It doesn't matter how many pushups you can do in a minute if you're not doing a single one correctly. “There is no point in performing any exercise without proper form,” says Stokes, who recommends thinking in terms of progression: Perfect your technique, then later add weight and/or speed. This is especially important if your workout calls for performing “as many reps as possible” during a set amount of time. Choose quality over quantity, and you can stay injury-free.

Fluids: Fluid needs increase as women age. The reason: Kidneys become less efficient at removing toxins. “Drinking more fluids helps kidneys do their job,” Schwartz says. “Unfortunately, thirst signals often become impaired with age, so people are less likely to drink enough water and other fluids.” Rather than fret about how many glasses to drink, Frechman says, check the color of your urine. "It should be clear or very pale colored. If it becomes darker, you need more fluid.”