Seniors who lifted weights or did other forms of resistance training slowed their decline to full-blown dementia, a study including B.C. researchers has found.

A six-month strength training program that targeted women with mild cognitive impairment and complained of memory problems helped improve their attention, problem-solving and decision-making brain functions — all needed to live independently.

Resistance training improved the function of brain areas that support decision-making, researchers found. (Andres Stapff/Reuters)

In the study, 86 women 70 to 80 years old were randomly assigned to three groups:

26 participants did resistance training, such as lifting weights, to build muscle strength.

24 walked outdoors in an aerobics program.

27 took basic balance and toning classes as a control.

The exercise classes were held twice weekly.

"What our results show is that resistance training can indeed improve both your cognitive performance and your brain function," said Prof. Teresa Liu-Ambrose, who led the study at the University of British Columbia.

"What is key is that it will improve two processes that are highly sensitive to the effects of aging and neurodegeneration: executive function and associative memory — often impaired in early stages of Alzheimer's disease."

Brain, body strengthened

Resistance training to work specific muscle groups is an important aspect of fitness, helping increase muscle mass and slow down or halt muscle loss, slow bone loss, and maintain or increase joint flexibility.

In the case of the B.C. research, the resistance training program improved associative memory, which refers to the ability of one thought or memory to trigger another, like "green means go," as well as conflict resolution.

Almost one-third had functional MRIs at the start and end of the study to look for brain activity changes.

After six months, compared to those in the balance and tone classes, the strength-training group showed "significant" cognitive improvement, the researchers said in this week's issue of the Archives of Internal Medicine.

Those in the strength-training group also showed changes in activity in specific parts of the brain's cortex that are associated with cognitive behaviour.

The investigators prepared a YouTube video to guide seniors and fitness instructors working with older people on how to start doing simple exercises at home or at the gym.

These exercises include squats — a lower-body exercise that involves standing with feet about shoulder-width apart, lowering the body into a squat position and moving back up to standing position, then repeating the up-and-down movement.

Use it or lose it

The researchers advised seniors new to exercising to use a trainer to ensure they're doing the exercises with proper form and to build up from there.

The study included a small number of subjects, and needs to be repeated in a larger group to confirm the value of resistance training in seniors and test for longer-term benefits.

As for why those in the aerobic training group didn't show the same improvements, Liu-Ambrose speculated that the mental power needed to learn the resistance routines could be playing a role, compared with walking, which tends to come more naturally.

"Strength training itself is a type of exercise that requires a lot of attention," she said in an interview.

"So when you are performing strength-training exercises such as lifting weights, you're constantly monitoring what you're doing, you're monitoring your breathing, you're trying to monitor the number of sets, the repetitions you're doing as well as maintaining good form."

Two participants had short-term shortness of breath and four fell without injuring themselves.

Earlier studies in healthy older adults without mild cognitive impairment suggested that aerobic training helps cognition and brain plasticity.

The study also included investigators from the psychology department and division of geriatric medicine at UBC, and the psychology department at the University of Iowa.

The studies were funded by Pacific Alzheimer's Research Foundation and infrastructure support from the Canada Foundation for Innovation.