Light and Darkness -
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As daylight patterns shift from the light of receding summer to the darkness of approaching winter, we become more conscious of the waxing and waning of light and darkness. Light and darkness affect your mood, energy levels, weight, hormone levels, sexuality, fertility, and even your life span. Light and darkness are vital to your mental, emotional, physical and spiritual health and wellbeing. You need both light and darkness and you need them in a regular pattern if you are to be more connected to your self by your natural rhythms.
We receive light through our eyes. They gather information about shape, color, intensity of light, timing of day and night and relay this information to the brain. We also receive light through our skin, which absorbs light and allows certain wavelengths to penetrate.
Bright natural outdoor light stimulates your pineal glad to make serotonin. Serotonin is an important "feel good" neurotransmitter. Serotonin regulates your feelings of well being and satisfaction. (Read Top Ten Signs That Your Serotonin Levels Are Too Low.) Without adequate levels of serotonin, you may fall into depression.
As the daylight dims, the pineal gland produces less serotonin. And once darkness arrives, it stops releasing serotonin and begins producing melatonin. Melatonin helps to control your biorhythms by controlling the body clock, regulating your sleep/wake cycle, helping you sleep soundly, lowering your blood pressure, influencing sexuality and fertility, boosting immunity, and acting as an antioxidant. Due to its powerful antioxidant properties, healthy melatonin levels are implicated in preventing premature deaths due to heart attacks, cancer, and rapid aging.
At dawn, the approaching light signals the pineal gland to stop making melatonin (melatonin production ceases at only 200-300 lux very dim light) and to begin again the production of serotonin. As daylight brightens and you are exposed to the natural light, the pineal gland makes more and more serotonin.
Exposure to normal day/light night/darkness cycles entrain your body clock to its normal rhythm. The body clock influences almost 200 processes in the body including those that effect hunger, energy, blood pressure, body temperature, digestion, physical strength, reaction times, sexual appetite, urine production and brain balance. Without the exposure to normal light /dark cycles, the body clock can go awry and your internal rhythms and physiology can become chaotic.
Daily exposure to light and darkness influences sexuality and fertility and keeps hormones in balance. Sunlight boosts testosterone a hormone important in increasing sexual desire - in both men and women. (Light shone directly on a mans scrotum raises testosterone levels more than light shone elsewhere.) Sunlight also boosts estrogen levels, which are needed for vaginal integrity and lubrication. A lack of light seems to reduce fertility and may negatively effect the ability to conceive.
In addition to the pituitary gland, natural light stimulates the hypothalamus and thereby influences the level of almost every hormone in the body. Natural light sends messages to the hypothalamus through the eyes and smaller amounts come through the skull. The hypothalamus balances actions of the autonomic nervous system-which runs the basic body functions. This affects the heart rate, digestion, blood pressure, temperature control, appetite and thirst, fluid balance, stress level, emotions and immunity. The hypothalamus also uses information about light to balance its production of hormones that trigger the release of pituitary hormones such as melanocytestimulating hormone, prolactin, endorphins, and hormones which regulate the thyroid, adrenal glands, ovaries and testes.
Because of its effect on the hypothalamus and the pituitary gland, light has been suggested as an effective part of therapy for hormone imbalances such as premenstrual syndrome, thyroid imbalances, polycystic ovaries, and infertility.
The limbic system uses messages about light to help regulate the bodys production of adrenaline and noradrenaline and to influence emotions.
When your skin is exposed to light, it increases the production of antiseptic oils that encourage wound healing. The light exposure on the skin helps lower cholesterol levels and helps produce Vitamin D and testosterone. Light - ultra-violet B - exposure on the skin promotes the production of Vitamin D from cholesterol. Vitamin D is a hormone that is in serious short supply in many people today. Vitamin D affects the health of your bones, brain, breasts, prostate, stomach, colon, pancreas, parathyroid glands, skin, and bone marrow. Vitamin D also decreases muscle weakness and pain, prevents rickets in children, helps prevent osteomalacia and osteoporosis in adults, helps prevent tooth decay, reduces blood pressure, lowers cholesterol, lowers blood sugar levels, and reduces insulin resistance. Vitamin D regulates normal cell division and some studies suggest that it reduces the incidence of certain cancers.
Some of the light that hits your skin penetrates very deeply and produces heat in the body. This makes your arteries and veins expand - increasing the supply of oxygenated blood. The blood distributes some of the energy from light on the skin to every part of the body. Light on your skin influences your immunity, guards against certain skin infections and even reaches the brains body clock.
Fat loss may be significantly affected by your exposure to sunlight. Bright sunlight is essential to increased energy and metabolism and fat loss. Optimal exposure to light raises your metabolism and spending the day in low light stimulates fat storage. When the skin is exposed to sunlight, it triggers the production of melanocortin. When melanocortin reaches the brain, it suppresses the appetite centers, which speeds up metabolism and promotes fat loss. Melanocortin also stimulates thyroid hormone production, which increases metabolism.
Vitamin D may also be an important factor in weight control. Vitamin D is related to calcium absorption. When there is too little Vitamin D too little calcium may be absorbed. A low calcium level signals the release of calcitrol, which turns off the mechanisms that break down fat and burns it. Calcitrol also activates the mechanisms that make body fat. Light exposure may help elevate metabolism and help normalize weight.
While it is possible to make up for lack of exposure to bright natural light, indoor lighting generally is not bright enough to regulate the necessary effects on your hormones and neurotransmitters. Brightness is measured in lux - with 1 lux being the equivalent of the light from 1 standard candle. Living room light in the evening is about 100 lux with a well-lit room reaching up to 500 lux. Bright indoor light might reach up to 700 lux.
Compare that to natural lighting. Outdoor light at twilight is around 100 lux, a cloudy, rainy day around 2,000 lux, a sunny spring morning around 10,000 lux, a summer day around 60,000 lux and noon on a bright sunny day up to 100,000 lux.
Take Home Message
A lack of exposure to the natural light /darkness cycles can result in hormone and neurotransmitter imbalances, disturb the way the brain responds to neurotransmitters and upset the body clock. You need daily, rhythmic exposure to both natural daylight and to nightly darkness.
Get outside in natural daylight. Spend 20 30 minutes outside in the morning when you first wake. This has powerful healing effects for your body clock and natural rhythms. As often as you can, spend at least 2 hours outside in natural daylight.
Tips and Precautions
In the evening keep the lights low or dimmed. Bright lights interfere with raising melatonin levels (the hormone needed in good supply for a good nights sleep and more).
Sleep in the dark. Women, especially, need to sleep in the dark without a night-light. Exposure to light at night reduces your production of melatonin (a key hormonal, immune and body synchronization hormone) and interferes with proper immune and hormonal production. If you can see your hand at night with the lights out there is too much light for proper hormonal production. And if you can see your hand in front of your face at night with all the lights turned off there is too much light for good quality sleep. A sleep mask can be a great aid. You may also find it helpful to draw your curtains or use heavy covering for windows that are exposed to artificial street lighting at night.
© Copyright 1997 - 2008 by Mary Ann Copson and Evenstar. All rights reserved.
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