A few words about what light means in our lives.
The main source that generates light for us is the Sun. The Sun emits several types of rays. The most important are:
1.-Ultraviolet (UV) rays. These are emitted by the sun in different wavelengths, including UVA, UVB and UVC. These rays have benefits and detriments for living beings.
Benefits of UV rays:
– Vitamin D: Exposure to UVB radiation allows the skin to produce vitamin D, essential for bone health.
– Circadian rhythm regulation: Sunlight, which includes UV rays, helps regulate the circadian rhythm and improves mood and sleep quality.
Harm from UV rays:
– Sunburn: Excessive exposure to UVB rays can cause painful sunburn on the skin.
– Skin damage: UVA and UVB radiation can damage the skin, causing premature ageing and increasing the risk of skin cancer.
– Eye damage: Prolonged exposure to UV rays can damage the eyes and increase the risk of cataracts and other eye problems.
2.-Infrared (IR) rays: Infrared rays are a form of thermal radiation emitted by the sun.
Benefits of infrared rays:
– Warmth: Infrared rays provide warmth, which is essential for maintaining the Earth’s temperature and the well-being of living things.
Harm of infrared rays:
– Overheating: Excessive exposure to infrared rays can cause overheating and dehydration in living beings.
Solar radiation, in general terms, including UV and infrared rays, has essential benefits such as vitamin D production and circadian rhythm regulation, but it can also cause damage to the skin, eyes and increased risk of disease. It is important to take precautions, such as wearing sunscreen and sunglasses, to minimize the harmful effects of solar radiation and to reap its benefits safely.
Let’s talk about the differences between sunlight and artificial light, in all its varieties.
Sunlight and artificial light are sources of illumination that have several important differences in terms of their origin, characteristics and effects.
Some of their significant differences are as follows:
Differences in their origin:
Sunlight. It comes from the sun and is a natural light source. It contains a wide range of colors and wavelengths, including ultraviolet (UV), visible and infrared.
Artificial light. This is generated by human-made devices, such as light bulbs, fluorescent tubes, LED lamps, etc. It can be produced using different technologies and energy sources, such as electricity, gas, or chemicals.
Differences in spectral composition:
Sunlight. It contains the entire spectrum of visible colors, which makes it suitable for color perception and plant photosynthesis. It also emits ultraviolet (UV) and infrared rays.
Artificial light. This varies according to the source. For example, incandescent bulbs tend to be warmer and yellower, while fluorescent and LED lamps can be adjusted to produce different color temperatures, from warm to cool light.
Differences in intensity and dimming:
Sunlight. The intensity of sunlight varies throughout the day and depends on factors such as geographical location, climate and time of day. It cannot be regulated directly.
Artificial light. The intensity of artificial light can be easily controlled by switches, dimmers and programming. This allows the lighting to be adjusted according to specific needs.
Differences in duration:
Sunlight. The availability of natural sunlight is limited to daylight hours and varies according to season and geographical location.
Artificial light. Artificial light is available throughout the day and night, making it useful for illuminating spaces at any time.
Differences in energy efficiency:
Sunlight. This is energy efficient, as it does not require additional energy consumption.
Artificial light. Its energy efficiency depends on the type of source and technology used. LED lights, for example, are known to be very efficient compared to incandescent bulbs.
Sunlight is a natural light source that contains the full spectrum of colors. In contrast, artificial light is generated by artificial devices, can vary in spectral composition and is dimmable. Both sources have important applications in everyday life and in the illumination of spaces, each with its own advantages and disadvantages.
All indications are that we should regularly sunbathe.
Now let us see how beneficial it is to WALK outdoors under the sun’s rays and how long it is advisable to walk outdoors without harm, as well as the care that should be taken when walking in the sun.
Walking outdoors in the sun can be beneficial to your health, but it is important to take precautions to avoid damage from excessive sun exposure.
GENERAL RECOMMENDATIONS.
Appropriate times:
Walking outdoors should be avoided during the hours of highest solar intensity, which are usually between 10 am and 4 pm. Instead, opt for walking in the early morning or late afternoon, when the sun’s rays are less intense.
Duration:
The amount of time you can safely walk in the sun depends on several factors, such as geographical location, skin type and intensity of solar radiation. As a general rule, it is not recommended to be out in the sun for long periods without protection, especially at peak hours. You can start with short walks, 15-30 minutes, and gradually increase the duration.
Sunscreen:
If you are scheduled to walk during the day, sunscreen should be used on all exposed areas of the skin, even on cloudy days. Use a broad-spectrum sunscreen with a sun protection factor (SPF) appropriate for your skin type. Reapply sunscreen every two hours or after sweating (Future Post WALKING AND SWEATING) or swimming.
Appropriate clothing:
Clothing that covers the skin should be worn, such as long-sleeved shirts, long trousers and a wide-brimmed hat to protect the face and neck. Look for clothing with ultraviolet protection factor (UPF) if you are in a very sunny environment.
Sunglasses:
Wear sunglasses that block UVA and UVB rays to protect your eyes from the sun’s radiation.
Hydration:
Carry enough water on every walk and stay well hydrated while walking, especially in hot climates. Sun exposure can increase fluid loss through perspiration (Future Post WALKING AND PERSPIRATION).
Shade:
Seek shaded areas or plan walking routes that include natural shadows, such as trees (Parks or forests) or buildings (city), to reduce direct sun exposure.
