A wearable lactic threshold and entrainment exercise device (LTEExD) is described herein. LTEExD may assist subjects in improving athletic performance. Users adjusting their exercise regimen in real-time with the assistance of LTEExD often exercise more efficiently and perceive exertional status as feeling like a ‘second wind’. LTEExD collects physiologic data, and uses a signal analyzer to convert the data from the time domain to the frequency domain primarily utilizing fast fourier transform based spectral analysis to accurately determine certain physical variables. Variables are determined, integrated, and compared by the signal analyzer to determine whether lactic threshold has been reached and/or entrainment has occurred. LTEExD may wirelessly transmit variables to a remote display, where an observer is provided real-time feedback to self-guide adjustments to an exercise regimen to improve efficiency, perceive a ‘second wind’, improve sprint and endurance fitness levels, and improve overall competitive athletic ability.
