As we age the ability to make vitamin D in the skin decreases. It is recommended that we take 400 to 800 international units of vitamin D daily. Major food sources of vitamin D are fortified dairy products, egg yolks, saltwater fish and liver. Bones become stronger and denser when demands are made on them and conversely, lack of exercise particularly as you get old may contribute to lower bone density. In weight-bearing exercise your muscles and bones work against gravity, e.g. jogging, walking, climbing stairs and football.
Resistance exercises are weight-lifting exercises.
Many daily activities and most sports involve both types of exercise. Some women experience side-effects and the HRT approach should be carefully discussed with a medical specialist.