Putting group fitness classes in the proper light NEW YORK (Reuters) - Fitness experts are shining a new light on group classes from Zumba to yoga because they believe the right lighting can transform the four walls of a fitness studio from a dance party to a meditation space, and back again. "Because of the theatrical nature of group fitness classes, lighting is key to differentiate programming," said Donna Cyrus, senior vice president of programming at Crunch fitness centers. Yellow or orange light boosts high-energy workouts, such as rebounding mini trampoline routines, circuit classes or sculpt programs, Cyrus said, while for yoga the light should be soft and soothing. Lighting also enhances the musical experience, Cyrus said. In a cycling class, accents of "club type" lighting pulse to the beat of the music, creating what she calls "a choreographed show." According to the American College of Sports Medicine (ACSM) guidelines, adjustable light sources should be provided in group exercise areas. Generally, the more hand-eye coordination an activity demands, the more illumination is required, according to Grace DeSimone, national director of group fitness at Plus One Health Management, which designs and manages fitness centers for corporations, hotels and community centers. "If you're going to be moving around a lot you'll need a lot of light," DeSimone said. You're not going to do a boot camp workout in a dark room. But indoor cycling classes often combine high energy and low lighting. "Spinning goes against the grain," DeSimone explained. You can do some pretty cool things - make the room look like a night-time sky or light a disco ball - because once you're on that bike you're not going anywhere. In a multi-purpose fitness room, she said, the lighting has to be able to change based on what's going on. "With Pilates you want the lights on, but with yoga you can do a lot with colored lights," she said. One reason light affects mood and alertness is that it cuts down on the sleep-inducing hormone melatonin, said Gregory Chertok, a sport psychology consultant for ACSM. "In a dark room, the brain secretes melatonin," he explained. Chertok, the director of mental training at The Physical Medicine & Rehabilitation Center in Englewood, New Jersey, said studies of factory workers have found that rooms with greater lighting will often yield greater productivity. He also cited research that found some blue lighting, which is favored in some yoga and meditation classes, can be even more effective than white fluorescent light in suppressing melatonin. "Sustaining blue-enriched light seems to help with concentrating on something for a long period," he said. ACSM guidelines suggest efforts should be made to use natural light. "We like to feel the sun," Chertok said, "so it's natural for gyms to try to simulate that." Daylight not only brightens a room, he suggests, it conveys information. "Perhaps daylight and natural lighting provide gym-goers with accurate weather and time information, which may be helpful in planning the length and duration of the workout," he said. Chertok said research has demonstrated that the mind is generally sharper during daylight hours. "A study in the late '90s found that even sleep-deprived people were sharper during the daylight hours," he said, adding that in another study, students in schools with natural lighting did better on performance tests. Darkness, Chertok said, is more associated with letting go. "Think of restaurants," he said. Darkness can contribute to ordering more. Editing by Patricia Reaney