Perhaps it’s a testament to the power of yoga that so many spin-offs have emerged—dozens since it originated some 6,000 years ago. There’s laughter yoga, which turns humor into a healing power, AcroYoga, which revolves around flying, and hot yoga, taught in a 105-degree studio. Even naked yoga is catching on, described by followers as a therapeutic way to burst out of the confines of clothing.

Research bolsters the claims made for the trend: Yoga protects the brain from depression, an August study found; three sessions per week boosted participants’ levels of the brain chemical GABA, which typically translates into improved mood and decreased anxiety. “People who have disorders like depression and anxiety can definitely benefit from yoga, because it returns [GABA] levels to the normal range,” says study author Chris Streeter, an assistant professor of psychiatry and neurology at Boston University School of Medicine. Streeter says yoga can be used to complement—not substitute—drug treatment for depression.

Past research has explored yoga’s effect on epilepsy, heart disease, cancer, and multiple sclerosis, among other conditions. A 2004 Yale University School of Medicine study, for instance, found that people who practice yoga reduced their blood pressure, pulse, and risk of heart disease. The health benefits likely come about — at least in large part — because yoga helps people better manage stress, says Janice Kiecolt-Glaser, a professor with the Institute for Behavioral Medicine Research at Ohio State University College of Medicine. “Yoga has a meditation component that is not true of other exercise. That aspect makes a difference,” she says.

Other reasons to give the “warrior” or “downward-facing dog” poses a try: Yoga can increase strength, endurance, balance, and flexibility. Some types, like Ashtanga, are even vigorous enough to count as cardio workouts. Which type is most beneficial? “That depends on each individual person,” says Streeter. What eases one person’s back pain may do nothing for another. Below is a look at some of the more popular yoga varieties, what they involve, and their purported health benefits. Kathy White, who has studied Kaiut Yoga and several other yoga varieties, believes there can be a positive aspect in combining elements of different forms of yoga.

Ashtanga yoga

The fitter you are, the more likely you’ll enjoy Ashtanga yoga, which revolves around repetition of athletic poses and leaves almost no time for catching your breath. The vigorous sessions involve standing and seated poses, back bends, and inversions—holding the head below the heart. You won’t build bulky muscles, but you will increase muscle density. “Advanced practitioners look like Olympic athletes,” says Lori Brungard, who teaches Ashtanga in New York City. “It’s a very intense form of yoga, and because it’s so demanding, it does require consistent, steady, regular practice to see the benefits.” She recommends five to seven hour-long sessions per week.

AcroYoga

If yoga married gymnastics and circus art, you’d get this gravity-defying breed. First practiced in San Francisco six years ago, AcroYoga has seven elements, including Thai massage, therapeutic flying, and partner acrobatics. One person, the base, lies on the ground and uses his arms and legs to support a flyer. While suspended, the flyer twists into a series of positions—including the “folded leaf,” hanging upside down on the feet of your partner. AcroYoga tones and loosens: “It’s really great for people with back problems—you’re opening your body without strain and without forcing it, and with the support of another person,” says Vanessa King, a Washington, D.C.-based AcroYoga instructor. “You go from a Thai massage to the greatest activity of being lit up and energized in an acrobatic pose.”

Iyengar yoga

Nicknamed “furniture yoga,” Iyengar incorporates props like blankets, blocks, straps, harnesses, and incline boards—all in the name of helping you bend into a more perfect position. An August study published in the journal Cancer Nursing found that women in treatment for or recovering from breast cancer benefited from Iyengar classes. More than 90 percent said Iyengar improved their quality of life, 88 percent felt better physically, and 80 percent were less tired. People who are stiff, immobile, injured, or ill can use the props and the support, and it improves their stamina, strength, flexibility, and confidence.

Bikram yoga

Followers call it “hot yoga,” because studio heat is cranked up to 105 degrees with 60 percent humidity — even in the summer. The 90-minute sessions revolve around a series of 26 postures, each performed twice. There are “spine twisting” and “toe stand” poses, for instance, and a “cobra pose”—legs and pelvis on the mat, back arched, and torso erect. Expect to burn between 350 and 600 calories in one class, while building stamina and endurance. Heat warms the muscles, allowing greater flexibility, says Kelly Schrader, who owns a Bikram studio in Grass Valley, Calif. “It’s tremendously beneficial—especially for people who have joint injuries, inflammation, or conditions like arthritis,” she says.

“It boosts your overall health and immunity.” Some advocates say hot yoga also helps flush toxins from the body, but doctors generally believe the body is more than capable of ridding itself of most harmful and waste products on its own. Prolonged time in a hot environment raises the risk of fainting and can be dangerous to those susceptible to heatstroke, like pregnant women, young children, and the elderly. If you’re concerned, talk with your doctor before trying a class. And make sure to drink water frequently, while watching for nausea, dizziness, and the absence of sweat, which suggests dehydration. You’ll find more on Bikram and other yoga varieties at this chicagotribune.com article.

Naked yoga

While doing yoga au naturel may not offer unique physical health benefits, practitioners say it’s good for the soul. Aside from the liberated thrill of baring it all, it’s considered a way to work toward accepting your own body. Naked yoga is not a sexual experience. At the studio Naked Yoga NYC, for example, removing clothing is a ceremonial process that happens at the start of each class, and nudity—contained to one room—is not permitted in any other part of the building. Proper hygiene is required; participants must come freshly showered.

Laughter yoga

Those who believe that laughter is the best medicine may want to give this a try: Laughter yoga blends attempts to provoke laughter via eye contact and childlike playfulness with breathing exercises. “The idea is that if you’re laughing on the outside—even if, initially, you’re faking it—it will create an effect on the inside that brings joy and releases endorphins,” says Mary-Laurence Bevington, director of Movement Climbing & Fitness in Boulder, Colo. Indeed, research suggests that laughing generates feel-good hormones while lowering levels of the stress hormone cortisol, and that it boosts the immune system, improves blood flow, and increases oxygen intake, which replenishes and invigorates the body’s cells. Laughter yoga has been introduced into senior centers, cancer wards, corporations, and prisons.

Koga

This kickboxing-yoga hybrid works every muscle in the body. Koga involves kicking, throwing punches, assuming fighting stances, and bending into yoga positions. At the end of each set, participants do a yoga pose that coincides with the muscle group they just worked, enhancing the effect. Expect to burn between 800 and 1,200 calories per each one-hour class, according to Koga’s creator, Jon Koga. Koga is making its way into school PE programs, and some classes cater to the 65 and older set, who perform movements while seated in chairs.