The sun is vital for life and plays an important role in maintaining healthy skin and overall wellbeing. Sunlight supports vitamin D production, regulates mood, and helps the body’s natural rhythms stay in sync. However, while moderate sun exposure is beneficial, too much can damage skin cells and increase the risk of cancer. Understanding how ultraviolet (UV) radiation affects the body helps explain why balance and protection are key.
The Benefits of Sunlight
Sunlight triggers the skin to produce vitamin D, a nutrient essential for bone health, immune function, and inflammation control. Adequate vitamin D levels help the body absorb calcium and phosphorus, supporting strong bones and teeth.
Exposure to natural light also influences the circadian rhythm, the body’s internal clock that regulates sleep, hormone release, and metabolism. Morning sunlight, in particular, helps improve alertness and mood by stimulating serotonin production.
Moderate sun exposure can even support certain skin conditions, such as psoriasis or eczema, by reducing inflammation and slowing abnormal cell growth when managed under medical supervision.
When Sun Exposure Becomes Harmful
The same UV rays that help the body produce vitamin D can also cause harm when exposure is excessive or unprotected. The sun emits two main types of ultraviolet radiation that affect the skin:
UVA rays penetrate deeply into the skin, contributing to premature ageing, wrinkles, and DNA damage.
UVB rays primarily affect the skin’s surface, causing sunburn and directly damaging DNA in skin cells.
Both UVA and UVB exposure can lead to mutations in the DNA of skin cells. Over time, these mutations can disrupt normal cell growth and repair processes, allowing abnormal cells to multiply uncontrollably, and THIS is how skin cancer begins.
How UV Radiation Causes Cancer
UV radiation damages the DNA inside skin cells by altering the genetic code that controls cell division and repair. Normally, the body can detect and fix this damage, but repeated or intense exposure overwhelms these repair mechanisms.
When DNA damage accumulates, it can activate oncogenes (genes that promote cell growth) or deactivate tumour suppressor genes (genes that control cell division and repair). This imbalance allows damaged cells to grow unchecked, forming tumours.
The three main types of skin cancer linked to UV exposure are:
-Basal cell carcinoma (BCC): The most common and least aggressive form, often appearing as a pearly bump or sore that doesn’t heal.
-Squamous cell carcinoma (SCC): Can develop from long-term sun exposure and may spread if untreated.
-Melanoma: The most dangerous type, arising from pigment-producing cells (melanocytes) and capable of spreading rapidly to other organs.
Protecting the Skin While Enjoying the Sun
Healthy sun exposure is about balance. A few minutes of sunlight on the skin several times a week is usually enough for vitamin D production, depending on skin tone, location, and season. Beyond that, protection becomes essential.
Effective sun safety includes:
-Applying broad-spectrum sunscreen (SPF 30 or higher) daily, even on cloudy days.
-Wearing protective clothing, hats, and sunglasses.
-Seeking shade during peak UV hours (10 a.m. to 4 p.m.).
-Avoiding tanning beds, which emit concentrated UV radiation.
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References:
-https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/sun-uv-and-cancer/how-does-the-sun-and-uv-cause-cancer
-https://www.canceraustralia.gov.au/resources/position-statements/lifestyle-risk-factors-and-primary-prevention-cancer/lifestyle-risk-factors/uv-radiation
-Current insights and future perspectives of ultraviolet radiation (UV) exposure: Friends and foes to the skin and beyond the skin https://www.sciencedirect.com/science/article/pii/S0160412024001211