Strength training for brain function

Strength training increased the brain function of a group of older women according to a new study published this month in the Archives of Internal Medicine. Significant improvements were seen in executive functioning skills, including selective attention and conflict resolution. Strength training may be an effective way to prevent the decline in mental function associated with aging.

The take home messages:

• strength training may reduce the decline of brain function. It does this by actually improving executive functioning skills like selective attention and conflict resolution. Lift weights and you will be better able to multitask, be productive, and enjoy work, play, and life.
• How long: it may take a while (12 months vs. 6 months) to see the effects on cognitive functioning, but the effects are statistically significant
• How often: it does not matter if you strength train once or twice a week–both schedules benefit the brain. The difference in benefits between once or twice a week is small. So get moving! However often you can. No amount is too little!

Why Care?

Cognitive decline among older adults is a pressing health care issue. Many adults dread, fear, or already live with the realities of mild cognitive impairment and dementia. Research into pharmacological interventions (i.e. drugs) continues and we search for “cures”. But the cognitive decline of old age need not be our destiny. The Canadian researchers were motivated to find effective primary prevention strategies for age-associated cognitive decline.

The researchers noted that previous studies indicated that physical activity might limit our spiral down towards forgetfulness and senility. These previous studies did not differentiate between aerobic activity and resistance training. Further investigations into aerobic exercise (running, walking, whatever that gets your heart pumping) have shown a that aerobic training enhances brain and cognitive function. Aerobic exercise was even shown to spur the creation of new brain cells that appear biochemically resistant to stress (and we all know stress is a major component of aging.)

Less research had been done on the effect of strength training. A promising study in 2007 showed that seniors improved memory performance and verbal concept formation after resistance training. ¹ The researchers asked themselves if perhaps strength training improved a wider range of brain functions.

The researchers studied the effect of resistance (strength) training on brain function.

Research Study Breakdown

Who were the subjects?

155 women, aged 65 to 75 years. The women lived independently in Vancouver and were receiving neither estrogen nor testosterone therapy.

The researchers randomly assign each women to one of three groups:

1. 54 for once-weekly resistance training
2. 52 for twice-weekly resistance training
3. 49 for twice-weekly balance and tone training (control group)

What kind of trial was it?

Single-blinded randomized.

The assessors were blinded to which group the women had been assigned.

What was the strength training (the intervention)?

Used a progressive, high intensity protocol.

6-8 repetitions; 2 sets

Resistance (weights) increased as exercises completed with proper form and without discomfort.

Exercises included:

• biceps curls,
• triceps extension,
• seated rowing,
• latissimus dorsi pull-down exercises,
• leg presses,
• hamstring curls, and
• calf raises.
• minisquats,
• mini- lunges, and
• lunge walks.

What was the balance and tone training (the control)?

Included: “stretching exercises, range of-motion exercises, basic core-strength exercises including kegels (ie, exercises to strengthen the pelvic floor muscles), balance exercises, and relaxation techniques.

Key balance exercises included

• tai chi–based forms (i.e., the crane and the tree pose),
• tandem stand, tandem walking, and single leg stance (eyes opened and closed).

Other than body weight, no additional loading (eg, hand weights or resistance bands) was applied to any of the exercises. There is no evidence that these exercises improve cognitive function.”
(from the research paper)

How long was data collected?

Over 52 weeks. (2007-2008)

Data collected once at beginning, midpoint, and end of the trial.

What did the researchers seek to measure?

Executive cognitive function.

Executive functioning is the fancy name for a set of cognitive skills.

Executive functioning is traditionally believed to be located in the frontal lobes, or in the prefrontal cortex. Located behind your forehead, this part of the brain experienced explosive growth in our evolution from apes to humans.

So what are executive functioning skills?

These skills are exemplified by an executive and his secretary. Skills such as planning, decision-making, organizing information, impulse control (initiation and inhibition), working memory, selective attention, and multitasking. Your ability to make phone calls while you research the web, prepare coffee, and feed the dog is an example of multi-tasking. Your ability to figure out what to pay attention to in this media/information saturated world (think: Times Square) is selective attention. Your ability to remember a telephone long enough to dial it is working memory. Your ability to resist the temptation of a second dessert is impulse-control. Your ability to decide which sandwich you’ll have off the new lunch menu is decision-making. Your ability to plan tomorrow’s schedule or to plan for a house purchase are planning.

In sum, executive functioning is ESSENTIAL to your daily life.

