3. Without light, there is no life.
Light is vital to support all forms of life. We need light to see, but we also need
light to support other bodily functions. With light we can affect mood, improve sleep
and treat depression. Light has a direct alerting effect and can affect productivity,
learning and memory consolidation.
The biological effect of light is bigger than most people are aware of. Light has an
effect on our biology and wellbeing that is greater than most people are aware of
and that goes beyond the visual effects of light.
For most people, modern living entails spending most of the day in closed rooms,
bathed in a sum of artificial and natural lights. Yet while artificial light has afforded
mankind incalculable possibilities, it has also caused some confusion in our
bodies, which have evolved for thousands of years to respond to the stimuli of
sunlight in the day and darkness at night. This responsiveness to natural light is
called the circadian rhythm or cycle.
4. THE CIRCADIAN
RHYTHM
Circadian rhythms describe the 24-hour biological cycle of almost all living beings and are primarily influenced by light reception,
but temperature and other stimuli also play a role in the process.
Our natural clock is in the part of the brain called the hypothalamus, which is linked to photoreceptors located throughout the body (such as
the retina). These receptors are responsible for synchronizing our internal clock with the light we absorb during the day. Understanding the
circadian cycle is essential because it affects the rhythms of the human body and influences sleep, mood, wakefulness, digestion,
temperature control, and even cell renewal. Research shows that an adequate amount of light improves mood and energy levels, while poor
lighting contributes to depression and other deficiencies in the body. The amount and type of lighting directly affect concentration, appetite,
mood, and many other aspects of daily life
The circadian rhythms of humans
5. Light is responsible for informing our circadian rhythms
The study of circadian rhythms and how they impact us is called Chronobiology. Specialists working in the field have shown that a number of
factors influence circadian rhythms and subsequently have an effect on our health. Our brains have a master clock called the suprachiasmatic
nucleus (SCN) that controls all our biological clocks and keeps them in sync with one another. The SCN sends signals to the brain to release
specific hormones at specific times of the day based on the light levels of a person’s surroundings, as they are perceived by their eyes.
And this is where problems can arise. As we now regularly find ourselves in environments with artificial lighting, our bodies are no longer
regulated exclusively by natural stimuli. Our internal clocks, then, become disrupted by changes in the normal pattern of day to night and the
physiological processes that occur in direct response to it become out of sync too. In fact, research carried out by the University of Toronto
shows that subjecting ourselves to “unnatural” strengths of light for a particular time of day can have negative effects.
6. People of the modern era spend most of their time in built
environments, such as offices, schools, shopping
malls, restaurants, showrooms. The physical properties of these
indoor spaces have various effects on the users. The most
important of these features is lighting. As evidenced by
researchers, we cannot ignore the positive or negative impacts of
light on individuals’ life and personal well-being quality.
Besides the visual effects of lighting, it also has biological and
effects that can impact the health and well-being of humans.
Natural or artificial, the influence of light can be on human
preference, perception, impressions, behavior, and mood.
On sunny spring days, we feel more active and happy compared
to dark winter days, or we are more productive in a well-
illuminated office. These differences show us that we need more
light than we need to see.
LIGHT EFFECTS
7. We can classify these effects in two groups:
• Visual effects: vision, perception, information.
The lighting quality should always provide sufficient visual performance for the task concerned.
Average illuminance level, uniformity, glare restriction, and color rendering are the quality
parameters for a visual quality aspect.
Poor lighting makes it difficult to see documents or computer screens due to insufficient lighting
levels, glare, or unwanted shadows; reduces environmental, objects, and color perception, leading
to security problems and errors.
• Nonvisual effects: well being, mood elevation, high productive capacity, alertness,
responsiveness.
Without proper synchronization, the individual cellular clocks work at their own pace, causing a
misalignment. Chronic sleep and circadian rhythm disruption is associated with short- and long-
term health effects, including:
In terms of biological effects, lighting has an crucial impact on our biological clock
and hormones such as cortisol (stress hormone) and melatonin (sleep hormone) so it can improve
or disrupt our sleep and have a impact on our mood; this means that lighting influences our health,
well-being, and alertness leading to a weakened immune system, increasing risk of infections and
cancer.
In terms of physiological effects, lighting can decrease depression and help us to adapt to our
environment.
Other effects of light on humans are diseases that demonstrate seasonal and diurnal patterns.
Seasonal affective disorder (SAD) is an example, occurring more frequently during the darker
months of the year (SAD is a mood disorder that is caused by symptoms of depression during
certain times of the year, usually during the winter).
8. Lighting Systems with Brightness Controls
One of the best, most accessible solutions for this problem is the installation of interior lighting solutions with built-in brightness controls. By
enabling users to adjust the brightness (also referred to as the intensity or the Lux level) of the light emitted depending on the time of day, the task
being performed and the age of the users themselves, LED lighting systems with brightness controls can be tuned in real-time to match our
natural body clocks. For example, the interior lighting systems in hotels can be set to change throughout the day so that guests feel energized in
the mornings and relaxed in the evenings by ensuring that their brains release the correct levels of melatonin (the hormone that makes us sleepy)
at the correct time of day.
Entire lighting schemes can be designed to incorporate such functionalities and operate using centralized control systems. By partnering from the
outset of a project, designers can work alongside their manufacturers to ensure that the interior lighting created for their space is optimized to help
them achieve particular objectives…commercial, aesthetic, environmental or otherwise.
The colour temperature of an LED light is measured in Kelvin (K)
The Color Temperature of Lighting
The color temperature of light is another factor that massively affects our bodies. Warm lights (those with a lower color temperature) appear less
bright than cool lights (those with a higher color temperature). The temperature, then, refers to the color that the light being emitted appears to our
eyes. It is measured using the Kelvin scale relative to the color of a ‘theoretical black body’ – a piece of metal that, when heated gradually,
changes in color from red to white. Visually warmer lights, then, actually have lower color temperatures and visually cooler lights have higher color
temperatures because the Kelvin temperature of the theoretical black body is lower when it is less hot and vice versa.
9. But, how does this affect us in practical terms day-to-day? We know that
whiter, cooler lights make an environment feel more energized and
stimulating. Rooms lit in this way make us feel more alert to our surroundings,
more focused on what we’re doing and can invite us to be more productive.
Conversely, warmer lights make an environment feel cozier and more
welcoming. This is why they’re used in romantic restaurants, for example, as
they encourage intimacy and relaxation.
Warm lighting creates an intimate, relaxed atmosphere at the 14
Hills bar
With the colour temperature of interior lights having such a fundamental impact on
our emotions and moods, we’re given the opportunity to use interior lighting
strategically. We can do this by specifying lights that are most appropriate for the
environment we’re trying to establish and most helpful in encouraging people to
behave in a certain way. We’ve already taken the example of restaurants, but there
are lots of other spaces (both public and private) that can be improved through
appropriate lighting. Cool white lights, for example, are perfect for meeting rooms
aand offices where people need to be switched on, concentrate hard and work
productively. At the other end of the scale, warm white lights are ideal for places like
hotel bedrooms, bars and luxury clothing stores.
Cool lighting creates a high-energy atmosphere inside Schuh stores
