The Truth About 7 Big Yoga Claims

The myriad benefits attributed to yoga—weight-loss, heart disease protection, freedom from depression—are enough to get anyone on the mat, but do they hold up to modern scientific investigation? New York Times science writer and long-time yogi William J. Broad decided to find out. For his latest book, The Science of Yoga, Broad took a deep dive into the research to reveal which promises the ancient tradition can—and can’t—deliver on. “Yoga makes you feel good—every practitioner knows that. But the science is catching up to explain why,” he says.

Here's the real deal on seven big claims yoga makes:

Claim 1: Yoga Makes You Feel Good
True. One of the major reasons for yoga’s popularity—and perhaps why devotees are reluctant to critically assess the practice—is that yoga just makes people feel good.

Recent research is able to put that feeling in more technical terms. In 2005 a pair of comprehensive reviews of the research on yoga’s effects on anxiety and depression found that yoga helps moderate reactions to and perceptions of stress, as well as significantly lifting depression—especially for women. Yoga bumps up levels of the neurotransmitter GABA which both lifts mood and suppresses anxiety.

“Yoga calms everything down. It helps me remember to take a breath no matter what life throws at me,” says Heidi Kristoffer, certified yoga instructor at Strala Yoga in New York City.

Claim 2: Yoga is All the Cardio You Need
False. Anyone who’s ever left a yoga class soaked in sweat, breathing heavy, and walking funny the next day might find this hard to believe, but yoga doesn’t even meet minimum standards for aerobic exercise. In fact, even sun salutations, one of the more aerobically challenging yoga progressions, barely gets halfway to the American College of Sports Medicine’s baseline standard for aerobic exercise.

Claim 3: Yoga Can Help Prevent Heart Disease
True. Wait a minute. Yoga isn’t cardio, but it helps prevents heart disease? Sure does, just not the way you’d expect. While the exact mechanisms through which yoga helps aren’t understood, The Science of Yoga points to dozens of studies from around the world that show yoga lowers some of the most common risk factors for heart disease, including high blood pressure, high blood sugar, and atherosclerosis.