How To Strike a Balance With Sun Exposure
We know that not enough and too much sun exposure is a problem for our health. As a result, it's critically important to understand that reducing the risk for one disease shouldn't be at the cost of increasing the risk for another.
It seems that the trend toward sun safety in recent years has led to fear of getting into the sun at all. We now typically avoid the sun between 11 am and 3 pm, which is when the UV index reaches a peak during the day. But is this really necessary? And, more importantly, is this avoidance causing other health problems?
The harmful effects of prolonged UV ray exposure are genuine, and in high UV regions such as Australia, we need to practise some sensibility with our approach. However, there is so much variation in the risk of sunburn and subsequent skin cancer development, depending on the time of year, geographical region and individual susceptibility.
There's increasing evidence that insufficient sun exposure is becoming a significant public health problem. Limited sun exposure has been linked to a laundry list of increased health risks, including breast cancer, hypertension, cardiovascular disease, diabetes, metabolic syndrome and multiple sclerosis. According to some studies, staying out of the sun may be just as harmful as smoking cigarettes!
So how do you strike the right balance between adequate exposure and remaining sun safe?
In my view, guidelines for sun safety need to be more balanced and tailored. Certain age groups as well as those at risk for developing chronic diseases should understand the inherent risks associated with limited sun exposure. Depending on the local UV intensity and skin type, national guidelines for sun exposure should be created with different health impacts in mind.
Here’s a guide for Australians on how much sunlight exposure to aim for in various parts of the country at different times of the year.
Sunlight Exposure Map
Now let’s dive into some of the health benefits of sunlight exposure.
Boosts Vitamin D Production
One of the most well-known health benefits of sunlight exposure is vitamin D production. Vitamin D is in fact more like a hormone than a vitamin. It plays a role in communicating with other cells in the body, influencing bone metabolism and improving immune function. Our bodies are able to synthesise vitamin D via pathways that first involve skin exposure to sunlight.
Getting a few minutes of sunlight each day (while being mindful not to overexpose or risk sunburn), has far-reaching health benefits. Some studies say that people who have low vitamin D are more likely to have autoimmune diseases. Some examples of these autoimmune diseases are type 1 diabetes, rheumatoid arthritis and some cancers.
An important distinction to make here is that vitamin D supplementation does not replace sunlight. In fact, supplementation with synthetic vitamin D does not in some cases have the same physiological effects that people think. One reason for this is the different formulations of supplements, relative magnesium status and the different dosages involved.
So, while supplementing can address a major and frank deficiency state, it's still important to encourage natural vitamin D synthesis by way of sunlight exposure wherever possible.
Improves Your Mood & Mental Clarity
Sunlight exposure can also improve your mood. When exposed to sunlight, our bodies produce serotonin, which is a hormone that has been linked to feelings of happiness and well-being.
People who live in regions of the world with less sunlight throughout the year may be susceptible to a condition called Seasonal Affective Disorder (SAD). This disorder is a type of depression that occurs at certain times of the year, usually during the winter months when there is less sunlight. Symptoms include lethargy, difficulty sleeping, difficulty concentrating, and feeling depressed or hopeless. It is believed to be caused by a biochemical imbalance in the brain brought on by a lack of sunlight exposure.
Fortunately, one of the best ways to treat SAD is to get more sunlight, often in the form of synthetic blue light therapy. Sunlight exposure is also known to boost serotonin levels in the brain and can help regulate other hormones such as melatonin that are related to sleep.
Bright sunlight exposure also helps with cognition, decision making and executive function, according to some research. A study published in Frontiers in neurology showed that a single 30-minute exposure to blue light influenced mood and cognition, affecting the amygdala and prefrontal cortex of the brain together. Response times to tasks and dopamine centres are equally improved and increased by light exposure, even in small doses.
Reduces Stress & Anxiety
Cortisol is the body's primary 'wake-up' hormone. It naturally starts to rise just before the sun comes up each morning, and has a natural peak and trough sequence during the day. However, chronically elevated cortisol levels can lead to weight gain around the stomach area. This phenomenon is known as central adiposity, and is a well-known risk factor for the onset of chronic diseases including diabetes, fatty liver disease and cognitive decline.
Bright light exposure is one proven way to help with stress management and can help downregulate elevated cortisol in the body. If you’re feeling down or stressed out, getting some sun could be just what you need!
Influences Genes & Promotes A Long Life
We can now appreciate how important sunlight exposure is, as it sets our circadian rhythm. This circadian rhythm governs all kinds of processes, including a percentage of our genes. Certain genes that manage appetite, cell repair, immunity and neurotransmitter function are all influenced by sunlight exposure.
Could exposure to the sun actually lengthen your life and reduce cardiovascular disease? A Swedish study conducted over a 20-year period, involving nearly 30000 women deems this to be true. Conversely, the results demonstrated that those who avoided the sun had reduced life expectancies of 0.6–2.1 years.
Get Better Quality Sleep
When exposed to sunlight or artificial light in the morning, our melatonin production will start to rise earlier in the night. Typically, this onset of melatonin occurs around 16 hours after the initial exposure to bright sunlight, which makes it easier to fall asleep. This becomes especially relevant if you're trying to reset your sleep patterns. To do this, get some sunlight within the first hour of waking.
Sleep is a key element to optimal health that many people overlook. Each person’s sleep requirements will vary and good quality sleep facilitates a vast array of internal biological processes. Check out this ultimate sleep guide for more on understanding your individual sleep needs, plus tips on how to maximise high-quality sleep.
Enjoy The Health Benefits of Sunlight
It turns out that the health benefits of sunlight exposure go beyond vitamin D synthesis. Let the sun in your life and enjoy the many health benefits it brings, including longevity, improving your mood and getting a good night’s sleep.
Alkozei, A., Dailey, N. S., Bajaj, S., Vanuk, J. R., Raikes, A. C., & Killgore, W. D. S. (2021). Exposure to Blue Wavelength Light Is Associated With Increases in Bidirectional Amygdala-DLPFC Connectivity at Rest. Frontiers in neurology, 12, 625443. https://doi.org/10.3389/fneur.2021.625443
Aranow C. (2011). Vitamin D and the immune system. Journal of investigative medicine : the official publication of the American Federation for Clinical Research, 59(6), 881–886. https://doi.org/10.2310/JIM.0b013e31821b8755
Galima, S. V., Vogel, S. R., & Kowalski, A. W. (2020). Seasonal Affective Disorder: Common Questions and Answers. American family physician, 102(11), 668–672.
Jung, C. M., Khalsa, S. B., Scheer, F. A., Cajochen, C., Lockley, S. W., Czeisler, C. A., & Wright, K. P., Jr (2010). Acute effects of bright light exposure on cortisol levels. Journal of biological rhythms, 25(3), 208–216. https://doi.org/10.1177/0748730410368413
Lindqvist, P. G., Epstein, E., Nielsen, K., Landin-Olsson, M., Ingvar, C., & Olsson, H. (2016). Avoidance of sun exposure as a risk factor for major causes of death: a competing risk analysis of the Melanoma in Southern Sweden cohort. Journal of internal medicine, 280(4), 375–387. https://doi.org/10.1111/joim.12496
Lindqvist, P. G., Epstein, E., & Landin-Olsson, M. (2022). Sun Exposure - Hazards and Benefits. Anticancer research, 42(4), 1671–1677. https://doi.org/10.21873/anticanres.15644
Lindqvist, P. G., & Landin-Olsson, M. (2017). The relationship between sun exposure and all-cause mortality. Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology, 16(3), 354–361. https://doi.org/10.1039/c6pp00316h