How it Works

Why is Sunlight Essential to Life?

Sunlight feels wonderful whether we are basking in it on the beach or feeling it shine on our faces from the window when we drink our coffee in the morning. Its warmth and golden beauty just feel good, and we often take it for granted. However, sunlight is essential to our health and survival, allowing us to live out happy and productive lives. 

For instance, exposure to it allows our bodies to produce various vitamins such as Vitamin D from cholesterol. Vitamin D has many roles in the human body and is crucial to optimal health. 

Indirectly, we need the energy from the sun to survive too, and here's why: We get our energy from the food we eat, and that food, of course, comes from the energy of the sun. In essence, if we didn't have that bright celestial body shining down on us, we'd starve!

The sun also helps the brain produce melatonin & serotonin, the hormones that directly impact important functions like moods, sleep cycles, energy levels and more.

Melatonin: The Circadian Rhythm Regulator

Humans have what is known as circadian rhythm, and it is how we manage our sleeping and waking cycles. Melatonin is a hormone and powerful antioxidant that is manufactured by the brain's pineal gland. It is also the regulator of our circadian rhythms. 

Darkness stimulates our bodies to produce melatonin, which lets us know that we are ready to go to sleep. When we are exposed to sunlight in the morning, we produce this hormone earlier, which helps us to get to sleep and stay asleep better once nighttime arrives. 

If you have trouble with your sleep/wake cycle, then the odds are high that your melatonin production levels are lagging due to you not getting enough bright light exposure.  

In a nutshell, melatonin is one of the body's most effective sleep aids. So getting regular exposure to the sun’s rays every day is needed to maintain healthy circadian rhythms. 

Serotonin: The Melatonin Converter

The hormone serotonin helps to regulate a variety of functions that contribute to a healthy lifestyle. Sunlight exposure stimulates and helps maintain serotonin production, which converts to melatonin in the body. Moreover, the hormone is not only important to sleep-wake cycles but also to mood regulation and digestion. 

Serotonin is also a neurotransmitter, meaning it acts as the chemical messengers in our central nervous system that relays messages to other parts of our body. Serotonin acts by transmitting signals between neurons, or from neurons to muscles. When serotonin performs this function, it regulates several bodily functions, such as appetite, energy intensities, memory, mood, sexual desire and more. 

The hormone's role in supporting various functions in your body means that it's a critical part of your health that can't be overlooked. It also means that sunshine is a key factor behind our ability to maintain good health and experience happiness and joy. 

Americans Aren't Getting Enough Sunlight

Blame it on video games, binge-watching Netflix, fear of skin cancer or merely from working indoors for a large portion of the day, but Americans aren't spending enough time outdoors soaking up the sunlight. 

To put it another way, a study by the EPA shows that people in the United States are spending 90 percent of their life indoors. That’s bad news since indoor lighting doesn’t maintain our circadian rhythms properly. 

Referencing the following chart that measures light in lux (how much light falls on a certain area), you can see that the intensity of indoor light levels is quite a bit lower than that of the sunlight you would find outside on a sunny day during springtime. 

You can also tell from comparing data in the chart that indoor lighting doesn’t provide anywhere near the quantity of lux exposure that’s necessary for maintaining a healthy sleep and wake cycle.

Shorter Days in the Winter Make Matters Worse

As if trying to get enough sun in the day wasn't hard enough, the days, along with the sunshine they offer, get shorter as we approach winter. Opportunities to get access to sunlight during this season get scarcer, as most of us head out to our jobs at the crack of dawn and leave at sunset. With that going on, we can consider ourselves fortunate if we get any sunshine whatsoever. 

Studies show that the amount of natural light our bodies need varies a good bit and depends on characteristics such as our skin tone & type, age and other factors. This lack of exposure during the colder months can decrease the production of melatonin and serotonin, which can lead to depression, insomnia and other circadian cycle-related disorders. 

What You Can Do About It

The shorter days of winter are already tough on our moods, productivity and energy levels. Without access to enough bright light during the day, it's no wonder that people who live in northern regions have a harder time coping with seasonal affective disorder (SAD) than others do!

There are many ways you can help your body get through the winter by getting more bright light exposure. Actions you can take range from opening blinds in your home when the sun comes out, to taking part in a sunny activity, or even traveling south for vacation. 

While it's not practical to try and get enough sunlight every day no matter where you live, there are many things you can do that will help prevent the negative effects of shortened days, including using bright light therapy lamps.

A Bright Light Therapy Primer

This therapy involves using a specialized device to deliver artificial lighting that is similar in strength to natural sunlight to your eyes. The treatment is also known as phototherapy and chromotherapy. 

Phototherapy is delivered via bright light therapy lamps, which are also known as happy lights or sad lamps because of the role they play in relieving SAD disorder symptoms. These artificial lights solve the problem that arises from not getting enough natural light— namely, that the body is not producing enough melatonin, serotonin and other mood-boosting hormones. 

Bright light therapy lamps deliver artificial lighting that helps us fall asleep easier at night, while also assisting us in feeling cheerful and more energetic. The therapy can help anytime, but it especially helps when we have limited exposure to the sun during the autumn and winter months.

Origins of Bright Light Therapy

The origins of the use of bright light therapy can be traced to ancient Greece, where physicians would shine sunlight into the eyes of their patients suffering from various mental disorders. 

In 400 BC, famed Greek physician Hippocrates wrote about the positive effects of natural light on a patient’s mental health and moods. Later, in the early 1800s, researchers discovered that additional exposure to sunlight helped psychiatric patients and patients with tuberculosis. 

In 1890, bright light therapy lamps became a reality. During that year, Danish physicist Niels Ryberg Finsen developed the carbon arc lamp. In a first, Finsen's device emitted ultraviolet radiation to treat tuberculosis.

SAD is Discovered

In 1984, researchers discovered how effective bright light therapy lamps really were. That year, Norman Rosenthal and other researchers published the first scientific description of seasonal episodes of depression known as SAD in the National Institute of Mental Health. The publication listed SAD as a circadian rhythm disorder for the first time, and Rosenthal cited exposure to light as being helpful in treating the mood disorder. 

Since Rosenthal's discovery, boxes equipped with powerful light bulbs have been used to provide this exposure to natural sunlight without having to go outside in cold weather or at all hours of the day. Today, personal light therapy lamps have become more easily accessible.