Cycling can keep you young


New research suggests that exercise such as cycling can prevent many of the negative consequences of ageing. Ageing has been shown to be accompanied by a decline in immune function, referred to as immunesenescence. This is characterised by an increaesed risk of infection as we age. The study discussed here concluded that cyclists preserved muscle mass and strength while also showing more stable cholesterol and body fat levels. Men also sustained high testosterone levels. Importantly, recent studies have shown that IL‐7 is produced by human skeletal muscle (Haugen et al.,2010), providing a possible explanation for raised levels in the cyclists who did not lose muscle mass with age (Pollock et al., 2015).

cycling & ageing image. Naas Physio Clinic

The authors compared the health statistics of 125 amateur cyclists with a comparison group of 75 age-matched older adults and 55 young adults not involved in regular exercise. The male cyclists in the study had to be able to cycle 100km in 6.5 hours while women had to cover 60km in 5.5 hours.

Cycling & Ageing – Immune Effects

One of the primary immune organs in the body is the thymus gland which sits in the front of the neck. This has been shown to shrink in early adulthood and this process accelerates rapidly after the age of 40 thus causing a reduction in the number of  immune cells produced by the thymus gland called T-cells. Interestingly, the degree of reduction in thymic gland output has been proposed as a determinant of mortality in older adults

The researchers found that the thymus of older cyclists were producing T-cells at a similar quantity to young individuals. Compared with their less active counterparts, the cyclists had significantly higher serum levels of the thymoprotective cytokine IL‐7 and lower IL‐6, which promotes thymic atrophy. The authors concluded that many of the immune impairments witnessed in the elderly may be driven by reduced physical activity rather than being attributed to ageing alone.

“We show here that the effect of maintained high‐level physical activity on T‐cell subset distribution is profound.”

Cycling & Ageing – Decreased Inflammation

Another feature of human aging is an increase in circulating levels of pro‐inflammatory cytokines (IL‐1β, IL‐6, TNFα,) termed Inflammaging. Research suggests an increased risk of age-related disease and mortality due to this process.

The problem with associating all of these changes to the ageing process is that it does not consider other confounding variables such as the decreased exercise levels in the elderly population. It may be that part of the changes attributed to the ageing process may in fact be a consequence of lifetyle factors such as a lack of exercise and resultant weight gain and cardiac dysfunction. As fat cells are known to store inflammatory chemicals, this may also provide an explanation for an increase in inflammatory markers as we age. Regular physical activity in older adults has been associated with lower levels of pro‐inflammatory cytokines such as IL‐6, TNFα (Gleeson et al., 2011) and increased T‐cell (thymus cell) proliferation (Woods et al., 1999)

“We conclude that maintained physical activity into middle and old age protects against many aspects of immune aging which are in large part lifestyle driven.”


Ref: Arora Duggai et al. (2018). Major features of immunesenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood. Aging Cell Journal.

Sudden Increase in Training Intensity Increases Risk of Injury

A Sudden Increase in Training Intensity Increases Injury Rates


As the evenings are becoming brighter people are turning their thoughts towards getting outdoors for exercise. It may even be time to get the running shoes on again. At this time of year, people tend to present with overload type injuries induced from a sudden increase in exercise intensity.

A recent study published in the British Joournal of Sports Medicine suggests that a sudden increase in training intensity is associated with a significant increased injury risk. This research showed that a very- high 2-week average acute:chronic workload ratio (≥1.54) was associated with the greatest risk of injury (28.6% injury risk). In other words, an increased in training intensity above the normal for that person is associated with a significant increased injury rate of almost 30%. This research was performed in professional athletes but it is possible that the average person may be at even greater risk of increasing injury risk due to a lack of muscular adaptation & conditioning. The takehome message is to increased the intensity gradually. Many an exercise plan has been cut short due to injury. Adequate planning is key to preventing this from happening.

Hip & Knee Arthritis

Low Prevalence of Hip and Knee Arthritis in Active Marathon Runners.

A frequent comment from patients is that they avoid running as they are fearful that this will cause “wear & tear” of the knees or hips. A consequence of this ‘loading equals degeneration’ mindset is that there is a general perception that running will give rise to early arthritis. This would appear to be logical when one considers the “pounding’ of the joints induced from long distance running such as occurs during a marathon. The evidence on this topic; however, does not necessarily back up this theory.

Several studies have show that distance runners do not have a higher incidence of hip & knee arthritis than non-runners. A recent study by Ponzio et al. (2018) found that marathon runners had a lower incidence of hip and knee arthritis when compared with the general population. Arthritis prevalence was 8.8% for the marathon running group. This was significantly lower than the prevalence in the matched U.S. population, which was 17.9%. The avaerage age of the study participants was 48 years of age and the group ran an average of 36 miles weekly. The non-marathon running group were matched by age, sex, body mass index (BMI), and physical activity level. The authors concluded that there was no significant risk associated with running duration, intensity, mileage, or the number of marathons completed.

It may be that the straight line nature of long-distance running is less likely to cause injury to the hip or knee when compared with other forms of exercise such as rugby, soccer and gaelic which tends to involve a lot of pivoting and change of direction. There is a also a greater risk of a trauma which can cause injury to the cruciate ligaments or knee cartilage. Individuals who suffer from a cruciate or cartilage injury to the knee have been shown to suffer from much higher rates of arthritis as they age.


Destruction and loss of articular cartilage is a central feature in most forms of arthritis. Recent research has suggested that the cyclic loading and unloading of cartilage induced from walking and running may actually be beneficial to joint cartilage. The cyclic movmenent has been shown to help maintain healthy cartilage in laboratory studies. Part of the reason for this is that the movement stimulates increase blood and nutrient supply to the tissues hence keeping them healthy. This may be one reason why striaight line activites may give rise to healthier knees in the long-run when compared to actiivties involving pivoting or potential trauma. This may be one reason why the runners in this study fared better than athletes in the comparison group who may have participated in riskier sports than were associated with an increased risk of knee injury.

Does Body Fat Impact on Arthritis Risk?

There are several factors that drive joint degeneration. General inflammation is one such cause. Fat cells have been demonstrated to increase the production of inflammatory markers in the body. Fat cells (adipocytes) contain self-defensive macrophages (immune cells) which have been shown to produce cytokines (pro-inflammatory proteins). Therefore, the greater the fat percentage, the greater the inflammation in the body. Runners, by having a lower body fat percentage, would generally have lower inflammatory markers in the body. It is also likely that frequent runners are more health conscious and therefore may consume a healthier diet and avoid other poor health choices such as smoking and drinking alcohol excessively.

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