Abstract: A heat-stress effect estimating device estimates an effect of a heat stress imposed on a subject by an ambient temperature of the subject. The heat-stress effect estimating device includes a storage unit and a calculation unit. The storage unit stores a correlation of at least an ambient temperature of a person and an outdoor air temperature with at least one index indicating an effect of a heat stress on a person. The calculation unit estimates a state of the subject in terms of the at least one index, based on the correlation stored in the storage unit, an ambient temperature of the subject at a predetermined time point, and a history of an outdoor air temperature up to the predetermined time point.

Abstract: Ratios of measured values of glucose, citrate, and cis-aconitate in a biological sample obtained from a subject to measured values of glucose, citrate, and cis-aconitate in a biological sample obtained from a healthy subject are calculated, and the glucose ratio, the citrate ratio, and the cis-aconitate ratio are used to evaluate and/or assess fatigue. Similarly, an isocitrate ratio, a succinate ratio, a malate ratio, and a lactate ratio are calculated, and these ratios are used together with the three ratios to evaluate and/or assess fatigue. This makes it possible to objectively and easily diagnose and evaluate fatigue.