What is Light and How Does It Affect Us?

Light plays a fundamental role in our daily lives, profoundly impacting both our physical and mental well-being.  Our solar systems need sun to survive, feeding, plants, giving us oxygen to survive as well as giving us a source of heat. Natural sunlight is vital in regulating our body's biological clock, also known as the circadian rhythm, which governs sleep cycles and hormone production. Exposure to morning sunlight is especially beneficial, helping us maintain healthy sleep patterns and balance hormone levels. On the other hand, excessive artificial light can disrupt these systems, often leading to negative health effects. People who suffer from Seasonal Affective Disorder (SAD) face particular challenges, as their mood and well-being are closely tied to the amount of natural light they receive. It's also important to note that men and women are affected differently by light, and embracing natural daylight is crucial for optimal health.

Personal Reflection and the Importance of Sunlight

During a leisurely breakfast on Easter Monday, I had the opportunity to listen to an article on Women's Hour discussing the significance of light in our lives. The article highlighted that everyone, not just women, needs daily doses of sunshine to support their health and well-being. Some people thrive in summer while others prefer winter, but regardless of preference, the amount of sunlight we receive can have a marked impact on both our physical and mental health.

The Hypothalamus: Our Internal Regulator

Every person has a hypothalamus — a critical part of the brain responsible for regulating essential automatic functions such as body temperature, hunger, thirst, sleep cycles, and emotional responses. The hypothalamus performs these tasks by releasing hormones that control the pituitary gland, thereby influencing various bodily processes.

Our Biological Clock and Daylight

The routines and rhythms we establish are based on a 24-hour internal clock, which is consistent across all individuals, regardless of location or daylight hours. Scientifically, light is essential for keeping this biological clock in balance. Daylight helps set the tone for our day, supporting our internal timekeeping mechanisms.

Light and Daily Functioning

There is a strong correlation between our daytime functioning and our patterns of night-time activity and sleep. The quality and quantity of light we receive can make the difference between having a productive day or struggling to function.

Experiencing Natural Light

When stepping outside, many people experience an audible or internal sigh of relief. This reaction reflects the enjoyment and benefit of 'breathing in' natural light. While there is some evidence suggesting that artificial light can help with mood and clock regulation, there is limited data to support its effectiveness. Light therapy devices can assist those with SAD in winter, but such devices may be expensive, making natural sunlight the best and most accessible option. It is worth noting that some individuals experience reverse symptoms of SAD during spring and summer, which can complicate diagnosis.

The Science Behind Sunlight

When exposed to sunlight, our eyes contain photoreceptors — specifically, intrinsically photosensitive retinal ganglion cells (ipRGCs) — which are not involved in vision, but in regulating our biological clock and circadian rhythm. Sunlight triggers these cells, prompting the brain to release serotonin, the 'happy hormone' that enhances mood and helps synchronise our internal clock. Increased daylight also supports the release of melatonin, which is essential for sleep. Corrective lenses or glasses do not impede this process; they can actually help sunlight reach the necessary parts of the eye, allowing for vital vitamin D synthesis.

Managing Light Exposure for Better Health

Whilst exposure to early morning sunlight is beneficial, reducing light exposure in the evening can improve sleep cycles. Early risers experience a surge of cortisol, a stress hormone that motivates us for the day, especially when paired with morning daylight. The recommendation is to get sunlight exposure early in the day, but to avoid the peak hours of 11:00 to 15:00.

Artificial Light and Gender Differences

Reliance on artificial light can cause our bodies to lose touch with natural rhythms. Research suggests men receive 54% more light exposure than women. Women are more affected by artificial lighting from devices, resulting in lower melatonin levels.

Sensitivity to Light

Reflecting on these insights, I realise I am quite sensitive to light. In Scotland, there is a saying, 'Nae big lights!' — in my household, the main light is reserved for finding lost items or cleaning, while soft lighting is preferred otherwise. Even in the kitchen, I opt for gentle lighting, and I am mindful of how others illuminate their homes and environments.

Vitamin D and Its Role

Vitamin D is produced when UVB radiation from sunlight hits the skin, converting cholesterol into Vitamin D3. This vitamin is essential for bone health, immune function, and maintaining circadian rhythm. Adequate sunlight also supports our 16-hour waking cycle, promoting restful sleep.

Conclusion

Whether at the start or end of your day, reflecting on the importance of light can provide valuable insight into your daily habits and routines.

Support and Solutions

My practice in Solution Focused Hypnotherapy is here to assist you in overcoming life's challenges and changes. While it can be difficult, I am committed to helping you find the best solutions for your needs.

Information sources;  Women’s Hour Radio 4 https://www.bbc.co.uk/programmes/m002tpml; https://www.brainfacts.org/diseases-and-disorders/mental-health/2020/how-does-sunlight-affect-our-mood-120720;