Sunshine and Exercise

We are encouraged to exercise daily. With all the news and talk about skin cancer and even melanoma, is it safe to exercise in the sun every day? I don’t manage well exercising indoors, and prefer walking outdoors.

We do indeed encourage daily exercise. The question often asked in church circles is: “Even on Sabbath?” Yes, indeed!

We have been designed to move, and our efficiency and well-being in all dimensions—physically, mentally, spiritually, and emotionally—is enhanced by regular, moderate exercise. Before answering your question on the possible danger of sun exposure, let’s briefly review the benefits of sunshine, and how it may influence our health.

What else could better complement the refreshing feeling of the breeze on one’s face following a rain shower than warm, welcoming, and comforting rays of sunshine? Sunshine adds sparkle to the water and changes the hues of the air, depending on the time of day. It gives light, not only so we may see, but also to aid our metabolism of calcium by producing vitamin D precursors in the skin. With all these natural health-promoting agents—air, water, and sunshine—placed together, one may conclude that the environment was planned with humankind in mind. We and the world we inhabit are wonderfully designed and created!

The sun is central to the provision of energy to our planet. Much of its radiation promotes health and well-being. It is essential for the growth of plants, vegetation, and photosynthesis, the food-production mechanism. This, in turn, impacts the lives of all who eat. Sunlight powers the recycling of water through its evaporation into the clouds and its distillation as rain.

Dermatologists have noted a causal relationship between sunburn and skin cancer, especially if there’s been excessive exposure in childhood.

Sunshine converts cholecalciferol, the precursor of vitamin D, into active vitamin D. This important vitamin helps ensure the maintenance and repair of our bones, but also has been found to have many other important effects. Many people lose out on these benefits because of working long hours indoors and having insufficient exposure to the sun.

Darkly pigmented skin does not permit the sun’s ultraviolet rays to work efficiently in the production of vitamin D, resulting in lower levels. This is aggravated in people who live in the extreme northern or southern parts of the world.

You wisely ask about the safety of exposure to sunshine and possible risks related to damaging ultraviolet (UV) rays. Dermatologists have noted and shown a causal relationship between sunburn and skin cancer, especially when there is excessive exposure in childhood. It’s important to use appropriate sunscreen protection; this does, however, decrease vitamin D production.

Paradoxically, vitamin D is thought to be an important factor in controlling the growth of other cancers, such as prostate cancer. Sunlight exposure, therefore, is important to health. The safest times to benefit from sunshine are before 10:00 a.m. and after 4:00 p.m. Exposure without sunscreen should be limited to 20 minutes.

In summary, choose the times you exercise outdoors and avoid being in direct sunlight for prolonged periods. And most important, live in the warmth of the presence of the Son of righteousness, Jesus Christ!

Peter N. Landless, a board-certified nuclear cardiologist, is director of the General Conference Health Ministries Department.