What is Lux?

Lux is a measurement used to show how intense the level of illumination is on a certain object. It’s critically important when trying to understand light and darkness. During the day, light intensities outside can reach illuminances up to 100,000 lux in direct sunlight and 25,000 lux in full daylight. Light intensities in closed rooms are considerably lower and standard office and home lighting is often lower than 500 lux. Our eyes, that conversely communicate with the brain, need to be illuminated by around 500 lux to trigger certain processes within the body. When this happens, our body wakes us up naturally, physiological function operates in a better fashion and we ultimately find rest and sleep much easier.

Light and the Circadian Rhythm

The Circadian Rhythm is the cycle of 24 hours, integral to the internal clock within the body. This rhythm is essential for all the processes and functions that our body goes through. In fact, the sleep-wake cycle is one of the most important circadian rhythms. This internal body rhythm is influenced by various factors, the most important one of them being light. All the circadian rhythms in the body have a connection to the master clock in our brain, located in the suprachiasmatic nucleus(SCN), and featuring different clock genes. These emit different signals from the SCN to the body to trigger different activities. The signals sent by the SCN are triggered by various external cues. This includes our light exposure, and this is why the circadian rhythms and light are closely connected.

Light and our hormones.

There are two main hormones at play when we talk about sunlight and darkness. Serotonin and Melatonin. In short, our levels of melatonin are boosted when it’s dark, whereas serotonin levels increase when we expose ourselves to sunshine and light environments. Melatonin helps you get to sleep and serotonin helps you feel awake when you wake up. Serotonin is a neurotransmitter or chemical messenger, that’s involved in many physiological processes, not only waking up and regulating our circadian rhythm. It has also been shown to impact:

• Appetite
• Learning and Memory
• Positive feelings and sociable behaviour.

When we expose ourselves to this higher level of quality light, we produce serotonin and in turn, the body reduces its melatonin levels. Melatonin is the only known hormone synthesized by the pineal gland and is released in response to darkness, hence it helps us wind down and ultimately transition into sleep. With melatonin in the bloodstream, we can rest better during our sleep. If two people slept for 8 hours, one during daylight and another darkness, the person that slept in darkness would feel more rested. Many people who have sleep issues use artificial melatonin supplements to help them fall asleep, yet disregard light and it’s importance. Melatonin is produced from serotonin through a cascade of enzymatic reactions, so if we get our light exposure wrong or serotonin production wrong. It impacts our sleep.

Light Therapy?

Light therapy, also called phototherapy, has been studied in relation to numerous medical conditions, including:

• Insomnia
• Circadian rhythm disorders
• Dementia and Alzheimer's disease
• Parkinson disease
• Depression
• Post-traumatic stress disorder (PTSD)
• Seasonal affective disorder (SAD)

The discovery of lux and the effects of light on sleep and waking up has led to many innovations. One of these is light therapy. This type of therapy includes exposing people to an artificial light source for treating sleeping disorders, jet lag, seasonal depression, or merely adjusting sleep patterns.

So how does light therapy work?

Quite simply it’s about light exposure. A patient would sit next to a light source, often a “light therapy box,”. This emits light, similar in nature to the natural light that we can find outdoors, so often in excess of 10,000 lux. Simply put, it’s designed to artificially create the natural conditions we are exposed to when we go out in daylight. Light therapy affects various chemicals in the brain that regulate sleep and mood. This treatment is completely safe and has little to no known side-effects. If you work nights, you're up before dawn, or you can't access sunlight for any reason, a lightbox may be a viable alternative. For those of you that regularly travel across time zones and suffer from jet lag, it may also be of benefit.

Lack of Light and Insomnia

Our internal body clock is deeply tied to exposure to light. When we expose ourselves to high-quality light during the day, our internal clock adjusts to going down to a bed when it gets dark. Both of these are influenced by serotonin and melatonin production and the cool thing is, both conditions can be simulated positively or negatively.

A word from HMN24

Light is a significant factor that affects when we wake up and how. It can be an obvious trigger when we are exposed to light, but at the same time, the amount of exposure to light during the 24h cycle is also a critical factor in our long-term sleep-wake cycle. In reality, many of us have shifted our internal clocks to suit our busy lives and busy schedules and in both the long and short term this disrupts our mood, productivity and our abilities to perform at our very best. A few simple changes to how you expose yourself to light can have huge impacts on your overall productivity.