According to Reuters, a study published in Occupational and Environmental Medicine suggests that while sleeping for only a few hours at night can increase risk for heat fatigue when working in the heat, a quick post-lunch nap may be the solution to the problem. Study subjects were observed under four different conditions ranging from a normal night of sleep with no nap, to four hours of sleep with a short afternoon nap. Those who did not take a nap and had restricted sleep had a higher core temperature when asked to walk for 40 minutes in a heated room. Those who did take a nap reported less afternoon sleepiness and felt less overheated and fatigued. More research is needed to confirm these results, but it seems that a short afternoon siesta can be beneficial for vigilance and helping people feel less fatigued.