Yup. I've seen the effects in my own family -- not only immediate family members for whom I've been a caregiver, but extended family.

That's one of the main reasons I try to get out and at least walk every day, and ride my bike even when I'm not really feeling well. I wake up aching all over every day, but have some coffee and ibuprofen and finally decide I can't possibly be any more miserable walking or riding the bike, so I might as well get out there and move the body. I almost always feel better once I get going.

Folks who think exercise is too much effort and a burden aren't thinking about how much effort and burden they're shifting to other people -- often family members -- to care for them as they deteriorate from years of being sedentary.

I watched my mom go through this for years, doing less and less, walking less and less, using her power wheelchair more and more, until she had no strength in her arms and legs. Like my granddad, she resisted physical therapy from visiting therapists. Eventually she could hardly get up from the sofa or chair or bed. Then osteoporosis worsened from lack of exercise and her femur just snapped spontaneously while walking at home. Now she's in a nursing home because her condition demands 24/7 care, beyond what Medicare/Medicaid will cover in home care.

In contrast my family and extended group of friends included women who remained as active as possible well into their 80s and 90s -- one even lived to 102, although she slowed down after age 100, the last year she attended the opera with us. They walked, puttered around the house instead of parking on the sofa or bed all day. One still bowls. They've slowed down a bit, but had remarkably full lives much later than some folks who became sedentary at middle age and declined rapidly.