Study to Explore How Core Temperature Reduction Influence Health

The goal of this clinical trial is to learn if cold water drinking could promote body composition and further extend healthy lifespan in Chinese older adults. The main questions it aims to answer are: 1. Does cold water drinking lower the body fat percentage? 2. Will cold water drinking positively extend lifespan in a long-term Researchers will compare cold water intervention group to a control group (drinking 37℃ water instead) to see if cold water drinking works to promote health and slow down ageing process. Participants will: 1. Drink 4℃ or 37℃ water 4 times (9a.m., 12p.m., 15p.m., 18p.m.) every day for 6 months. 2. Visit the institute and health checkup department for tests and checkup at baseline, the end of the 3rd month, and the end of 6th month.