Is your gym attire setting you up for health problems?

Kenya's fitness boom is fueled by activewear designed for stretch, sweat, and shine. However, little consideration is given to the actual materials found in these fabrics. By 7 a.m. on Saturdays, Riverside Square in Nairobi's Westlands neighborhood is already bustling with activity. Hundreds of individuals don matching leggings and sports bras, clip water bottles to armbands, and prepare for a run that often concludes with coffee.

This was a routine for four friends four years ago, but now it's We Run Nairobi, the country's largest free running community. On its busiest days, it attracts over 1,200 participants through Nairobi's upscale areas. Running clubs represent just the most visible facet of a broader movement. Fitness challenges spread through TikTok and Instagram, while step-count groups coordinate targets via WhatsApp and the fitness app Step-Up.

Gyms, once frequently empty, now have lengthy waiting lists. At the Nairobi Bariatric Centre, a clinic that once struggled to attract patients, doctors now treat around 10-15 individuals daily. This shift is marked by a concerning trend: nearly 90% of Kenya's cosmetic surgery patients are women. Kenya, once a nation where carrying extra weight signified prosperity, is currently experiencing a wellness crisis.

The World Health Organization's Kenya office reported in 2025 that noncommunicable diseases account for 41% of deaths and half of all hospital admissions. At the heart of this transformation lies the literal fuel powering it all: the very fabrics of the activewear worn by these fitness enthusiasts.