Weight training may stave off dementia in seniors: study
Exercise programs, especially those involving resistance (weight) training, help stave off progression to dementia in older people already showing signs of cognitive impairment, local researchers have shown in a study published in the Archives of Internal Medicine.
The randomized, controlled study compared the effects of three different types of exercise, done twice weekly over six months, in 86 women between the age of 70 and 80. The study compared walking (aerobic exercise), with balance, tone and stretch classes and resistance training to build muscle strength. The latter method produced the best results for memory and other cognition measurements.
All forms of exercise generally produced positive changes in the study, the first of its kind looking at types exercise and its effect on attention, memory, problem solving and decision making. But resistance training fared best, possibly because it gets progressively harder as people increase weight resistance, so it benefits “multiple domains [in the brain] in those at risk for dementia,” the study posits.
“We can’t say resistance training exercise eradicates Alzheimer’s disease but it does show promise in delaying the onset. It improves brain function in the processes that are associated with aging and the early stages of Alzheimer’s disease,” said lead author Teresa Liu-Ambrose, a researcher with the Centre for Hip Health and Mobility at Vancouver General Hospital, Vancouver Coastal Health and the University of B.C. Brain Research Centre.
Most of the funding for the $100,000 study came from the Pacific Alzheimers Research Foundation.
Liu-Ambrose, who is also an assistant professor of physical therapy at UBC, said she hopes the research will convince community centres, gym operators and others that it is both safe and beneficial for seniors to weight train and to offer more programs to older adults. It is often difficult for seniors to find programs, she said, adding she has heard seniors complain they are often rejected by personal trainers who are reluctant to take on clients over age 75.
“That’s a shame, really, because as we’ve shown through our research, seniors are very capable and dedicated.”
Liu-Ambrose said since more than half of those with mild cognitive impairment are eventually diagnosed with Alzheimer’s, it is critically important to find interventions that may “alter the trajectory of cognitive decline in seniors.” Moreover, seniors with cognitive impairment fall twice as much as those without mental impairments, she said.
In 2010, another study led by Liu-Ambrose showed a once-weekly, hour-long program of resistance training resulted in fewer doctors visits, less medication and a lower overall health care costs for women aged 65 to 75. In that study, strength training outperformed twice-weekly balance and toning exercises. Liu-Ambrose said it’s possible that balance and toning exercises don’t produce as much effect on the brain as the other types of exercise because they are more static and less challenging.
In the latest study, participants were already showing signs of mild cognitive impairment when they enrolled in the summer of 2009, but they were considered otherwise healthy and lived independently in the community. They either drove or took public transit to get to classes led by certified fitness instructors on the Vancouver General Hospital campus.
Those assigned to resistance training used free weights and a universal-type gym, while the aerobic group walked, sometimes with walking poles. The balance and tone exercise group did range of motion exercises, stretching, core strength, balance and relaxation exercises.
Aside from a few participants who tripped on curbs in the walking group or missed sessions due to flu or muscle aches, Liu-Ambrose said there were no serious problems and no dropouts because of injuries.
In the next phase of the study, researchers will analyze MRI scans of study participants who performed cognitive tasks while in the machine undergoing a test called functional MRI. Previous research has shown brain volume changes with exercise in the elderly, possibly due to clearance of inflammation. Another study, for which participants are now being recruited, will look at the effects of exercise in those with vascular dementia or a history of small strokes.
“I am already convinced of the positive effects of exercise on aging but we need to refine the prescription for exercise through evidence. We need to be able to say who will benefit from what specific forms of exercise,” Liu-Ambrose said, adding the current study involved only female subjects because of evidence in previous research showing women derive more brain benefits from exercise. It is unclear why that is, but it could be because exercise stimulates production of circulating estrogen, encourages socialization, or some combination of both.