What is it that I need to do to to remain sexually fit in the long run?

A healthy body will always leave you in a better sexual shape & energy. This can be achieved by keeping the calories intake as less as possible and Exercising regularly leads to good muscles flexibility, better blood flow in body and lesser fat leading to positive self-esteem which is obviously more attractive too! You could try multivitamin tablets which will enhance your health on generally. Keep away from vices as much as you can like alcohol, cigarettes, etc to keep yourself healthier. many couples find that sex becomes more intense and intimate as they age. It's not as simple as fewer hormones equal less sex. It's all about lifestyle: exercise, diet, sleep and a healthy engagement with life.