Go lift some weights and call me in the morning

In my last post I told you that I would reveal the one thing you can do to have a significant, positive and lasting effect on your brain health as you get older. See if you can spot it in the following list:

a) Learn to dance Gangnam style
b) Join a choir
c) Catch a wave
d) Pump some iron

Ok, that was a trick question. All of these answers are somewhat correct, but I was looking for the "most" correct answer (flashbacks to undergrad, anyone?): Pump some iron.

I realize I sound like a broken record - I've already written about how aerobic exercise can promote healthy aging here and here, and I've even already written about resistance training, or lifting weights, here.

So why am I at it again? Because it's important!
I'm fresh out of the 2012 Aging and Society Conference, where researchers came together to discuss what works and what doesn't when it comes to healthy aging. It turns out everyone pretty much agrees that exercise is hands down the most effective intervention to keep your brain cells happy into old(er) age. All sorts of different types of exercise, ranging from simply walking to attending resistance training classes, are associated with different types of improvements in cognition, memory, and even brain size. 

Of course, there are different levels of effort involved with different types of exercise, or even when talking about a single form of exercise. When my friend Jess asks me to go for a walk, she means a power walk: it usually involves going up hills, sweating like a pig (even though pigs, ironically, don't sweat much), and barely having enough breath for girl talk (though somehow we always seem to find it). When my friend Al and I go for a walk, what he means is a "mosey": we stop to look at the view, pet the dog, chit chat with strangers, and have more than enough breath for lengthy discussions about life, work, and the possibility of alien lifeforms. When it comes to brain health, whether you're walking or pumping iron, a little sweating and effort can go a long way. For example, resistance training has been proven to be most effective when the load, or how much weight you are working with, increases over time. So kick the intensity up a notch: there will still be plenty of time for chit chat around a post-exercise, antioxidant-rich mug of matcha (my new obsession - stay tuned).

Now that the obvious has been (re)stated, I want to take this opportunity to discuss the idea that perhaps lifestyle interventions such as exercise could be prescribed by your doctor. We know that exercise can improve cognition in aging but also conditions like depression. Should physicians prescribe lifestyle changes? Or are diet, exercise, and other lifestyle activities choices we should make ourselves? How would you feel if your doctor prescribed you exercise instead of pills? Would you be more motivated to exercise if the prescription came from your doctor instead of from your friendly Internet science blogger? Your thoughts in the comments!

Run Run Rudolf

I consider myself a fairly healthy person and I rarely get sick. However, there is one activity that never fails to put me under the weather: flying. No matter how hard I try, no matter how much I wash my hands and try not to touch my face, any flight inevitably leads to some kind of illness. It usually ends up being a common cold, but I remember a nasty Christmas holiday spent in bed with a stomach flu. In any case, my recent flight home from San Diego was no exception, and here I am, still battling a stupid cold. So naturally, I looked for an article on how to prevent colds.

In a recent study, researchers followed over a thousand adults (18-85 years old) for 12 weeks during the fall and winter seasons. Over this time, the participants had to report two measures: any symptoms of upper respiratory tract infection (such as a cold), and how much they exercised.

While running in the cold winter air might sound like a counterproductive measure to prevent colds, the researchers found that participants who reported being physically active (aerobic exercise) five days a week or more experienced significantly less cold and flu symptoms (a 43% reduction in number of days with an illness). This relationship held true event when several factors were controlled for, such as dietary habits (eating lots of fruits and veggies) and stress levels.

Why might exercise prevent colds? While we don't have a clear cut answer to this question, animal studies suggest a few leads. When you exercise, you increase the circulation of cells that are important for immunity and that are involved in fighting off the bad guys. More specifically, exercise has been shown to boost macrophages (cells that eat up invaders) in your lungs. In addition, exercise can lower the levels of immunity-compromising stress hormones.

Is there anything exercise can't do? Now I need researchers to study how one can be motivated to exercise when they are sitting in a comfy chair by the fire with a mug of chai tea and a pile of work to do and it's below zero outside. Tell me something I don't know, right?

Reference: Upper respiratory tract infection is reduced in physically fit and active adults. (2010) Nieman DC et al. [Epud ahead of print].

The little-known benefits of pumping iron

At the risk of sounding like a broken record, exercise is good for you and your brain. That being said, most studies looking at exercise and cognitive function evaluate aerobic exercise (the kind that gets your heartbeat going). The other kind of exercise, resistance training (strength training with weights), has not been of much interest, perhaps due to the old stereotype that has been plaguing bodybuilders forever: big biceps, small IQ (although big biceps never stopped anyone from becoming governor of California). Switch the young lads for older women, though, and a recent study from a team of researchers at the University of British Columbia (represent!) suggests that gaining muscle can translate into a better brain.

The study looked at 135 women between the ages of 65 and 75 over the course of a year. The women were assigned one of three groups: group one took a one-hour resistance training class once a week, group two took a one-hour resistance training class twice a week, and group three, the control group, took a one-hour balance and stretching class twice a week. The women were all evaluated for a range of cognitive functions at the start of the study, at the six-month point, and at the end of the study (at the 12-month point).

