Bentall was eventually referred to a sports injury specialist who diagnosed him with a stress fracture in the hip and low vitamin D levels. He wasn’t given a bone scan though. It wasn’t until later when he enrolled in a study on male cyclists that he was able to get one done, and it showed he had low bone mineral density in his spine, a classic symptom of RED-S in male cyclists.
Challenges of Diagnosis
On why warning signs are often missed, Dr. Nicky Keay, a sports and dance endocrinologist and member of British Association Sport and Exercise Medicine, told OTW, “The obvious clinical sign of RED-S in female athletes/dancers is often amenorrhoea. In men the equivalent will be loss of libido and decreased early morning erections. Furthermore, unlike running, cyclists will not present with stress fractures. So suboptimal bone health may not be recognized.”
“Therefore, early identification of athletes at risk of developing health and performance adverse consequences is an important strategy,” she said.
Bentall noted in British Journal of Sports Medicine that he, like probably a lot of other male athletes, had thought that RED-S was a female phenomenon and was associated more with eating disorders. When they have a healthy relationship with food, they don’t even consider that they might possibly at risk for RED-S.
It is not always related to an eating disorder or weight loss, however. The under fueling can happen accidentally and in some cases it is more about timing of meals than how much you eat in a given day. Not properly fueling up before exercise is enough to cause energy deficiency.
Another challenge in diagnosing RED-S is identifying the cause of low testosterone, because while it can be a symptom of LEA it can also be a symptom of a too high training load.
Getting an accurate diagnosis of LEA in male cyclists is further complicated by the fact that unlike in runners a stress fracture is not always an early warning sign of poor bone health caused by low EA. In addition, cyclists are already at risk of poor bone health because of the non-weight bearing nature of the sport.
What the Research Says
Dr. Keay has a particular interest in how RED-S affects the cycling community.
In “Low energy availability assessed by a sport-specific questionnaire and clinical interview indicative of bone health, endocrine profile and cycling performance in competitive male cyclists,” published in British Medical Journal Open Sport & Exercise Medicine, she and her co-authors used a combination of a sport-specific questionnaire and clinical interview (SEAQ-I) and dual energy X-ray absorptiometry (DXA) bone mineral density and body composition scans and blood tests for endocrine markers to evaluate 50 competitive male road cyclists.
According to the data collected, those cyclists identified as having LEA from the SEAQ-I had lower lumbar spine bone mineral density (BMD) than those with adequate EA. Low EA was observed in 28% of the cyclists. Low lumbar spine BMD was found in 44% of cyclists. EA was the biggest determinant of lumbar spine BMD Z-score (p < 0.001). Among those cyclists with the low EA, lack of previous load-bearing sport was associated with the lowest BMD (p = 0.013).
Low vitamin D and testosterone levels were also associated with chronic low EA. LEA was also found to affect cycling performance. In the study, cyclists with chronic LEA were underperforming.
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