After a class:

Improved Brain Function. 

Just 20 minutes of Hatha yoga -- an ancient form of the practice that emphasizes physical postures rather than flow or sequences -- can improve cognitive function, boosting focus and working memory. In a University of Illinois study, participants performed significantly better on tests of brain functioning after yoga, as compared to their performance after 20 minutes of vigorous aerobic exercise.

Lower Stress Levels. 

Yoga's stress-busting powers may come from its ability to lessen the activity of proteins that are known to play a role in inflammation, according to a study published last year from University of California, Los Angeles researchers.

Alter Gene Expression. 

A small Norwegian study suggested that yoga's many healthy benefits might come from its ability to alter gene expression in immune cells.

Increased Flexibility. 

A recent Colorado State University study found that Bikram yoga -- a form of yoga in which a series of 26 postures are performed for 90 minutes in a heated room -- is linked with increased shoulder, lower back and hamstring flexibility, as well as greater deadlift strength and decreased body fat, compared with a control group.

After a few months:

Lower Blood Pressure.

People with mild to moderate hypertension might benefit from a yoga practice, as a study from University of Pennsylvania researchers found that it could help to lower their blood pressure levels. Researchers found that people who practiced yoga had greater drops in blood pressure compared with those who participated in a walking/nutrition/weight counseling program.

Improved Lung Capacity.

A small 2000 Ball State University study found that practicing Hatha yoga for 15 weeks could significantly increase vital lung capacity, which is the maximum amount of air exhaled after taking a deep breath. Vital lung capacity is one of the components of lung capacity.

Improved Sexual Function.

A 2009 Harvard study published in the The Journal of Sexual Medicine showed that yoga could boost arousal, desire, orgasm and general sexual satisfaction for women. Yoga can also improve women's sex lives by helping them to become more familiar with their own bodies, according to a review of studies published in the Journal of Sex and Marital Therapy, as reported by CNN.

Reduced Chronic Neck Pain.

A German study published in The Journal of Pain showed that four weeks of practicing Iyengar yoga (a type of Hatha yoga that stresses proper alignment and the use of props) is effective in reducing pain intensity in adults suffering from chronic neck pain.

Anxiety Relief.

A 2010 Boston University study showed that 12 weeks of yoga could help to reduce anxiety and increase gamma-aminobutyric (GABA) levels in the brain (low levels of GABA have been linked with depression and anxiety disorders).

Relief from Chronic Back Pain.

Researchers at West Virginia University found Iyengar Yoga to be more effective in reducing pain and improving mood than standard medical treatment among those with chronic lower back problems.

Steady Blood Sugar Levels in People with Diabetes.

Adding yoga to a typical diabetes care regimen could result in steady blood sugar levels, according to a 2011 Diabetes Care study. Reuters reported that just three months of yoga in addition to diabetes care resulted in a decrease in body mass index, as well as no increases in blood sugar levels.

Improved Sense of Balance.

Practicing an Iyengar yoga program designed for older adults was found to improve balance and help prevent falls in women over 65, according to a 2008 Temple University study.

After a few years:

Stronger Bones.

A 2009 pilot study by Dr. Loren Fishman showed that practicing yoga could improve bone density among older adults.

"We did a bone mineral density (DEXA) scan, then we taught half of them the yoga, waited two years, and did another scan," Fishman previously told The Huffington Post. "And not only did these people not lose bone, they gained bone. The ones who didn't do the yoga lost a little bone, as you would expect."

Healthy Weight.

Researchers from the Fred Hutchinson Cancer Research Center in Seattle found an association between a regular yoga practice and decreased weight -- or at least a maintained weight -- among more than 15,000 healthy, middle-aged adults.

"Those practicing yoga who were overweight to start with lost about five pounds during the same time period those not practicing yoga gained 14 pounds," study researcher Alan Kristal, DPH, MPH, told WebMD.

Lower Risk Of Heart Disease. 

As part of a healthy lifestyle, yoga may lower cardiovascular risk factors such as high blood pressure, cholesterol and blood sugar, according to Harvard Health Publications.