High-intensity indoor cycling classes carry a “significant risk of kidney damage” – especially for first-time participants – according to a report in the American Journal of Medicine.

The study claims that indoor cycling classes – which simulate climbing hills, cycling on flat roads and include sprint cycles – may result in rhabdomyolysis, a condition where severe muscle trauma causes muscles to break down and release myoglobulin into the bloodstream; and has been termed Spin Class-Induced Rhabdomyolysis.

The syndrome, typically found in victims of a crush injury – such as a result of a car crash – can lead to serious complications, including kidney failure.

“Risk factors for the development of rhabdomyolysis are related to the intensity of the  exercise, the conditioning of the participant, hydration, and body temperature, in addition to other potential contributing factors,” said the researchers.

“Physiology studies have demonstrated that during indoor cycling classes, significant numbers of calories are burned, fluid losses are significant and body temperatures increase.”

The study presented details of three “unusual cases of exertional rhabdomyolysis”, each occurring in a patient who had taken part in their first indoor cycling class:

• In the first case, rhabdomyolysis developed following 15 minutes of a class.
• In the second case, it occurred in a young individual who exercises regularly.
• In the third case, the patient developed “biopsy-proven acute kidney injury” secondary to exertional rhabdomyolysis and required haemodialysis.

As a result of the study, the authors, from the Westchester Medical Centre in New York, recommend a set of guidelines be set up for indoor cycling.

Reference

Brogan, M., & Ledesma, R., Coffino, A. & Chander, P. (2018) Freebie Rhabdomyolysis: A Public Health Concern. Spin Class-Induced Rhabdomyolysis. 130(4), pp.484-487. DOI: https://doi.org/10.1016/j.amjmed.2016.11.004