A side note on teenagers:

Think of all the things teenagers are famous for: poor decision making (did you really believe it was a good idea to place the cat on skateboard and send it down a hill?) ; risky behavior (inability to decide and appreciate consequences) ; impulsivity (lack of inhibition, not seeing or worried about consequences); less inhibition ; distracted- or spacey-ness.

It is believed that the prefrontal region in teenage or adolescent brain functions less fully relative to adult brains. Instead, the more emotional regions are more active in younger brains than in adults. So the answer to the cat-skating-down-the-hill question is: yes….it seemed like a good idea at the time.

In the research, the components of executive function were measured:

• Primarily focus: selective attention and conflict resolution,
• Secondary focus: set shifting, and working memory

How was brain and cognitive function measured?

• Selective attention and conflict resolution were measured via a Stroop test.

(For a description of the Stroop test and Stroop effect and to try it out).

• Set shifting was measured via the Trail Making Tests part A and B.

(In this test you find and draw a trail connecting letters and numbers, alternating letters and numbers in alphabetical and numeric order. i.e. 1-A-2-B-3-C etc. Again, like the Stroop test, what matters is the difference in difficulties for various orders.)

• Working memory was measured via a verbal digit span forward and backwards.

(In this test you report back the exact sequence of list of numbers. If the tester says 2-6-1-8, you say 2-6-1-8. The list of numbers grow increasingly longer. Then test is repeated with a new set of numbers, except this time you must report back the list backwards. If the tester says 5-7-3-0, you say 0-3-7-5. Again, what matters is the difference in scores between the forward and backwards version of the test.

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What else was measured?

• gait speed,
• quadriceps muscular function, and
• whole-brain volume (via MRI)

in order to understand the wider range of effects resistance training.

What were the study results?

The women who did the strength training experienced a significant improvement in their cognitive functioning scores at the end of the trial on the Stroop test (selective attention and conflict resolution)

To note,

• there was no difference between groups’ Stroop tests at midpoint (6 months), only at the end (12 months)

It’s good to note that improvements may not be seen for some time, so not to be discouraged. On the other hand, we are creatures of instant gratification and instant rewards. Many people will not wait so long. Ask yourself: is 6 more months of exercise worth 20 or 30 years of mental impairment and reduced independence?

• both the once a week and twice a week strength training groups saw significant cognitive improvement (selective attention and conflict resolution)

1xweek = 12.6% improvement
2xweek = 10.9% improvement

So if you can exercise twice a week, great! But if you miss one day, don’t throw the whole plan out–do it once a week. You still get tremendous benefit.

• No statistically significant difference was found between groups on set shifting or working memory at the midpoint or end of the trial.
• Interestingly, improvement in selective attention and conflict resolution (i.e. Stroop test scores) was significantly associated with improvement in gait speed.
• Unexpectedly, the strength training groups who had improved brain function, actually decreased their whole-brain volume. The researchers cite some precedents but generally leave this result as question for further research.

The take home messages:

• strength training may reduce the decline of brain function. It does this by actually improving executive functioning skills like selective attention and conflict resolution. Lift weights and you will be better able to multitask, be productive, and enjoy work, play, and life.
• How long: it may take a while (12 months vs. 6 months) to see the effects on cognitive functioning, but the effects are statistically significant
• How often: it does not matter if you strength train once or twice a week–both schedules benefit the brain. The difference in benefits between once or twice a week is small. So get moving! However often you can. No amount is too little!

References and further reading

• New York Times: Vital Signs Exercise: In Women, Training for a Sharper Mind (01/26/2010)
• Discussion of study motivation and design from the research paper itself: Resistance Training and Executive Functions: A 12-Month Randomized Controlled Trial. Teresa Liu-Ambrose; Lindsay S. Nagamatsu; Peter Graf; B. Lynn Beattie; Maureen C. Ashe; Todd C. Handy. Arch Intern Med. 2010;170(2):170-178.
• Pubmed: Cassilhas RC, Viana VA, Grassmann V, Santos RT, Santos RF, Tufik S, Mello MT. The impact of resistance exercise on the cognitive function of the elderly. Med Sci Sports Exerc. 2007 Aug;39(8):1401-7. PubMed PMID: 17762374. Study CONCLUSIONS: Moderate- and high-intensity resistance exercise programs had equally beneficial effects on cognitive functioning. Footnoted [1]

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This entry was posted on Thursday, January 28th, 2010 at 10:10 am. It is filed under Learn : Understand : Apply, Research, Research Study Breakdown and tagged with Aging, Brain, Cognitive, Executive functioning, Exercise, Exercise benefits, Health care reform, Mental decline, Research, Strength training, Teenage brain. You can follow any responses to this entry through the RSS 2.0 feed.