Listen to the body (Posts BODY PARTS FOR WALKING – THEIR CARE; LISTENING TO OUR BODY WHILE WALKING-BODY LANGUAGE):
Pay close attention to the body’s signals. If you feel excessively hot, dizzy, fatigued or reddened skin, seek shelter and rest.
Walking outdoors in the sun is healthy, but it is essential to take measures to protect yourself from the harmful effects of solar radiation. Scheduling walking times conveniently, using sunscreen, wearing appropriate clothing and staying hydrated are all essential precautions to enjoy walking without being harmed by exposure to the sun.
The sun’s rays and daylight are closely related to circadian rhythms (Post THE WALK AND CIRCADIAN RHYTHMS-PART I; Future Post WALKING AT NIGHT. CIRCADIAN EFFECTS), which are the natural patterns of activity and rest that regulate the sleep-wake cycle and other biological functions. Exposure to daylight, particularly sunlight, plays a key role in regulating these rhythms.
Highlights of circadian rhythms that we should be aware of and take into account:
Light as an environmental signal: The circadian system of living beings, including humans, is influenced by environmental signals, light being one of the most important. Light acts as a key signal that informs the body about the time of day and night.
Regulation of the biological clock: In the brain, there is a structure called the suprachiasmatic nucleus (SCN) that acts as the “master clock” of the circadian system. This nucleus is located in the hypothalamus and receives information from light via the photosensitive retinal cells in the eyes.
Light and melatonin production: Exposure to light, especially sunlight during the day, inhibits the production of melatonin, a hormone that promotes sleep. Daylight, rich in blue light, signals the body that it is time to be awake and alert.
Regulation of sleep and wakefulness patterns: Exposure to sunlight during the day helps keep circadian rhythms aligned with the planet’s 24-hour cycle. This helps regulate sleep and wakefulness patterns, promoting restful sleep at night and alertness during the day.
Influence on mood and well-being: Sunlight also has an impact on mood and well-being. Exposure to natural light during the day can increase the production of serotonin, a neurotransmitter related to feelings of happiness and well-being.
Sleep disorders: Lack of adequate exposure to daylight, as occurs in night workers or people who spend long periods indoors without natural light, can desynchronise circadian rhythms and contribute to sleep disorders and health problems.
In short, sunlight and daylight are essential for regulating our circadian rhythms, which affects the quality of sleep, mood and overall functioning of the body. Exposure to sunlight during the day is important for maintaining a healthy biological clock and a balance between sleep and wakefulness.
Let’s look at some situations that we must take into account with the SHADOW:
Shade plays an important role in people’s health and well-being, and its relationship with sun exposure is crucial to understanding its effects. The following explains aspects related to shadow and its influence on health:
Benefits of shade:
Protection against solar radiation: The shade provides protection against direct solar radiation, including ultraviolet (UV) rays that can damage the skin and eyes (Post THE SENSE OF SIGHT AND THE WALK-RWD SYSTEM; Future Post WALKING AND THE EXTERNAL AND INTERNAL SENSES). Staying in the shade is an effective way to reduce the risk of sunburn and premature skin aging, as well as the risk of developing skin cancer.
Temperature regulation: Shade provides shelter from the sun’s heat and infrared radiation, helping to prevent overheating and dehydration. This is especially important in hot climates.
Rest and relaxation: The shade provides a comfortable and cool space to rest, relax and protect yourself from excessive heat.
Shade considerations:
Balanced exposure: While shade is beneficial for protection from the sun, it is important to find a balance. Limited sun exposure is necessary for the synthesis of vitamin D in the skin, which is essential for bone and general health. Therefore, it is not advisable to always remain in the shade.
Hygiene and mental health: Adequate sun exposure is also important for mental health. Sunlight, particularly daylight, helps regulate circadian rhythms, improving mood and sleep quality. Spending time outdoors and enjoying natural light is beneficial for emotional well-being.
Additional Protection: Despite being in the shade, it is important to continue using sunscreen and protect your eyes with sunglasses, especially in areas with strong sunlight. Solar radiation can reflect off surfaces, such as water and sand, meaning that even in the shade, some UV radiation can reach the skin.
In short, shade is beneficial to health by providing protection from direct solar radiation and helping to regulate body temperature. However, it is important to find a balance and allow limited sun exposure for benefits such as vitamin D synthesis and regulation of circadian rhythms. The use of sunscreen and other care is still important even when you are in the shade in a sunny environment.
THE WALK-RWD SYSTEM
We have explained throughout the Blog, in the vast majority of the Posts, the great advantages that the WALK-RWD System has when practicing its 4 structured activities, considering that WALKING is the most important.
Receiving daylight, and not necessarily the direct rays of the Sun, also has all the advantages that we have mentioned in the previous paragraphs. Walking in daylight is not the same as walking inside the house or other covered spaces; although we have explained the advantages of walking at night as well (Posts THE WALK AND CIRCADIAN RHYTHMS-PART I; WALKING THROUGH STREET FORESHORTENINGS; Future Posts WALKING AT NIGHT. CIRCADIAN EFFECTS and THE WALK-RWD SYSTEM, ACCORDING TO THE TIME OF DAY AND NIGHT), so it is very convenient to schedule walks according to our free time (Free time: Post THE PROPER MANAGEMENT OF “SLACK TIME” IN THE DECISION TO WALK), to our own needs and characteristics, during the day (the most!) and at night (the least!).