Walk a few miles a week to maintain your brain volume

Published online prior to publication by Pittsburgh investigator Erikson in the journal Neurology yesterday is a study reporting the link between physical activity and brain volume and function in the elderly. The 299 participants examined, averaging age 78 at the time the study began, were part of a study of cardiovascular health. The investigators looked at the relationship between physical activity, brain volume, and cognitive function. They split participants into 4 groups according to how much they walked during an average week (the range was 0-300 blocks per week). Brain scans were done 9 years later and cognitive function tests were done 13 years later. Yes, folks, you read that right, 9 and 13 years. These authors certainly cannot be accused of short follow up periods. Those who had been doing more walking maintained greater brain volume, associated with better cognitive function than those who did not walk a lot. Increasing amounts of walking up until 72 blocks per week were associated with improvements in brain volume and cognitive function. Greater amounts of walking than 72 blocks did not result in further increases in brain volume. So, keep trotting, trekkers!

Ineffective: glucosamine and chondroitin for arthritis

A new meta-analysis (a synthesis of many randomized cinical trials) by Juni and colleagues published in the British Medical Journal this week has found that glucosamine and chondroitin supplements, popularly prescribed and taken for arthritis,are not significantly effective in reducing the joint space narrowing that comes from arthritis nor the pain intensity of arthritis.

10 years ago I was asked to answer a question on a Johns Hopkins "Intellihealth" question and answer site about whether glucosamine and chondroitin were effective for arthritis. I said that taking these things for arthritis would be expected to be about as effective as eating kidney would be for kidney disease, or brains for neurodegenerative disorders. I was very surprised, then, when some trials showed an effect of these compounds and I had to retract my answer. So I guess I can feel a little less concerned that I misled anyone in the past, seeing from this meta-analysis that the industry-independent studies show very little or no effect and even the ones funded by the pharmaceutical and supplement industries show very tiny effects of no clinical significance.

While there doesn't seem to be anything toxic about taking these compounds, and they may have very small effects, they are expensive. I agree with the authors that insurers probably should not pay for them given the hundreds of more effective preventive interventions in medicine which right now are not being paid for by health insurance which should take higher priority, which for arthritis would include exercise or yoga classes.

Only one in twenty working out

Wow, this statistic was much worse than I thought...

Get Off Your Can!

A study in online July 22 in the American Journal of Epidemiology by Alpa Patel and colleagues concludes that sitting shortens our lives, even after considering impact of being overweight and how much we exercise. The study collected questionnaire data for 14 years (1993-2006) from 123,216 healthy people (53,440 men and 69,776 women) in the American' Cancer Society's Cancer Prevention II study.

Even after considering body mass index (BMI) and smoking, women who spent six hours a day sitting had a 37 percent higher risk of dying than those who sat for less than three hours a day. Men had a 17% higher risk. Exercise lowered the risk of sitting, but more sitting meant a higher risk of death even among those who exercised. And for those who didn't exercise, sitting a lot was even worse: women who sat a lot had a 94% higher risk of dying than women who didn't, and for men, sitting conferred a 49% higher risk of death.

So start moving; you can still read this blog on your mobile while moving! Disclaimer: Don't read while walking out in the street! More dangerous to your health than sitting....

New Formula for Females for Maximal Workout Heart Rate

A new formula for women to calculate their maximal heart rates for workouts has been put forth by researchers at Northwestern in a study published in Circulation this week. This new formula was based on a study of 5500 healthy women who took treadmill tests in 1992 and who were followed for mortality. This formula is the first which used women to look at how heart rates with exercise were related to mortality rates, and is therefore likely to be much more accurate than the usual formula for peak heart rate which exercise professionals had used (220 minus age). The new formula, 206 - 88% of age, is a little harder to calculate. For example, for a 50 year old woman, the new formula's peak heart rate is 206 - (.88x50) = 162. If one uses 65% - 85% of the maximal heart rate of 162 for the target heart rate range for workouts, a 50 year old woman should be able to get to 138 as she becomes more fit but would not reduce, and might increase, her cardiovascular mortality by pushing herself further than that.

This study provides valuable guidance for women as they endeavor to become fit and will be a relief to women who have been trying to push themselves to the old formula's upper limit target rate.

feedback about our health: the ODL

Today I received a newsletter from AHIP, the friendly association of health plans. I learned again about the phrase "observations of daily living", or ODL's. This phrase is bandied about in some projects funded by the Robert Wood Johnson Foundation, studying whether automatically recorded data about our daily lives can help us manage our health. A variety of devices out there are designed to provide real time feedback about our diets, our exercise habits, sleep, sex, smoking, etc.

(I imagine that next - you heard it here - the neurotic and narcissists among us will be replaying our interpersonal interactions in real time for our mental health professionals...my prize is going to go to the person who gets our dreams and waking fantasies to be automatically recorded...)

Fantasies and cynicism aside, these data are extremely helpful to all of us in managing our habits. They can be useful for our physicians in determining what we need help with. However, of course they will also be used to inform our insurers for about our risk status. Be cautious, then, whose tool you use and where the data are going. Make sure the information from these devices goes to a record under your control, not your insurer's. If you are uploading data to your provider organization, is your provider organization authorized to release that data to insurers? These observations bring medical privacy concerns to a new level.

So check out the Zeo a device marketed to consumers that analyzes your sleep. Or Body Media Fit. Several others are listed at Wired.com

The Workout Desk

Exertophobic (is that a word?) desk potatoes - hold the sour cream and take note! Now you can work out while you're sitting at your desk, and not virtually, either.

http://www.ivanhoe.com/science/story/2010/03/689a.html