The bad news is that strength training for six months, whether once or twice a week, didn’t lead to any changes. The good news is that if you stick to it for a year, you only need to train once a week to see an effect. After 12 months, the researchers found that all the women who underwent strength training showed a significant improvement in attention. The researchers evaluated attention using the well-established Stroop test (see image below), where the names of colors are written in an ink of a different color (for example, the word blue is written in red ink). To assess attention, the participants were asked to name the color of the ink (and not the word) as fast as they could (try it!). The once-a-week and the twice-a-week resistance training groups significantly improved on this task, while the performance of the balance and stretching group slightly deteriorated.

This improvement in cognitive function didn’t come without a price. The women in the once-a-week resistance training group complained of joint and muscle pains more than the women in the two other groups. It seems that the sweet spot for both an improvement in cognition and a lower risk of pain is to train twice a week (at least). This makes sense to me: the more frequently I exercise, the more my body gets used to the motions. It is also worth noting that the researchers tested other cognitive tasks such as memory and these didn’t show any change with resistance training.

Overall, though, I think this study is great news. I know that many older adults shy away from rigorous aerobic exercise (even young adults… *cough cough*), so this could be an easier alternative to help with brain health. And even if the “brain benefits” of resistance training could be a little more impressive (like by curing Alzheimer’s disease, while we’re at it), on the plus side, strength training also improves gait speed (your natural walking speed), and an improved gait speed is associated with a significant reduction in mortality. So if you don’t exercise for your brain, do it for your lifespan.
Reference: Resistance training and executive function: A 12-month randomized control trial. (2010) Liu-Ambrose T. et al. Arch Intern Med 170(2):170-8.

Yet another reason to exercise

Last weekend I went for a bike ride and when I reached the bottom of the big hill leading to UBC, I noticed quite a bit of activity going on. I didn't pay too much attention at first, but once I was booting up the hill, I was passed by several senior citizens on top-notch bicycles and I started getting curious. I asked a person who seemed to volunteer for the event what was going on. As it turns out, I was cycling right in the middle of the BC Seniors Games. Now for those of you who might not know me, my thesis research has to do with aging and the brain and nothing warms my heart like witnessing older adults and seniors exercising. I had just hit the jackpot!

The reason I'm so enthralled to see seniors exercise is because it is the single best thing they can do to preserve their brains. Today's paper highlights recent research done in California that shows just that.

First, a bit of background. You have a gene called APOE (mice also have it). It comes in 3 flavors, and each person only has one of the three: APOE2 (not important for today’s article), APOE3 and APOE4. If you got lucky and scored the APOE3 kind, all is well. If you happen to be in the 20-25% of the population who has the APOE4 kind, you may be in trouble: APOE4 is a known risk factor for Alzheimer's disease. Does it mean you'll for sure get Alzheimer’s disease? No, but you are 10 to 30 times more at risk of developing Alzheimer's disease if you carry the APOE4 gene.

In this paper, researchers compared old APOE3 (normal) and APOE4 (at risk for dementia) mice. In general, aged APOE4 mice experience cognitive decline faster and earlier than APOE3 mice. The researchers were interested in studying whether exercise (running on a mouse wheel!) had any effect on this cognitive decline.

The researchers used cognitive tasks that rely on a part of the brain that's important for memory, the hippocampus. One of the tasks, called place recognition, involves putting a mouse in an arena with two objects. The mouse is then removed from the arena, one object is moved, and the mouse is put back in the arena. Presumably, a normal mouse will then spend more time exploring the object in the new location. For this task, the aged APOE4 mice were initially impaired compared with the APOE3 mice. This means that during the second trial of the task, they tended to explore both objects for similar amounts of time, instead of spending more time on the object at the new location. This result suggests that the APOE4 were unable to remember the initial object locations well. The good news? Mice who exercised did significantly better at this task. Interestingly, this was valid for both APOE3 and APOE4 mice. Even more interestingly, exercise improved the scores of both types of mice for all the tasks that tested the hippocampus.

What's going on in the brains of these exercising mice? It is thought that exercise increases the levels of a protein called BDNF (for Brain-Derived Neurotrophic Factor). BDNF regulates many important functions in the brain, including the making of new neurons and the making of new connections between neurons, and these effects are thought to be important for memory.

Regular readers of Scientific Chick know not to get too excited when I report about animal studies. Well, I'm happy to add that the results that were observed in those mice were also observed in humans. In fact, there are countless human studies out there that confirm that physical activity is a powerful way to improve and maintain your cognitive abilities.

When I try to urge certain people to exercise (you know who you are), I almost always hear the same excuse: “Well, my uncle so-and-so never got off his couch and he lived to be 100!” In some cases, heredity can be on your side, that's true. But genetics can be quite the lottery, and it's important to keep in mind that several forms of cognitive decline, including the most common form of Alzheimer's (called “sporadic” in scientific lingo) are not hereditary.

So to all my older readers out there, I'll see you on the road at next year's BC Seniors Games. And if you're not ready for cycling, there's always the cribbage category.

Winners from this year's BC Seniors Games, cycling event. This could be you!

Reference: Exercise improves cognition and hippocampal plasticity in APOE epsilon4 mice. (2009) Nichol K, Deeny SP, Seif J, Camaclang K, Cotman CW. Alzheimers Dement. 5(4):287-94.