Cold and flu season is approaching, and these retreats focus on wellness. From meditation to yoga and massages, here's what spas and resorts are offering to promote health among corporate groups.

The Ritz-Carlton Spa in Los Angeles is available for full-day buyouts. The venue can hold 20 guests a time and typically offers 25-minute services during private events. The spa can also offer healthy lunches, meditation, and a physical activity such as yoga.

Located in the Finger Lakes region of New York, Inns of Aurora hosts a restorative retreat at its historic Rowland House. Open to corporate groups of 20, the retreats include restorative yoga, workshops in essential oils, massages, nature walks, and fireside wellness talks.

In Santa Monica, California, Hotel Casa del Mar offers private sessions in AIRR (Automatic Integrative Relaxation Response). The sessions focus on alleviating stress and developing tools to deal with daily life challenges. The founder of the program, John Sahakian, can customize sessions to different groups' wellness goals or lead short seminars before meetings or work with groups during daylong retreats. The sessions, which include practicing breathing and relaxation techniques, can take place in meeting rooms or on the beach and can accommodate 10 to 30 guests.

Southern California's Terranea Resort provides customized wellness retreats for corporate groups. The resort has a 50,000-square-foot spa and fitness and wellness centers. Retreats can include private fitness classes such as oceanfront yoga, trail hikes, consultations with a nutritionist, and spa treatments such as massages or facials.

The St. Regis Aspen Resort in Colorado hosts a three-day "Mountaintop Reboot" program. Guests participate in activities such as fat biking (or biking through the snow), yoga, and massages; they also get healthy refreshments such as cold-pressed juices. The program is available through April 17 and can be customized to groups.

In Scottsdale, Arizona, the Sanctuary on Camelback Mountain has customized group wellness programs. The programs can incorporate swimming, spa treatments, hiking, triathlon training, and an activity called "Zennis," which blends yoga and tennis. The retreats are customized to individual groups and can be easily adapted to suit different numbers of guests. For more one-on-one time with the fitness instructors, though, staffers recommend keeping group sizes to 10 to 12 guests. Starting in 2016, corporate groups can rent out the resort's new Spa House, which will host meditation retreats and offer a private pool, sauna, workout studio, and tennis court.

The Mandarin Oriental Hotel spas—including the Las Vegas Location—have a Wellness in Travel Platform. Designed to relieve stress in groups and make guests more alert in meetings, the platform incorporates services based on Traditional Chinese Medicine. The spa also hosts custom half- and full-day activities for groups, and programs can include personal training, yoga, Pilates, spa lunches, and lounging in the Hammam (pictured).