Monday, January 08, 2007

An Excursion Into Exercise

I justify this posting on the grounds that exercise is almost certainly a very important factor in aging. What's really fascinating is that the research in this area seems to be absolutely polarized; those who run rats to exhaustion on treadmills generally conclude that long term exercise increases the production of reactive oxygen species (ROS, or free radicals), with the more-or-less implicit conclusion that exercise increases the rate of ageing. The more benign (or possibly just more patient) researchers who have taken elderly Homo sapiens through an exercise regime universally conclude that it improves quality of life, and there seems to be some evidence that it also contributes to increased longevity [1]. Maybe the rats should be allowed to choose not to run to exhaustion?


I'm an expert on getting into a running program. I'm almost as expert at that as I am at giving up alcohol. And since I'm currently back in Brisbane, where the weather is warm and the work pressures are purely internal, I've been running pretty regularly for the past month or so. There are several really obvious differences between running here and in Newcastle. The weather, of course, is the most obvious. In Brisbane I have to set my alarm for 6:30am to be on the road by 7:30, or it's just too hot to run. In Newcastle it's pitch dark at 7:30, and trying to squeeze in a run and still get to work before lunch time is a major hassle. Not to mention running in the cold. Even your ears hurt!

Then there's the setting. In Newcastle I run around Leazes Park, which is actually really pretty, and extremely Victorian, but too small to hold the interest day after day. Plus it was the pond at Leazes Park into which my motorbike was thrown a few months ago, so it still has painful memories, despite the swans. In Brisbane I have a 5K route that runs, for most of the way, past a creek, through bushland. It's cool and shady and replete with water dragons and sulphur crested cockatoos (no swans, though!) and smells of gum trees and hot grass. I swap smug smiles with the other runners and dog walkers, in tacit acknowledgement of our moral and physical superiority over the local slugabeds.

There is a hitch, however. In the past two months there have been 25 sexual attacks, of varying degrees of severity, upon women exercising on Brisbane's footpaths, including a couple in this area. The local government has offered a $50,000 reward for information leading to a conviction, and is advising women not to exercise alone. This morning I'd only gone a kilometer before encountering a very impressive motorcycle cop on my usual path. It's all a bit depressing.

But what really interested me was the way people responded. I do find myself scanning the path ahead, looking for lurkers, and trying to keep tabs on cyclists who overtake me, in case they turn round and turn evil. It does take my mind off the heat, my lungs and my legs, which I guess is some sort of silver lining. But what I really liked was the fact that it seems to have had no effect on the interactions between the early morning exercise community. We still smile and nod, and mouth "Morning", to each other. It's really encouraging to see that most people aren't letting these bastards get to them.

Lets hope they get these guys soon. A few runs to exhaustion on the treadmill will do them the world of good, and I volunteer to take any physiological measurements that might be useful, with a large syringe, as needed.


[1] Lee, I. M., Hsieh, C. C. & Paffenbarger, R. S. (1995). Excercise intensity and longevity in men. The Harvard alumni health study. Journal of the Americal Medical Association 273(15).

Monday, January 01, 2007

Ageing and Memory

First up, I have to come clean; this post is a shameless plug for a book written by a good friend and colleague of mine, Janet Wiles[1]. But in the course of writing it I had a quick look at the literature, and found lots of other interesting stuff.

My feeling, for which I have no basis except for experience, is that the major health fear of most younger people is cancer; The Big C. And that's probably fair enough; one in four women and one in three men will contract some sort of cancer in the course of their lives. And there are so many different sorts of cancer, with a multiplicity of causes ranging from DNA damage to viruses to diet. Cancer is scary because it's hard to understand and hard to control.

As we age, however, a new spectre raises its head: Alzheimer's Disease. The prospect of slowly losing our memory and cognitive abilities, the very core of what makes a human being, is not one that any of us can face with equanimity. The fact that some decline in memory and cognition appears to be an inevitable part of normal ageing doesn't help, either; most of the older adults I know (myself included) have wondered, at least in passing, if the fact that they can't find the car keys is a Bad Sign.

Janet's book arose from a survey which she and her co-author (and mum!) carried out, about memory function and concerns about memory in older adults. They used the survey to identify the issues which most concerned older people, and then went back to the literature[2] to identify which phenomena are aspects of normal aging, what might indicate some sort of pathology, and what strategies can help with memory problems [3].

I've always assumed that worries about memory are probably unnecessary; surely cancer is much more prevalent than Alzheimer's? [4]. It turns out that this is not, in fact, the case. There have been several large-scale investigations into the incidence of Alzheimer's. Generally, the incidence seems to be aroun 1% of the population at age 65, rising to around 8% once you're over 85. Interestingly, the incidence at age 80 - 84 is around 3%; there's a big jump once the magic 85th birthday hits. Even so, the incidence is pretty low. However, that translates to a lifetime risk of getting Alzheimer's pretty similar to that of getting cancer; around 25%. The good news is that the relationship between brain changes and disease symptoms is not straightforward; most people age 90 have Alzheimer's-like changes in the brain, despite not having dementia. And some factors, like education, appear to be neuroprotective. So, get educated... the book!


[1] Wiles, J. & Wiles, J. (2007). The Memory Book: Everyday Habits for a Healthy Memory. Apple Press. Available from Amazon UK.
[2] Janet is a cognitive scientist, and has in the past spent an unhealthy amount of time with psychologists. Nowadays we've lured her back into the relative sanity of the computer science department.
[3] When the local news in Brisbane did a segment on the book, I got to be interviewed confessing to the world that I can't remember a thing unless I write it down. Thanks, Janet!
[4] And, of course, heart disease or road accidents are far more likely than either.