The New Paper How to stay healthy and fit in your 40s and 50s Regular exercise improves bone density and keeps the muscles around the joints strong. Add yoga to your routine to increase suppleness and strength. TNP FILE PHOTO Jan 18, 2021 06:00 am 40s In your 40s, you may start to experience some subtle midlife changes, such as having trouble sleeping or squinting to read small text. Here are the best ways to implement damage control in this phase of your life. Keep moving Your body will naturally slow down, but maintaining mobility is important to reduce the rate of bone loss and strengthen the muscles around the joints.