Exercise and Health

The growing realization that exercise doesn’t really help with weight loss can dampen the motivation to be active in many people — one reason why I advocate for decoupling exercise from the notion of weight loss altogether. Unfortunately, then, what I’m about to tell you may elicit a response of, “Oh, come on!” But keep reading, because the news isn’t all bad.

When I heard about a new study that concluded that being physically active in midlife doesn’t appear to prevent age-related cognitive decline in women, my first thought was, “No … that can’t be.” Then I read the actual study and thought, “Darn it!” It’s practically been gospel that staying active helps us stay sharp as we get older. I believed it, and I’m pretty sure I’ve given that advice to both readers and clients. The research backed me up — or so I thought.

But this new study, part of the Study of Women’s Health Across the Nation, did something that most previous research did not — it enrolled a diverse group of 1,718 women when they were 45 years old, on average, then followed up with them for 21 years. The women were asked about their activity habits — both “formal” exercise and other general household-type activity. Their cognitive performance was tested nine times. The researchers also factored in information about socioeconomic status, education level, chronic disease and health behaviors such as smoking and alcohol use.

“The main reason we did this study is that we wanted to explicitly study the relation between physical activity and cognition in midlife women,” said lead study author Dr. Gail Greendale, a researcher and professor of medicine at UCLA. “The overwhelming majority of observational research — research that does not treat people, but observes what they do and collects information — about physical activity and cognitive performance has been done in people who are, on average, 70 years of age.”

Greendale also points out that almost all of the research has been cross-sectional — looking at a single point in time — rather than longitudinal, which requires taking many measurements of physical activity and cognition over many years. “Results of these cross-sectional observational studies conducted in older people may not be applicable to younger individuals,” she said.

Not only that, but if I measured your cognitive health right now and asked you how much you were exercising right now, it doesn’t tell me as much as you might think. It doesn’t tell me how much you used to exercise, or how sharp you were a year — or 10 years — ago compared with now. Also, when someone has poor cognitive health and low activity levels, it becomes a chicken-or-the-egg situation. In other words, which came first? You might assume that low activity levels caused a cognitive health decline, but the reverse could be true, a phenomenon known as “reverse causation” in research-speak.  READ MORE/