A study conducted by researchers at the University of Arizona found that washing hands with cold water is just as effective at killing germs as washing hands with hot water.
The study analyzed the effectiveness of different water temperatures in removing bacteria from hands. The researchers found that washing hands with water at a temperature of 15°C (59°F) was almost as effective at removing bacteria as washing hands with water at a temperature of 38°C (100°F), the temperature typically recommended for hand-washing.
The unexpected result challenges the commonly held belief that hot water is necessary for effective hand-washing, and suggests that cold water may be a more energy-efficient and cost-effective alternative for hand hygiene. The study also highlights the importance of evidence-based practices in public health and the potential for scientific research to challenge established norms and improve health outcomes.
Michaels, Barry & Gangar, Vidhya & Schultz, Ann & Arenas, Maria & Curiale, Michael & Ayers, Troy & Paulson, Daryl. (2002). Water temperature as a factor in handwashing efficacy. Food Service Technology. 2. 139 - 149. 10.1046/j.1471-5740.2002.00043.x.