Meditation, a cornerstone of Eastern philosophy and a part of American culture since the 1960s, has developed into a major business enterprise. Supported by an increasing number of scientific research papers quantifying its effects, meditation, often called mindfulness, generated $1.2 billion in revenue last year. Four in 10 adults in the United States say they meditate at least weekly, and major companies including Google, Apple, General Mills, Goldman Sachs and Aetna have adopted meditation programs for their employees. The industry has attracted $260 million in investments since 2012.Key takeaways: Health insurance giant Aetna reported that employees’ annual productivity rose by about $3,000 each after they participated in a mindfulness training program. Headspace, the largest of nearly 1,000 mindfulness apps, raised $36.7 million in funding in 2017. The company offers in-flight meditation channels on eight airlines and released plans for public, phone booth-sized relaxation “pods.” Experts say the industry’s growth raises concerns about the need for credentialing. Founders of new, for-profit mindfulness services say they are modernizing ancient teachings to make them accessible to the general public.