There is a traditional view that humans demonstrate a notoriously high level of inter-individual variability in sweating. A review of the literature (Chapter 1) revealed that much of the individual variability in thermoregulatory sweating can be explained by the evaporative requirement for heat balance (Ereq) and that skin temperature is considered a powerful modulator of the sweating response, yet investigations to date had only examined this effect during non-steady-state sweating. Therefore, a retrospective analysis was carried out (Chapter 2) on over 140 observations of 2-h treadmill walking, across a range different air temperatures and exercise intensities, to determine how much individual variability in whole-body sweat rate (WBSR) is described by variation in Ereq alone and to investigate whether mean skin temperature described any residual variability. Findings showed that even in situations where sweating efficiency is comprised, which is more representative of most field settings, Ereq explains much (~80%) of the individual variability in whole-body sweat rates. Additionally, despite its well-established influence on the sweating control system, skin temperature did not explain any of the residual variability in WBSR independently of Ereq. This finding in conjunction with those from the literature review suggested that the influence of skin temperature may be isolated just to the initial phase of the sweating response. To examine this theory, a laboratory-based study was conducted (Chapter 3), designed specifically to characterize the independent influence of skin temperature on thermoregulatory sweating during both steady-state and non-steady-state sweating. Results showed the large differences (4-5˚C) in skin temperature changed the physiological control system, yet no detectable differences to cumulative whole body sweat losses, even after just 45 minutes of exercise, were evident.