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 Exposure to bright light can lead to greater sexual satisfaction in men who have low sexual desire, a new study suggests. 
 
 Scientists from the University of Siena in Italy found that using a light box, similar to those used to treat some forms of depression, increased testosterone levels. 
 
 And this led to greater reported levels of sexual satisfaction. 
 
 But they said more research was needed before it could be used as a treatment. 
 
 The researchers carried out their study on 38 men who had been diagnosed with disorders which cause a lack of interest in sex. 
 
 Bright light 
 
 One half of the group was treated with a light box, while the other half was treated with an adapted light box which gave out significantly less light. 
 
 They were treated for half an hour early in the morning for two weeks. 
 
 When they retested the participants, they found that the group exposed to the bright light tripled their sexual satisfaction scores while the control group's scores stayed roughly the same. 
 
 The researchers also found that testosterone levels increased in men who had been given the active light treatment from around 2.1 ng/ml to 3.6 ng/ml - but the control group showed no increase. 
 
 Prof Andrea Fagiolini, who led the study, said the increased levels of testosterone explained the greater reported sexual satisfaction. 
 
 What is light box treatment? 
 
 Light therapy is where a special lamp called a light box is used to simulate exposure to sunlight. 
 
 A light box contains very bright fluorescent tubes - usually at least 10 times the intensity of household lights. 
 
 They are commonly used to treat Seasonal Affective Disorder. 
 
 A patient looks into the light box and when light hits the back of the eye, messages are passed to the part of the brain that controls sleep, appetite, sex drive, temperature, mood and activity. 
 
 Some people seem to need a lot more light than others for their body to function normally. 
 
 Mimics nature 
 
 And he went on to explain how the light box treatment works. 
 
 He said: "In the northern hemisphere, the body's testosterone production naturally declines from November through until April and then rises steadily through the spring and summer with a peak in October. 
 
 "You see the effect of this in reproductive rates, with the month of June showing the highest rate of conception. The use of the light box really mimics what nature does." 
 
 Prof Fagiolini said he thought the light therapy inhibited the pineal gland in the centre of the brain, which allowed more testosterone to be produced. 
 
 Future hope 
 
 There are several possible reasons for lack of sexual desire and treatment depends on the underlying cause. 
 
 It can be treated with testosterone injections, antidepressants, and other medications. 
 
 The researchers believe that light therapy in the future may offer the benefits of medication, but with fewer side effects. 
 
 But he said they were not yet at the stage where they could recommend it as a clinical treatment. 
 
 The paper will be presented at the European College of Neuropsychopharmacology (ECNP) Congress in Vienna. ||||| Low sex drive? Try exercising less, study says 
 
 Intense exercise might give you a lean physique, but it could potentially slow down your sex drive, suggests a new study published this month by researchers at UNC Chapel Hill. 
 
 Previous studies have typically measured hormone levels in men, data which is easy to measure quantitatively. These scientists, however, put down their probes and asked men to talk about sex. 
 
 The researchers began by distributing a questionnaire to 1,100 physically active men that asked them how often they engaged in and thought about sex. A separate questionnaire probed participants' exercise habits. 
 
 Upon crunching the numbers, the scientists concluded that participants with the lowest and mid-range training intensities were more likely to have a high/normal libido. The researchers also found that participants who trained for shorter and mid-range durations had greater odds of a high/normal libido score than those who exercised for a long period of time. 
 
 The sample of men voluntarily elected to complete the survey, so the study hardly represents all men. Additionally, the data does not confirm that excessive exercise causes low libido, only that the two are linked. 
 
 Anthony Hackney, who led the study, told the New York Times that physical fatigue and lower testosterone levels associated with exercise likely account for dampened libidos. 
 
 Hackney's research stands out as one of the few studies that looks at men's exercise and its far-reaching impacts. Past studies have tended to look at hormonal imbalances in women. 
 
 This latest study hopes to add men to the conversation. 
 
 "Fertility specialists will often ask a woman about whether and how much she exercises," Hackney told the New York Times. "Based on our data, we think they should also be asking the man." 
 
 Read Michelle Robertson’s latest stories and send her news tips at mrobertson@sfchronicle.com.
– Men with low sex drive might try switching on a light, a new study shows. Taking a cue from depression treatment, researchers at the University of Siena in Italy found that bright light stimulates testosterone levels and led to better results in the bedroom, reports the BBC. Using a light box lined with fluorescent tubes, researchers tested the effects on 38 men diagnosed with low libidos. One half were exposed to bright lights, and the rest to lower doses of light. Those who received the brighter lights for 30 minutes daily over two weeks tripled their rate of sexual satisfaction.The amount of testosterone in the control group didn't change, but the bright-light group saw their levels rise to 3.6 nanograms per milliliter from 2.1. "The increased levels of testosterone explain the greater reported sexual satisfaction," said lead author Andrea Fagiolini, per the Independent. He said testosterone production among men in the northern hemisphere declines naturally from November through April (peaking in October). "The use of the light box really mimics what nature does," Fagiolini said. He said light therapy "inhibits the pineal gland in the center of the brain and this may allow the production of more testosterone, and there are probably other hormonal effects." Light box therapy is commonly used to treat depression caused by Seasonal Affective Disorder. Although researchers cautioned that more research was needed, light therapy could be a promising hope for men whose sex drive is off, particularly during the winter months. A quarter of men over 40 report lagging libido and other problems, reports the Independent. (Women with low libido should check their heart rate.)