In the last five posts here I’ve been examining the effects of aging on my training, racing and life in general (vision, recovery, more on recovery and vision, race weight, performance). It appears that I’m starting to realize the consequences of 69 years of living. Due in part to my level of physical activity for most of those nearly seven decades I’ve seen very little reason to be concerned about my decline. It’s been minimal to non-existent. But as I explained in my last post on performance, the changes seem to be accelerating this year as I approach my 70 birthday in a couple of months. Or are they? It’s hard to see the forest for the trees. I’m sure it will be a year or more until I know for sure. But for right now I’m focused on understanding what’s happening and doing my best to control the rate of decline.
So what is it that happens to athletes as we age? There is a ton of research on this topic, some better than others. There are two types of studies you find when searching the scientific literature. The most common are called “cross-sectional” studies. These examine two groups of subjects – one “older” group (the researchers are kind in never referring to us as “old”) and a group of young athletes. They typically assign these groups so that gender, body size, training and other variables are similar. Then they simply measure the physiological differences between the two groups and assume the differences are the result of aging. These studies are relatively easy to do because, for one thing, they don’t take much time. The study can be completed in a few weeks time.
The other type of aging study is “longitudinal.” This is the gold standard. A group of athletes is studied over time, often for several years or even decades, to see what happens to them physiologically speaking. Cross-sectional studies are hugely dependent on how the subjects were selected (was a key element of change unaccounted for when selecting the subjects, such as lifestyle or diet or smoking or type of work or even culture?). Something overlooked could account for much of the change and have little or nothing to with aging. That would render the results useless in trying to understand what happens to athletes as they age.
On the other hand, in longitudinal studies the independent variables are just a part of life and can be assumed to help account, at least in part, for the physiological changes taking place over time. They sometimes become obvious predictors of change, such as reducing training load or stopping training altogether. The data is more reliable since it’s real people living real lives as we follow their progress. The downside of these studies is that the researchers must invest years and years into following the subjects (people move, become difficult to reach and even die) and measuring the changes the athletes experience in their lives. It may be 10 or 20 years – or even longer – until the study is completed, and there’s no guarantee it will be published then.
So, with all of this in mind, what does the research say we should experience as we become “older” endurance athletes? Here’s a partial shopping list of changes as revealed in some of the research:
- Declining VO2max
- Reduced maximal heart rate
- Decreased volume of blood pumped with each heart beat
- Lowered lactate threshold
- Less economical movement resulting in wasted energy
- A decrease in muscle fibers and strength
- Less effective and less abundant aerobic enzymes
- Reduced blood volume
- Loss of muscle mass
There’s more, but that’s enough to make you want to avoid birthday parties. Incidentally, not all of the research agrees on all of the above results of aging.
Which of these do I seem to be experiencing now? Is there anything that can be done to delay and reduce the negative changes? I’ll address that in my coming posts. Stay tuned.
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