How Much Sun Is Too Much – Or Enough?

by Dr. John Beasley, M.D
Aviation Medical Examiner, Professor Emeritus and Clinical Professor
Department of Family Medicine – University of Wisconsin – Madison

A couple of recent articles said: “Sun Protection is vital for all” and “If you don’t need a flashlight, you should be using sunscreen.” Gimme a break! Do you really want to stay indoors all the time or slather on goo whenever you go out? Many of us enjoyed a fine time at last summer’s AirVenture where there was lots of sun and perhaps some of us got a bit extra. Sunshine, like many things in life, is fine – perhaps even good for us – in moderation, but perhaps not in excess.

Sure, for most of us (especially those of us with lighter skin) excessive sun exposure does lead to accelerated ageing of the skin, and it increases the risk of skin cancers. And, for you younger pilots, most sun damage is done in your teens and 20s. Actually, by the time one gets to “senior” status, most of the damage has been done.

There are several conditions associated with excessive sunlight. The most common are actinic keratosis. These appear as slightly roughened, scaling spots, commonly on the face or other sun-exposed areas. They feel a little like sand paper.  About 1 in 100 of these can become skin cancers, and they are most often treated with freezing to get rid of them. Other treatments are available, too.

Next up the list are basal-cell cancers. They appear as non-healing spots often on the face, but they can be found nearly anywhere. They tend to have a slightly raised border which has a pearly appearance. Usually they can just be excised and that’s the end of the problem, as long as they are not allowed to get too big. Spreading throughout the body is exceedingly rare. About 80% of skin cancers are of this type.

Then we come to squamous cell cancers. These tend to arise from the actinic keratosis and most often are flat, and again, non-healing areas. Generally, just local excision or other treatment takes care of them, although they can spread. They should be treated while they are still small and before there is a risk of spreading. About 16% of skin cancers are squamous cell.

Finally, comes the bad one – malignant melanoma. These can spread and kill and are about 4% of skin cancers. They should be caught early. Google up “ABCDE Melanoma” and you’ll get both instructions and some images of what these look like. If caught early and excised, the cure rate is around 95%. Melanoma tends to be associated not just with sun exposure, but with frank sunburn. There is also some tendency to run in families. The average person has about 1 chance in 50 of developing melanoma during their lifetime. If you have light, easily burned skin, a family history for melanoma and a history of bad sunburns, you have higher risk. At the same time, there is a bit of a national neurosis developing about sun exposure.

Last year during the summer, I got a call from a nursing home asking if they could have an order to apply sunscreen to my 88-year-old patient before she went outside. Good Grief! At 88, she ought to just go outside and enjoy the sun and not worry. More seriously, we’re also seeing more clinically significant vitamin D deficiency and even perhaps an increase in some diseases such as multiple sclerosis (which may have some possible link to inadequate vitamin D).

There is also some evidence that sunlight, especially in the winter, can help alleviate some depressive symptoms. (During the winter, I try to get my exercise outside over the noon hour in the sun when I can. It helps me to avoid “seasonal grumpiness disorder”.)

So, it’s the sunburn that is really bad. Moderate exposure isn’t so bad (especially if you have darker skin) and the damage done is limited. Broad-brimmed hats, sunscreen use (slather it on), and avoiding sunburn are helpful. But don’t be “solar-phobic” and live indoors.