I am paraphrasing from memory (I didn't get a chance to write this earlier) but he says exercise is good and people should do it regularly (5 days per week). No arguement so far. But, he goes on to say that you should perform 30-60 minutes of aerobic exercise, of which some should be weight-bearing (like walking as opposed to swimming). However, strength training shouldn't be pursued too much because weight lifters muscles are overdeveloped! Ok, a couple deep breathes and I will start my rant.
I need to preface this rant by saying Mr. Buettener is not the only one spouting this nonsense. Other so-called 'health experts' do too, showing their personal biases. But, he just is the latest to spout this nonsensical advice.
Let me get this right, you should not pursue one of the few activities that has been continually supported by scientific research to be able to positively influence your physiology, reverse the effects of aging, and enhance your functional capacity? Aerobic exercise does improve health and is associated with longevity, but it has several limitations that strength training doesn't. You are not going to reverse or prevent muscular weakness, sarcopenia (muscle loss due to aging) or osteoporosis with aerobic exercise. Even the 'weight-bearing' exercises like walking and running don't load the musculoskeletal system enough to provide an adequate stimulus to build up these tissues. Ironically, when I worked in cardiac rehab, the limiting factor for most patients was not their cardiopulmonary status, but their strength; balance, and joint health.
One of the limitations to even performing aerobic exercise is joint health. So, activities like walking and running generally have to be abandoned or curtailed after several decades. Degenerative changes in the joints are one of the primary obstacles we face with aging and often take away our independence. How many joint replacement surgeries are performed each year? Strength training is one of the few activities that will improve or maintain the active (muscles crossing the joint) and passive (ligaments and cartilage) components of joints.
I am sure the 95 year-old Jack Lalanne would agree with me!