The construction and performance details of a simple and economical bicycle ergometer for performance of controlled recumbent exercise incident to human physiological experiments are reported. Bicycle sprockets are geared by a chain drive to the shaft of a 6‐volt automotive generator, which has been transformed into an eddy current dynamometer, suitably mounted on the chassis via separate external bearings. This permits free forward rotation of the external casing and measurement of the downward thrust of a torque arm (welded to the casing) on an overhead‐suspended spring balance. Absorbed power (work required to operate the pedals) is varied electrically by passing a 110 ac power source through variable voltage and stepdown transformers (output range selection 0 to 20 v) and a rectifier into the generator. At rotational speeds of 40 rpm (metronome timed) the work range may be selected from 340 to 5741 ft‐lb per min, with increments as low as 42 ft‐lb. The apparatus provides 95% linearity through the 360‐deg cycle at rotational speeds of 30 to 60 rpm in a work range of 340 to 5100 ft‐lb per min.