When you do high-intensity interval training (and if you’re not, you should be!), follow a 2:1 work-to-rest ratio, such as sprinting one minute followed by 30 seconds of recovery. [Tweet this secret!] According to several studies, the most recent out of Bowling Green State University, this formula maximizes your workout results. The BGSU researchers also say to trust your body: Participants in the study set their pace for both running and recovery according to how they felt, and by doing so women worked at a higher percentage of their maximum heart rate and maximum oxygen consumption than the men did.
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.”