Tag Archives: Physical exercise

Flaw in the yoga -cognitive impairment study

29 Jul

On Wednesday, I blogged about a new study of the effects of yoga on cognitive impairment. Thinking it over, I realized that some of the study’s results rest on a serious methodological flaw.

The study compares measures before the intervention to measures after the intervention within in each group. For example, it looks at the Geriatric Depression Scale scores for the yoga group before and after the intervention and says that there is a statistically significant difference. But this is not the correct analysis, we want to compare the changes between the yoga group and the control group. An appropriate procedure would have been a gain score analysis. The authors could have subtracted the after treatment scores from the before treatment scores and then compared those two values using an appropriate statistical test.

In the other words, the study had the possibility of comparing the control and the experimental group but failed to so. All it really says it that the scores improved in the treatment group. That is an interesting finding, but it should be considered only exploratory and suggestive. I have no objection to publishing exploratory findings, I have done so myself. But the authors had the opportunity to make a better test and they failed to do so.

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Physical Exercise Improves Vocabulary Learning

9 Sep

A PLOS paper titled: “Physical Exercise during Encoding Improves Vocabulary Learning in Young Female Adults: A Neuroendocrinological Study.” Here is the abstract:

“Acute physical activity has been repeatedly shown to improve various cognitive functions. However, there have been no investigations comparing the effects of exercise during verbal encoding versus exercise prior to encoding on long-term memory performance. In this current psychoneuroendocrinological study we aim to test whether light to moderate ergometric bicycling during vocabulary encoding enhances subsequent recall compared to encoding during physical rest and encoding after being physically active. Furthermore, we examined the kinetics of brain-derived neurotrophic factor (BDNF) in serum which has been previously shown to correlate with learning performance. We also controlled for the BDNF val66met polymorphism. We found better vocabulary test performance for subjects that were physically active during the encoding phase compared to sedentary subjects. Post-hoc tests revealed that this effect was particularly present in initially low performers. BDNF in serum and BDNF genotype failed to account for the current result. Our data indicates that light to moderate simultaneous physical activity during encoding, but not prior to encoding, is beneficial for subsequent recall of new items.”

 

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Is your workout more important than your job?

8 May

Joshua Stiemle thinks so:

 “I schedule my workouts during the workday and prioritize exercise over all my work activities. ”

“If exercise stops, then my health goes downhill. With the loss of physical health my productivity at work goes down. I become depressed. I lose motivation to do the things that makes my business successful. I’ve learned firsthand that excellence in one area of my life promotes excellence in all other areas of my life. Exercise is the easiest area of my life to control. It’s easy to measure. Either I get it in, or I don’t. When I do, it lifts up all other areas of my life, including my business.”

 

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“High impact running improves learning.”

4 Apr

A paper from 2006. Here is the abstract:

“Regular physical exercise improves cognitive functions and lowers the risk for age-related cognitive decline. Since little is known about the nature and the timing of the underlying mechanisms, we probed whether exercise also has immediate beneficial effects on cognition. Learning performance was assessed directly after high impact anaerobic sprints, low impact aerobic running, or a period of rest in 27 healthy subjects in a randomized cross-over design. Dependent variables comprised learning speed as well as immediate (1 week) and long-term (>8 months) overall success in acquiring a novel vocabulary. Peripheral levels of brain-derived neurotrophic factor (BDNF) and catecholamines (dopamine, epinephrine, norepinephrine) were assessed prior to and after the interventions as well as after learning. We found that vocabulary learning was 20 percent faster after intense physical exercise as compared to the other two conditions. This condition also elicited the strongest increases in BDNF and catecholamine levels. More sustained BDNF levels during learning after intense exercise were related to better short-term learning success, whereas absolute dopamine and epinephrine levels were related to better intermediate (dopamine) and long-term (epinephrine) retentions of the novel vocabulary. Thus, BDNF and two of the catecholamines seem to be mediators by which physical exercise improves learning.”

 

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Stroop test to improve running?

28 Mar

University of Houston cross-country coach, Steve Magness, uses the Stroop test to train his athletes for mental focus:

“While Magness—who once ticked off a 4:01 mile himself—coaches the fundamentals as good as anyone, he goes beyond traditional physiological training strategies to squeeze every ounce of performance out of his athletes. His secret: focusing on the mind.”

To experience the Stroop Test try reading the words below out loud:

download

Kawashima uses Stroop performance as an outcome measure in his “Train Your Brain” program.

Magness also makes an interesting observation about meditation:

‘“I really liked the idea of mindfulness-based meditation because I thought it could quickly transition an athlete from the stress of a workout to the recovery phase,” Magness says. “But I soon learned meditation takes a lot of practice, and for beginners, meditation can be stressful in and of itself.”

