New York Times health columnist, Jane Brody, did for health club membership and the careers of personal trainers what no amount of advertising and promotion could. But she also did all of us a favor when she declared that a 30 minute walk several times a week just won’t cut it if you intend to remain fit and healthy throughout your life.

This is also the message of a book that we’ve been reading: Younger Next Year: A Guide to Living Like 50 Until You’re 80 and Beyond, written by 70-something Chris Crowley and his doctor, 40ish Henry S. Lodge. This quote from the inside flap is representative of the plain spoken style of the authors: Exercise tells the body to grow. Sitting too long tells the body to decay. The bottom line: vigorous aerobic exercise, particularly in the second half of life, is not optional. It is the key to making sure our health span equals our life span.

As a yoga teacher, I do have one important caveat about ramping up your fitness level: Don’t rush it. If your preferred form of exercise has been surfing the Internet, take some time to work up to a fitness level that makes sense for your body type and capability. And to avoid Boomeritis, the term for the epidemic of bone and joint aches, pains, and injuries, coined by orthopedic surgeon, Dr. Nicholas DiNubile, make sure you are approaching the heavy duty stuff like working with weights in a mindful way, and that you are balancing it with plenty of stretching and warmups.

Maybe because I have been thinking about this a lot, I attracted two new students to my Gentle Yoga class this morning. They were self-proclaimed gym-rats, 50+, muscular, part of the iron-pumping crowd that fills the gym where I teach yoga twice a week. I was particularly delighted to see these two body-builders in my class because I believe yoga can prevent or alleviate Boomeritis.

First off, one of the principles of yoga is ahimsa, non-violence, including violence to yourself. Second, yoga encourages you to focus on your breath and the subtle sensations of the body. Training one’s awareness, the heart of this body/mind discipline, reduces the likelihood of doing something dumb. Third, yoga is — or should be — very gradual. Even an advanced class begins with easier, almost intuitive stretches and moves, then progresses to deeper, more challenging work. Simply, yoga is ideal for the older body. Due diligence note: check with your physician before you begin any form of exercise.

Speaking of health, did you know annual cost of health care is a record-breaking $2 trillion? Listen to this NPR report about an unusual group of partners — AARP among them — who are launching a grassroots campaign for universal access to affordable health care.