Aurora – Light: How Light Affects Mood, Energy and Focus

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In our modern indoor lifestyles, we spend an average of 90% of our time indoors.[1] This can limit our exposure to natural sunlight, making it difficult to tap into its benefits for our wellbeing, of which there are many.

Most people understand that sunlight is essential for life on earth, providing warmth, light, and supporting plant growth. Animals, like us, have also developed daily cycles that work in sync with the sun. These cycles, known as our circadian rhythms, include processes such as our rest and digest and sleep-wake cycles. How well these cycles function can have knock-on effects to our wellbeing, including mood and alertness.

Morning sunlight in particular acts as ‘nature’s cup of coffee’, giving our bodies a powerful wake-up signal that boosts energy, improves mood, and sets our circadian rhythm cycles for the day ahead. The brightest artificial light in the morning simply doesn’t provide the same energising effects. However, artificial light can still play a positive role in how we feel and function.

Understanding the different effects of natural and artificial light allows you to take advantage of both to improve your wellbeing throughout the day.

Differences Between UV-Containing Sunlight and Artificial Light

Intensity and Spectrum of Light

Sunlight:

Natural sunlight is extremely intense, providing on average 10,000 to 100,000 lux (a measure of light intensity) depending on the time of day. For example, full sunlight is around 100,000 lux or more. An overcast day could go as low as 1,000 lux.[2]

Sunlight covers the full light spectrum, including ultraviolet (UV) rays, which are essential for processes like mood and energy regulation. The sun really can make us feel positive and engaged. It’s no wonder people seem happier in the summer.

Artificial Light:

Standard indoor lights, such as LED (Light Emitting Diode) and fluorescent lights, lack both the intensity and full-spectrum qualities of natural sunlight. Without UV rays and adequate blue light, artificial light cannot fully mimic sunlight’s impact, particularly in boosting morning alertness and aligning the body’s circadian rhythm. People may view blue as ‘bad’ because it keeps us awake at night, but during the day, this is exactly what we need.

Seasonal Affective Disorder (SAD): For some, standard artificial lighting and winter sunlight may not be enough to sustain a positive mood and appropriate energy levels. This can lead to a condition known as SAD. Light therapy boxes, which simulate bright, full-spectrum sunlight (typically around 10,000 lux), can be beneficial in these cases. However, it’s essential to use light boxes under medical guidance due to potential side effects like eye strain, headaches, and sleep disruption. For safety reasons, use medically certified products.

Blue Light and Circadian Signals

Sunlight in the Eyes:

Exposure to natural blue light from the sun, especially in the morning, activates the suprachiasmatic nucleus (SCN) in the hypothalamus. This suppresses melatonin (the sleep hormone) and boosts serotonin and normal levels of cortisol, which in turn stimulate adrenaline. Together, these processes support healthy alertness, mood, and energy for the day.

Cortisol and Adrenaline: Cortisol often gets a bad rap due to its link with chronic stress, but it plays a crucial role in keeping us alert and energised. Naturally rising and falling throughout the day, it acts as a key wake-promoting hormone, with levels peaking in the morning to boost alertness. Adrenaline works alongside cortisol, increasing heart rate and energy availability to prepare us for action.

Both hormones surge during stressful moments, helping us think quickly and respond effectively—a survival mechanism inherited from our ancestors. The challenge today is that while we no longer face constant physical dangers, we are often stressed by modern sensory triggers, many of which we don’t consciously recognise. Adding psychological pressures to the mix amplifies these stress responses, potentially leaving us in a heightened state of tension.

Natural Indoor Light: Natural indoor light doesn’t reach our eyes directly, but it still significantly impacts our well-being and performance. For instance, one study found that students performed better on exams when in rooms with windows compared to windowless rooms.[3] This might seem extreme, but it demonstrates how natural light affects our cognitive skills. Now consider how many meetings and conferences are conducted in windowless rooms. Clearly the audience cannot be as engaged as they could be in room with natural light.

Artificial Light:

Although artificial light emits some blue light, its intensity is often too low to effectively trigger wake-promoting responses. As a result, cortisol isn’t optimally stimulated, and melatonin, the hormone that promotes sleep, decreases more slowly. This can leave us feeling groggy and sluggish in the morning.

However, prolonged exposure to blue light from screens in the evening has the opposite effect, keeping us awake longer than our natural rhythms are designed to handle. Our bodies evolved to produce melatonin as the sun sets, signalling it’s time to wind down and rest. Evening screen use disrupts this process and can throw off our circadian rhythm.

Vitamin D and Endorphin Production

Vitamin D Synthesis:

Sunlight exposure triggers vitamin D production in the skin. Many people correctly associate vitamin D with bone strength, but it is also essential for other functions such as mood regulation immune function and critical thinking. Low vitamin D levels are very common with our indoor lifestyles which can contribute to fatigue and mood disturbances.

Endorphin Receptors:

UV exposure from sunlight stimulates endorphin release through receptors in the skin, providing a natural ‘feel-good’ effect that artificial light cannot replicate.

Natural light is clearly essential for our wellbeing on many fronts, but with indoor lifestyles and concerns around skin cancer and aging, how much time should we spend outdoors?

Have Your Time in the Sun

Appropriate sun exposure times depend on a variety of factors such as the intensity of the sun, your health, skin type and sensible measures to protect against sun damage and skin cancer. This is why you can find different recommendations.

