Miami Brain Fitness » exercise

Exercise, Mitochondrial DNA, and Brain Fitness

rlo — Sat, 12 Mar 2011 01:54:32 +0000

One very influential theory of why our physical and mental functions decline with age holds that changes in our DNA accumulate over time so that out cells don’t work any more. Perhaps the most important part of our DNA exists in every cell in a special part called the mitochondia. Mitochondria are especially important because they are the part of the cell that helps it generate energy. DNA contains the programs that generate energy, but over time errors accumulate in the programs until eventually they don’t work very well any more. Errors in the programs that run our cells happen all the time — but when we’re younger the cells can fix themselves. As we get older, the cells don’t fix themselves as well. The result: our bodies don’t work as well as they used to. Over time, things start breaking and can’t be fixed. Eventually . . .

A recent study reported in the Proceedings of the National Academy of Science reports on a way to reduce the errors, at least in mice who are prone to an increased number of DNA errors. These mice have an increased number of errors in their DNA, and even early in life start to show signs of aging that are eerily similar to those seen in humans: hair loss, graying, low of body weight, and problems in mobility. Researchers at McMaster University in Ontario, Canada, compared mice with the increased number of errors to regular mice, and looked at what happened if some of the error-prone mice spent time exercising.

The group of the mice who had DNA errors exercised for 45 minutes on three days a week for 5 months. The researchers then compared the three groups: (1) DNA error-prone who didn’t exercise, (2) DNA error-prone who exercised, and (3) regualr mice who had normal DNA. Result: The error-prone mice who exercised looked the same as the regular mice. They weren’t just stronger, or in better shape, or able to run longer. They “lacked visible features of the accelerated aging phenotype (alopecia and graying hair) and were visually indistinguishable from age-matched … littermates” (page 4135).

Does this mean that if you start exercising regularly you can reverse aging? Probably not. But good research continues to accumulate that shows that exercise can improve cognition and keep the effects of aging to a minimum.

You can find an abstract for the article here. To read the full article, you will need a subscription to the journal.

Walking, BDNF, Hippocampal Size, and Brain Fitness

rlo — Wed, 09 Feb 2011 12:53:58 +0000

Maybe I have an obsession. Maybe I’m addicted to exercise. Maybe. But here it is, once again: Yet another study has shown that aerobic exercise is good for your brain. Not only does aerobic exercise improve cognition (at least 20 or more studies have shown that), but it can help to prevent age-related declines in the size of the hippocampus. The hippocampus is a critically important structure in the brain that is a key part of a circuit that creates new memories.It tends to get smaller with increasing age, but exercise can actually increase its size. The increase in size may be related to increased levels of brain-derived neurotrophic growth factor (BDNF), a substance in the body that promotes the growth of new brain cells.

In an article published online on January 31st in the Proceedings of the National Academy of Sciences, researchers show again that regular walking can make a difference in cognition. This study is new because the researchers also looked at the volume of the hippocampus with imaging techniques and looked at BDNF levels.

Exercise and BDNF levels may also be related to the way that antidepressants work to reduce depression, and we know that for many individuals exercise improves mood. While we think of the hippocampus most often because of its role in memory, it also has important effects in regulating emotion.

You can find the abstract here. The full article is available to subscribers only.

Cognitive Training, Gait Speed, and Brain Fitness

rlo — Mon, 13 Dec 2010 02:54:21 +0000

An article in this weeks’ Journal of Gerontology, provides some interesting information on how cognitive training can actually affect someone’s physical status. The article, titled “Effect of Cognitive Remediation on Gait in Sedentary Seniors,” reports on a small group of elders who completed 8 weeks of computer-based cognitive training. The authors found that the elders who completed cognitive training actually showed an increase in walking speed (even though that wasn’t part of the training).

This is significant for several reasons. First, it suggests that a mental activity can have positive effects on someone’s physical status. Said this way, this isn’t all that surprising — we’ve known for many years that relaxation can help to control blood pressure, and that stress management training can help to reduce the risks of heart attacks. The leap to something as basic as walking speed, however, is new.

