self tanning product for that “immediate” tanned look, remember that these sources do not provide a natural barrier, or photo-protection, and will leave you susceptible to sunburn when you are outside in the sun or otherwise exposed to UV light. Again, remember that moderation is the key and you always need to use an SPF product when outside for extended periods of time.