Falls are the leading cause of fatal and nonfatal injuries among older adults — even those who are fit and active. Each year, 1 in 4 Americans over 65 years old fall, resulting in more than 32,000 deaths, according to the Centers for Disease Control.

"There are a lot of different things that go on as people get older — the muscle mass tends to decrease; processing time is longer; the ability of the nerves and joints to sense where the body is in space becomes less effective and the vestibular system that controls balance in the inner ear gets less sensitive and less able to do its job," said Jessica Davidson, an internist at the Palo Alto Medical Foundation and former medical director at Channing House retirement community in Palo Alto. "You can't fix what's happening in the body, but what you can do is compensate for those things."

Davidson and other local experts shared prevention tips to help older adults reduce their risk of falls.

Davidson recommends getting as much exercise as possible.

"If you have less muscle mass, then you want the muscles you do have to be as strong as possible," Davidson said "If you don't have the greatest native balance because of your vestibular system, you can actually exercise and train your vestibular system so it gets used to more movement and more challenges, so it knows what to do with them."

She said a number of researchers conducted balance studies, and tai chi was the one exercise that consistently came out with the best result.

Any increased movement is good, she added.

"Everybody should get as much exercise as they can as many days of the week as they can, even if it's a 20-minute walk," she said. "When we get older people tend to reduce their sphere of movement, or the range of movements they make, so at a certain age we're really just standing, sitting, walking or lying down. Instead of playing tennis, we sit down and do a puzzle. Once you're not in the habit of reaching out or stretching very far, these activities become difficult — you're stiffer, you have less flexibility and you're less able to be active in the moment."

Besides general exercise, Davidson recommends that older people practice shifting their balance and doing some reaching and larger stepping than they're used to. (Do it under supervision or while holding onto something, she cautioned.)

"In my class at Channing House, I had people playing a kind of baseball using pool noodles, swinging at a beach ball, or they'd walk next to each other tossing a beach ball back and forth."

Michelle Nguyen, a specialist in orthopedic physical therapy at PT Works in Los Altos, said a majority of falls happen as people age because of an interaction of risk factors, including a decline in mobility, cognitive and visual impairments and medications, as well as environmental hazards, such as rugs, pets and poor lighting. Fear of falling is another risk factor, she said.

In addition to reducing environmental and medical risk factors, Nguyen suggests improving one's strength, balance and mobility deficits.

"Being able to work on general fitness has been found to decrease the risk of falls — things like tai chi, yoga and general fitness," she said.

Nguyen said her go-to exercises are usually some sort of calf stretch that covers the flexibility component. Heel raises — going up and down on the toes — is the strengthening component.

"I'm a big fan of practicing standing up and sitting down from a chair, with or without hands. It's safe and it's practical," she said.

In the physical therapy setting, Nguyen identifies goals that are specific to each patient. She determines whether a person needs to work on core strength and hip strength, or should focus on things like static or dynamic balance.

"So much of what we do in life is somewhat repetitive and fairly sedentary, so I've always viewed exercise as your chance to mix it up," she said. "Our bodies move in so many different ways, and we often don't take advantage of that. And that gets much more exaggerated as we age and blends into this fall risk. All of this requires time and effort and practice."

Yoga teacher Lily Anne Hillis emphasizes that muscle memory is what keeps people from falling down.

"Say you trip and lose your balance; thinking does not work because there's not enough time to think before you hit the pavement," explained Hillis, 85, who has been teaching yoga for 35 years. "You need to rely on your instinctual reaction, which you only get from practice, and you need to practice enough so that what you get is muscle memory."

Hillis said the bottom of each foot has 25,000 nerve endings — 50,000 in all — and those nerve endings are talking to your brain constantly.

"From that interaction comes proprioception — your sense of where you are in space. It's all unconscious," she said. "You don't have to do anything. It's happening in the bottom of your feet, and that's why I like to teach people in bare feet."

Hillis said the best way to develop muscle memory is to challenge yourself.

"If you have a pose, and you're perfect in it, you want to challenge yourself to become out of balance and allow your nerve endings to bring you back into balance," she said. "You want to put yourself into positions where — with a teacher — you will challenge your balance enough to get wobbly so that you're retraining your brain."

She suggests a simple way to start is to stand with your feet apart, relax your knees and shift from side to side. Then lift the opposite leg and move from heel to toe, toe to heel, keeping your head over your pelvis while looking at the horizon, not at the ground.

"The more you do weight shifting, the more the bottoms of your feet will talk to your brain and your brain will remember how to bring you back if you start to fall," she said.