Light therapy for weight loss: light therapy has many applications regarding weight loss. Near infrared-light can be used to help burn more fat. White light in the morning may help regulate the hormones leptin and ghrelin. Leptin is the hormone your fat tissues produce when eating to signal the brain that enough energy producing calories have been restored and you can stop eating. Ghrelin is the hormone produced in the stomach to signal the brain that you are hungry.
Red light is now being considered as “an innovative, non-invasive, easy to use, safe, and promising method for controlling obesity and abdominal fat” (1, pg.5). Near infrared light in wavelengths of 600-1000 nm wave lengths have been shown to be effective for weight lose.

In one study infrared light, at 850 nm at 100 mW, was shined on the thighs of postmenopausal women aged 50 to 60 years old as they walked on a treadmill (10). In this study a thermal imaging camera was used to record the activity in the fat cells of the skin the light was applied too. The active light group were compared to another, similar, group of women walking on a treadmill, but without light. The active or light group had a significantly higher body temperature then when they started exercising, as well as in comparison with the control group, who’s body temperature was lower than when they started exercising. This is because the exercise only group started sweating at about 10 minutes into the activity, and this cooled their skin. The active group also sweated, but the infrared light was absorbed by the water on their skin and then warmed it. Further, infrared light increased temperature as it improved the microcirculation via the vasodilator reflex, angiogenesis was also present (when new blood vessels form from pre-existing ones) (10). These reactions were probably due to the action of infrared LEDs on nitric oxide or NO. Here LED treatment, especially when combined with the contraction of skeletal muscles, leads to a thermal effect with higher circulation caused by a rise in muscle temperature can improve the supply of oxygen and the transportation and utilization of metabolic substrates (10).

Red light in the form of a near infrared (NIR) light emitting diode (LED) belt (NIR-7 Healthcare, Korea) with wavelengths of 700-960 nm worn on the abdomen during aerobic exercise can assist with weight loose. In a human trial of overweight adolescents, the subjects walked on a treadmill for 45 minutes per day, at a VOX max of 50%, three days per week. Half the subjects wore the belt with active lights, half wore inactive light belts. Those who wore the active light belts experienced an average reduction 0f 5.02% on their BMI (body mass index) score as well as a significant reduction, 5.65% (controls only lost .84%) in their waist circumference and overall 5.55 of body fat (controls lost none) (1). These findings echo other study results (1).
The reason red light therapy may work for weight loss lies in the effect it has on the production of energy within fat cells. The near infrared/red light, at a specific wavelength and wattage, penetrates the skin and surface fat to reach deeper adipose tissue. The tissue’s cells’ photoreceptor molecules absorb the light. In the molecules light improves cytochrome C oxidase’, which absorbs the light, functional activity, this then promotes mitochondria’s oxidative metabolism, all of which result in increased ATP production, and result in more energy availability for fatty tissues to be metabolized (1). In short, mitochondria, which is in cells, has cytochrome C oxidase, which absorb the light. The cytochrome experiences an acceleration in mitochondrial energy, leading to more energy being available for exercise and thus the improvement in calorie burning and body weight/fat reduction. Basically, in this study the belly fat became a fuel for ATP production, and this fuel was used during the aerobic exercise. Further, red light helps improve endurance during exercise, it delays fatigue and increases tolerance (1).

Regarding appetite related hormones ghrelin and leptin, it has been shown in studies on sleep deprivation that narrow band morning light exposure can modulate the production of these in people. When a person gets less than eight hours of sleep a night they usually produce more ghrelin (up to 28% more), and less leptin (up to 19% less). Ghrelin is produced in the stomach to signal hunger, and leptin is produced in the fat to signal satiety (fullness). In short, too little sleep leads to overeating. In animal studies melatonin has been known to decrease leptin concentrations, so it is possible that the subjects who were not getting enough sleep or morning light were experiencing an increased production of melatonin, or a disruption of the bodies ability to produce it at appropriate times. In short, using light (be it natural, white, blue, green, or red) in the morning significantly impacts sleep deprivation related hunger. Those sleeping five hours who were exposed to morning light, be it red (60 lux/6 nm), green (532 nm), or blue (475 nm), had significantly decreased concentrations of ghrelin and increased concentrations of leptin (22).

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This information is for educational purposes only. Please consult a qualified healthcare provider before trying anything mentioned above.