For vitamin D, most advice focuses on late morning to early afternoon sun. This could be as little as 5-10 minutes a few times a week in summer for example and a bit longer in winter. In terms of sun safety, The World Health Organisation sites a UV rating of 3-5 as a moderate risk of skin damage, and above 6 as high to very high. A UV rating of 3 and above requires sun protection measures to avoid skin damage.[4]  

For the energising and feel-good benefits of UV light, morning light supports you the best to be as energetic, productive and positive as you can be. Most recommendations are for at least 15 minutes outside. Again, this is all dependent on the sun’s intensity, but it’s generally a good starting point. Remember, cortisol and endorphins are dependent on light reaching your eyes. This means sunglasses can limit how much light is registered by your hypothalamus. Depending on the glare and your health, try not to wear them for a few minutes if possible.  

To get the benefit of the sun while protecting your skin, it is best to refer to your local sun safety guidelines and seek professional advice if you have any specific concerns.  

Making time for 15 minutes outside in the morning and a 5-minute lunch time break outside, is an example of how you can use natural light to boost your energy and mental fortitude while supporting the overall health of your circadian rhythm. If walking is out of the question, perhaps can you sit by an open window while you have your breakfast. If this is also not possible, if you drive, can you open a car window?  Consider how you can make this work in your life at least a few times a week. The benefits are too great to deny yourself your time in the sun.  

How to Use Artificial Light

Although sunlight is the gold standard for regulating the sleep-wake cycle, artificial light can be helpful for activities like work and evening relaxation.

First, it’s important to know how to refer to the characteristics of light.

Definitions: Kelvin, Lumen, and Lux

Kelvin (K):

Kelvins measure colour ‘temperature’. This is all about the appearance, not actual heat.  Lower values (2000–3000K) have a warm yellow and orange colour, while higher values (5000K and above) produce cool white and bright daylight colours.

Lumen:

A lumen measures the total visible light emitted by a source. For example, a candle has a lumen around 12-15.

Lux:

Measures light intensity on a surface. This intensity can appear different depending how far you are from the light source.  For example, one metre from a candle will produce around 1 lux.

When buying lights, you commonly find the Kelvin and Lumen ratings on light packaging. That is, the colour effect of the white light and how much light it produces.  

 

Using Artificial Light for Focused Work

Artificial light, especially bright LED or full-spectrum lighting, can help maintain energy and focus during the day.

Optimal Brightness:

Choose bulbs around 500 lumens (home office example) to 1000 lumens (company office) for adequate brightness during focused work periods. Avoid overly intense lighting, as it can cause eye strain and fatigue over extended periods.

Colour Temperature:

A colour temperature between 4000K and 5000K works well in office settings for balanced alertness without overstimulation. A higher Kelvin may suit people doing very detailed work or for shorter high energy sessions such as brainstorming.

Light Angle:

If using a desk lamp, position it at a 45-degree angle to the side of your workspace, so the light illuminates your work area without directly shining into your eyes. This helps reduce glare and eye strain, making it easier to work comfortably. A lamp gives you the flexibility to use a warmer bulb in the evenings to reduce the negative effects of blue light as well.

 

 

Creating a Restful Evening Environment

In the evening, using warm, dim lighting supports relaxation by mimicking the low light levels of sunset.

Warm Lighting:

Use bulbs in the 2700–3000K range to create a warm, calming glow that minimizes blue light exposure. This colour temperature is ideal for preparing the body for rest by not interfering with melatonin production.

Low-Intensity Lamps:

Choose lower-lumen lamps (around 300–500 lumens) to provide gentle, ambient light.

Screen Management:

 Reduce blue light from screens by enabling “night mode” on devices or using blue light filters. These settings adjust screen colour temperature to warmer tones, which is less disruptive to melatonin.

Night Reading Lights:

For reading a book or papers before bed, try a 2700K–3000K reading light with adjustable brightness. Clip-on book lights with this temperature are another way to minimise blue light exposure. There are also various models of e-readers that minimise blue light, such as adjustable warm light, automatic blue light reduction and e-ink technology which produces no blue light but still requires a front light source with a warm light feature.

Shine a Light on Your Sense of Wellbeing

Natural sunlight, particularly in the morning, is unmatched for energising the body and setting the day’s rhythm. Artificial light simply can’t replicate this. However, when used wisely, artificial light can be adjusted to support different types of work during the day and provide restful lighting in the evening. By understanding the types, intensity, and timing of light exposure, you can create a lighting environment that aligns with your body’s natural rhythms, improving mood, energy, and sleep quality.

Unfortunately, it is not possible for one article to explain all the ways you can use light to improve your sense of wellbeing. To learn more about how light and sensory stimuli influence your mood and behaviour, visit Nriched Living and follow Total Sensory Wellbeing on Instagram.

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References:

[1] Department of Climate Change, Energy, the Environment and Water. (2021) 'Indoor air'. Australian Government. Available at: https://www.dcceew.gov.au/environment/protection/air-quality/indoor-

[2] Engineering Toolbox (n.d.) ‘Light levels in rooms’, Engineering Toolbox. Available at: https://www.engineeringtoolbox.com/light-level-rooms-d_708.html.

[3] Alotaibi, M., Alghamdi, R. and Bassam, A. (2020) 'The influence of natural light on intellectual performance among university students', Sustainability. Available at: https://www.mdpi.com/2071-1050/12/10/4167.

[4] World Health Organization (WHO) (n.d.) 'Radiation: The ultraviolet (UV) index', WHO. Available at: https://www.who.int/news-room/questions-and-answers/item/radiation-the-ultraviolet-(uv)-index.