This paper reviews briefly the implications for the health, safety and performance of the competitive soccer player of two environmental Stressors: hot weather and time zone shifts, and considers how the adverse effects of each of these factors can be minimized. It is convenient to discuss the two issues separately, although in fact they are closely interwoven. Baseline core body temperatures show a marked circadian rhythm, and the joint impact of stress responses to hot weather and time zone shifts can be additive if not multiplicative.