Most mainstream (think government, doctor) exercise recommendations focus on cardiovascular exercise and often treat strength training as an afterthought.
Aerobic exercise (cardio) is important and has many benefits including strengthening and protecting the cardiovascular system, but resistance or strength training is the exercise of choice if a long life is what you are after. A 20 year study of 8 762 men ages 20 to 80 conducted at the Aerobics Institute in Dallas found that men with the highest levels of strength were lest likely to die from heat disease, cancer or any other cause. High levels of strength reduced the risk of death from all causes by 32% (50% from heart attack and 32 percent from cancer) compared to the weakest 1/3 of the group.
While this study focused on men, strength should conceivable benefit women even more as they are more prone to loosing strength as they age and more susceptible to injury due to falls often caused by lack of leg strength.
In addition to living longer being strong also improves quality of life by allowing you to move better and do more things later into life.
If you are already doing aerobic exercise, don’t stop, but be sure to add strength training to the mix. If you are new to working out be sure to consider resistance training as a key component to achieving and maintaining your health.