Second, the study suggests (at least to me) that the link between mental and physical decline may work both ways. We’ve known for some time that exercise, for example, can have positive effects on cognition. This study suggests that the reverse may be true: that cognition can have a positive effect on physical status.

One more reason for all of us to continue to be both mentally and physically active.

Reference:

Verghese J, et al.(2010). Effect of cognitive remediation on gait in sedentary seniors. Journal of Gerontology: Medical Sciences, 65A, 1338-1343.

Alzheimer’s Op-Ed: Give up on Brain Health?

rlo — Fri, 29 Oct 2010 12:42:25 +0000

An important op-ed piece appeared in yesterday’s New York Times authored by Sandra Day O’Connor (former Justice of the US Supreme Court), Nobel prize winner Robert Pruisner, and Ken Dychtwald, a well-known gerontologist.

They argue that prevention of Alzheimer’s disease hasn’t worked because, as they point out, Ronald Regan got Alzheimer’s even though he was both mentally and physically active. They also argue what we really need is a massive increase in research funding to find drug treatments for Alzheimer’s disease. Click here to see the opinion piece.

Is it possible to agree with someone’s conclusion but think that their reasoning is wrong? I think the answer for me has to be yes.

Their argument reflects a basic misconception about prevention. It’s as though we were saying because Jim Fixx (a famous runner) died of a heart attack we should give up on exercise and only focus on drug and surgical treatments for heart disease. It as thought we are saying, Let’s give up being healthy, because even people who exercise and eat right still get heart disease.

O’Connor and her colleagues argue that a major increase in funding for Alzheimer disease drug development might lead more rapidly to effective treatments, and cite the effort made in the 1980s to develop treatment for HIV infection. A similar effort, they argue, would lead to similar progress in Alzheimer’s.

We don’t know that, but there’s only one way to find out. Even though there have been important advances in understanding the basic pathology of Alzheimer’s, it’s still not clear how well treatments based on those advances will work. Recent drug trials have not panned out. A major advance could happen tomorrow, or not for many years.

An alternative model for understanding potential advances in treating Alzheimer’s might be efforts to treat cancer. While major advances in treatment have occurred since the time of the Nixon administration, reductions in cancer rates for things such as lung cancer are also heavily influenced by public health efforts to reduce smoking.

Maybe what we really need is a targeted effort to evaluate both preventive as well as drug treatment strategies in Alzheimer’s. The op-ed piece neglects promising developments such as Carl Cotman’s work on reducing amyloid load in animals that I wrote about several weeks ago. He showed that diet and exercise actually reduced amyloid (a substance believed to be central in Alzheimer’s disease) in aging dogs. That work can lead to preventive efforts but may also lead to drug therapies for cognitive decline and perhaps Alzheimer’s. (See my earlier post here.)

So give up on brain health? I think that’s a really bad idea. We know that people who are healthy as well as physically, socially, and mentally active are less likely to have cognitive decline. Will brain health prevent all Alzheimer’s? Probably not. But should we give up and throw all of our efforts into drug development? Until we have better treatments for cognitive decline, a brain healthy lifestyle is probably the best strategy for staying mentally sharp.

Physical Activity and Cognitive Impairment

rlo — Wed, 04 Aug 2010 11:24:00 +0000

A new study shows that physical activity may reduce the risk of developing cognitive impairment. The INVADE study, completed almost 4,000 people older than 55 years, showed that people who engaged in some form of physical activity three times a week or more were less likely to develop memory problems over two years.

This study showed a relation between “strenuous” physical activity as reported by participants and cognition two years later. Strenuous activities walking, bicycling, swimming, gardening, “or other exercise,” so the types of physical activity were diverse. The inclusion of walking and gardening in the definition of physical activity suggests that even moderate activity may be useful in helping older adults avoid cognitive decline. Persons who said they did some form of activity three times a week were classified as “moderately active” while those who were active more frequently were classified in a “high activity” group.

The bottom line: Another study shows that even moderate activity may help prevent cognitive decline as people age.

Reference:

Etgen T et al. (2010). Physical activity and incident cognitive impairment in elderly persons: The INVADE study. Archives of Internal Medicine, 170, 186-193. Free full text is available at the journal website.