I was listening to the radio on my way to work earlier this week and a story on National Public Radio caught my attention. A retired scientist who also happens to be a life-long cyclist noticed he and his friends didn’t seem to be aging the same way their non-cyclist peers were. Not in the “Cocoon” way, but rather that they weren’t experiencing as many illnesses and as much physical decline as they anticipated. Being a scientist, he naturally got together with other scientists and designed a study to figure out why.
The Crux of the Findings
I went and found the actual study by Duggal, et al. and, I have to admit, a good deal of the science was above my pay grade. What I learned from the study, some phone calls, and more reading is that their findings focus on a potential protective effect exercise could have on the function of the thymus, a key component of the endocrine system that plays a large role in the immune system. The thymus is active in the creation of T-cells, which are crucial to the adaptability of the immune system as you encounter new antigens. The thymus is largest and most active up to and through adolescence, and then it starts to atrophy. As humans age, the thymus undergoes “organ involution” as the tissue is gradually replaced by adipose tissue (fat).
The researchers compared the immune systems of 125 lifelong cyclists ranging from 55-79 with age-mated non-athletes and with a group of younger non-athletes. Compared to the elder non-athletes, the masters cyclists showed significantly less decline in thymus function, suggesting they had increased protection against illnesses and decreased chronic inflammation (ageing is associated with “inflammaging”, or an increase in circulating inflammatory cytokines). Essentially, the masters cyclists had “a younger person’s” immune system. Two thumbs up!
Why Cycling, Specifically?
While including cycling in the radio headline grabs attention, the title of the study refers to “high levels of physical activity”. The findings relate to masters cyclists because they were the ones studied, not necessarily because cycling is any better than running or swimming or other physical activity in terms of preserving thymus functionality as we age. This is another case where subsequent studies will certainly examine those variables.
I have my own – albeit biased – view as to why cycling is the fountain of youth.
Low impact – crashes notwithstanding, cycling is easy on the joints, particularly throughout the lower body (feet, ankles, knees, hips). There’s an old saying in orthopedics that “motion is lotion” for joints because it keeps synovial fluid – the lubricant for your joints – moving and working. And with cycling, all this joint movement comes without jarring impacts and high ground reaction forces with each step and jump. As we get older, there’s simply less wear and tear to cause pain and limit mobility.
Adaptable position – Dr. Andy Pruitt at the Boulder Center for Sports Medicine always used to say that “the body is adaptable and the bike is adjustable”, meaning you could almost always find a way to adjust a person’s bike fit – and help them adapt physically – in order to improve performance and/or keep them riding. We see this all the time. Fred Schmid, the 84-year-old CTS Athlete who keeps winning his age group at the US cyclocross national championships, has a pretty upright position on the bike. Gage Hecht, the U23 Pan-Am Cyclocross Champion coached by Jim Lehman, has a low and aggressive cycling position. Some cyclists move to recumbents and trikes, but they keep pedaling.
Gears – Mechanical assistance is a key to keeping cycling enjoyable from childhood through old age. When you have power you can leverage it with big gear ratios. When you’re not as strong – at any age – you can break the work into smaller chunks by using lower gears. That said, billions of people – old and young – around the world ride their whole lives on bikes with only one gear.
The Problem With This Aging Study
Correlation is not causation. Just because masters cyclists showed different immune system function doesn’t mean the cycling is what caused the differences. To be clear, the researchers in this study aren’t necessarily saying it is, either. Their results do, however, support earlier research that shows physical activity slows the physical, mental, and even mental, decline associated with aging.
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While I firmly believe exercise plays a huge role in longevity and long-term quality of life, I also recognize it’s difficult to say that sport is what keeps older athletes healthy. To some extent it could be the opposite; good genes and other healthy lifestyle habits may mean some fortunate people are physically capable of being athletes into older ages. Ultrarunning provides some evidence for this. If running were inherently damaging to knees, there would be no ultrarunners over the age of 40. Yet, go to any ultramarathon and you’ll see the 40+ age group is not only huge, but they often place in the top 10 and sometimes even win! It’s not that ultrarunning is beneficial for your knees, but rather that runners who are genetically well suited for running, take care of themselves, and don’t suffer accidents, don’t get injured and keep running.
Personally, I’m banking on a little bit of both. I’m hoping my genes and healthy lifestyle habits will enable me to be an athlete for the rest of my days, and I’m hoping that staying active and continuing to train will protect me or slow the progression of age-related performance declines.
Who’s with me?!
CEO/Head Coach of CTS
Duggal, Niharika Arora, et al. “Major Features of Immunesenescence, Including Reduced Thymic Output, Are Ameliorated by High Levels of Physical Activity in Adulthood.” Aging Cell, vol. 17, no. 2, 2018, doi:10.1111/acel.12750.
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