Figure 1. Diurnal morning and evening variations of salivary cortisol in a 30-year-old obese male firefighter.

Panel AM: Diurnal variation in morning salivary cortisol showing a trendline of insignificant negative slope (R²=0.18). Panel PM: Diurnal variation in evening salivary cortisol showing a trendline of negative slope (R²=0.81). Subject characteristics: height 74 in, weight 289 lbs, body mass index 37 kg/sq m, waist-hip ratio 1.08, pulse 81/min, blood pressure 132/90 mmHg, pulse pressure 42 mmHg, years in fire service 12 y, hours worked prior to shift 48 h, hours worked in past 30 days 600 h.