Refuel with carbohydrates (fruit, vegetables, bread, cereal, etc.) within one half hour after an exercise session - whether swimming, weight training, running, or ??
Bone density loss - bone density reaches its maximum by about age 20, and starts to erode as we age from that point. This is a concern for many women, who typically have small frames to begin with (Men are not exempt, but this is less of of a problem for them .). This process (Osteoporosis) cannot be stopped or reversed, but it can be slowed. First, it is prudent to build up bone density before age 20 by taking plenty of calcium (1200 mg/day), then maintaining an adequate amount (800 mg) for the rest of your life. In addition, studies show that weight-bearing exercise (especially weight training) contributes significantly to slowing bone density loss.
Weight training for women has a number of benefits: 1) it builds/maintains strength for daily activities, 2) increases metabolism for more efficient weight control, 3) increases muscle tone for improved appearance (for those few of us who care), and 4) it slows the aging process, among a host of other benefits. It should be noted that there are still women who believe in the myth that weight training will make them grow big muscles. It is the male hormone, testostrone which allows men to be more muscular - women have some, but not much). For women to achieve the same results, they would have to take drugs, or be more-or-less genetic oddities. In addition to genetics, there are two other factors to consider. If a muscular person stops exercising, the muscle atrophies - shrinks. Furthermore, by training with high repetitions (>10), muscle endurance and tone is improved, but does not significantly increase in size.
Weight control, specifically fat loss, is accomplished by long duration (30-40 minutes or more for untrained individuals) aerobic activities like walking, jogging/running, aerobic dance, riding a bicycle; but not swimming, which is otherwise an excellent exercise. At the start of an aerobic activity, both fat and carbohydrates are being burned. As the intensity increases, carbohydrates become the primary fuel source; however, if the activity remains at a low to moderate intensity for a longer duration, fat becomes the primary fuel source. Weight training is important in this process because fuel is burned (energy is expended) to a large degree in muscle tissue.
Any questions should be directed to the author of this publication. I understand that he loves to talk about this "stuff."