2.7. Calculations 
dehydration
DEHYDRATION
Sample size was calculated based on a pilot study with N = 8 that compared the physiological effects of these two methods of dehydration (Ethical approval number: H14/149). That study found PV to decrease by an average of 5.1% with exercise-induced dehydration, versus 11.8% with passive heat-induced dehydration. The SDwithin was 7.1%, so N = 11 was calculated to provide 80% power for detecting a different PV response at α = 5%. This was larger than the sample indicated by the power analysis of the only similar previous study we were aware of [Total energy usage, carbohydrate oxidation, and fat oxidation were estimated using equations derived from Weir [