Magness started experimenting with other ways to facilitate recovery, like calming and relaxing music, but discovered what was most helpful—based on measuring heart rate variability, a common indicator of recovery—was creating a laid back social environment immediately after hard workouts. “Going from a high-stress workout to a desensitized period of just joking around together decreases tension way faster than anything else we’ve tried,” says Magness. “So now, it has kind of become part of our program to force fun social interactions after intense workouts.”’

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How good is your exercise tracker?

13 Feb

The Journal of the American Medical Association has published a rigorous comparison of several popular exercise trackers:

fitness_wearables_vs_smartphone_1

With the exception of the Nike Fuelband most of the trackers did fairly good job of measuring steps. However, the Digi-walker SW-200 , a less expensive dedicated pedometer, out performed many of the smartphone apps.

I have been very happy with my Omron pedometer. For me, the only drawback is the inability to sync it to statistical software.

But overall, the message seems to be that most exercise trackers will give you a reasonable approximation of how much you exercise.

For more discussion of these findings see this interesting post by Ernesto Ramirez at The Quantified Self.

 

 

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Weight lifting improves memory

4 Oct

 

the study was published in Acta Psychologica, the paper can be found here. Here are the study highlights:

“• We investigate the effects of resistance exercise on emotional episodic memory.
• We measure physiological state with heart rate, blood pressure, and alpha amylase.
• We use a knee extension/flexion task for resistance exercise.
• We find that resistance exercise during consolidation can benefit memory.
•We find effects of valence based on the physiological response to the exercise.”

From the discussion section:

“There are many potential therapeutic benefits of resistance exercise, both physical and cognitive, like the episodic memory benefit we have shown here. Unlike moderate long-term aerobic exercise, single bouts of resistance exercise are easy for a wide range of people with variable levels of physical ability to perform. We are not suggesting that single bouts of resistance exercise can replace the obvious health and cognitive benefits incurred from long-term aerobic interventions. Indeed, future research should examine the potential benefits of long-term resistance exercise interventions on the kinds of memory tasks used in the present study in order to determine the duration of these benefits and whether they may even delay cognitive decline in older adults and neurological patients.”

 

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Telomere trifecta

3 Oct

This is my third blog post in three days on telomeres. I think the subject is important and may yield new insights into human health.

Today I am going to share another video from Dr. Greger about the role of diet in telomere length:

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Running improves learning.

13 Sep

I recently came across a 2007 paper titled “High impact running improves learning.” Here is the abstract:

“Regular physical exercise improves cognitive functions and lowers the risk for age-related cognitive decline. Since little is known about the nature and the timing of the underlying mechanisms, we probed whether exercise also has immediate beneficial effects on cognition. Learning performance was assessed directly after high impact anaerobic sprints, low impact aerobic running, or a period of rest in 27 healthy subjects in a randomized cross-over design. Dependent variables comprised learning speed as well as immediate (1 week) and long-term (>8 months) overall success in acquiring a novel vocabulary. Peripheral levels of brain-derived neurotrophic factor (BDNF) and catecholamines (dopamine, epinephrine, norepinephrine) were assessed prior to and after the interventions as well as after learning. We found that vocabulary learning was 20 percent faster after intense physical exercise as compared to the other two conditions. This condition also elicited the strongest increases in BDNF and catecholamine levels. More sustained BDNF levels during learning after intense exercise were related to better short-term learning success, whereas absolute dopamine and epinephrine levels were related to better intermediate (dopamine) and long-term (epinephrine) retentions of the novel vocabulary. Thus, BDNF and two of the catecholamines seem to be mediators by which physical exercise improves learning.”

Here is a video showing language learning (Korean in this case) while walking:

 

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Why you need to take short walking breaks

12 Sep

When I work at my desk I set a timer for 25 minutes. Each it sounds, I stand up or walk for 5 minutes. I started doing this as part of my very imperfect efforts to implement the pomodoro technique. While I have not been completely satisfied with the effects on my productivity, it has been hard to organize my work into meaningful 25 minute units, I have noticed a reduction in back pain.

Here is a press release on research at Indiana University on the health effects of short walking breaks:

 

‘The researchers were able to demonstrate that during a three-hour period, the flow-mediated dilation, or the expansion of the arteries as a result of increased blood flow, of the main artery in the legs was impaired by as much as 50 percent after just one hour. The study participants who walked for five minutes for each hour of sitting saw their arterial function stay the same — it did not drop throughout the three-hour period. Thosar says it is likely that the increase in muscle activity and blood flow accounts for this.

“American adults sit for approximately eight hours a day,” he said. “The impairment in endothelial function is significant after just one hour of sitting. It is interesting to see that light physical activity can help in preventing this impairment.”‘

(Hat tip to BoingBoing)

Here the Awkward Web Guy explains the pomodoro technique, He has some interesting suggestions that I may try:

 

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