After turning 40, the body begins to experience noticeable changes in metabolism, hormones, and immunity. To live healthily to 100 years or beyond, it's essential to maintain a scientific lifestyle: eat a balanced diet rich in fiber, limit sugar and unhealthy fats; exercise regularly with activities like walking, yoga, or swimming to keep muscles, bones, and the heart strong. Quality sleep and a positive mindset play key roles in slowing down the aging process. Regular health check-ups help detect and treat potential conditions early. Investing in your health after 40 is the foundation for long-lasting vitality and longevity.