How Does Heat Stress Affect Telomere Length? A Pilot Randomized Controlled Trial in Urban Bangladesh

Personal exposure to heat may be elevated above ambient temperatures if an individual is very active (which generates metabolic heat) or wears clothing that prevents cooling. Age can influence the consequences of heat stress. Older adults are at elevated risk of adverse impacts from heat stress due to their reduced ability to dissipate heat. Heat stress is particularly high among outdoor workers. South Asia has millions of bicycle rickshaw drivers, who use their muscles or battery power to pull hundreds of pounds of passengers and goods on modified bicycles. When manual rickshaw drivers rest to cool off, they reduce their already meager income. Heat stress not only threatens their livelihoods and thereby their right to an adequate standard of living but also their right to work, given that they have few employable skills other than manual labor. South Asia faces the greatest current and predicted loss in disability-adjusted life years due to heat stress, and heat stress is particularly strong in informal settlements. As such, the investigators plan to conduct this study in Dhaka, Bangladesh. The overall hypothesis is that driving a battery-powered rickshaw will reduce heat strain. The investigators will evaluate the impact of driving a battery-powered rickshaw on core temperature (primary outcome), telomere length, kidney function, heart rate, heart rate variability, sleep quality, self-reported thermal comfort, mental health, wellness, and fatigue (secondary outcomes).