Do workouts really need sports bras? yes, definitely, and please remember not to engage in any physical exercises without arming yourself with a proper sports bra. In fact, a woman's wardrobe must include a number of sports bras for use in activities that demand considerable levels of body movements.
Sports bras are meant to support and protect: reduce the amount of breast movement and keep it in place while engaging in physical activities like brisk walking, jumping, kicking, or running, especially during workout sessions. Never wear wear a fashion bra when you do workouts or any body activity aimed to lose weight.
Finding the right sports bra may require you to measure your chest size by wrapping a tape measure under your arms and and above your breast, rounding it off to the next even whole number. Then combine it you cup and waist size. Check if it it for low, medium or high impact activity. This information can be found in sports bras labels. Bear in mind, too, that you need to choose the best style that fits you: compressed (tends to tighten in A and B cup sizes), under-wired (for full beasts), or encapsulated (to provide natural shape for larger sizes).
Never do workouts without proper support. You may want your breasts to look great and sexy but don't compromise it with protection and comfort. You will surely find the best sports bras for your age and size online.