While massage may have developed a reputation as a decadent treat for people who love pampering, new studies are showing it has a wide variety of tangible health benefits.

Research over the past couple of years has found that massage therapy boosts immune function in women with breast cancer, improves symptoms in children with asthma, and increases grip strength in patients with carpal tunnel syndrome. Giving massages to the littlest patients, premature babies, helped in the crucial task of gaining weight.

The...