Wearing a good, well-fitting sports bra greatly helps reduce breast discomfort during high-impact exercise, such as running. Normal bras can be tight enough during physical exertion that they dig into your shoulders or sides, or they can be so loose that your breasts are bouncing, 

Keep in mind, though, that there is no one-size-fits-all sports bra. And it is good to change your sports bra after a couple of years of use, as they lose their stretch.

Types of sports bras: Sports bra design is mainly broken down into three categories: compression (stop movement by flattening breasts and pulling them close to the body), encapsulation (separating the breasts into cups and provide support through seaming, molding, or underwire instead of flattening them), and a combination of the two. Encapsulation bras provide more support.

A good sports bra is made from fabric that bounces back after being stretched to keep breasts securely in place. But, tehre is no fixed type of fabric. You have to check for yourself.

The best bra for DD+ cup sizes: Brooks Juno (straps that adjust in the front with Velcro, easy to adjust, gives support without uncomfortable underwire or hardware)

The best bra for C/D cup sizes: Champion Spot Comfort (easy to adjust and take off, gives cup definition, keeps breasts snug)

The best bra for A/B cup sizes: Brooks SureShot (tough material, provides more compression to control bounce)

The best bra for zero bounce for DD+ cups: Enell Sport (most support for larger cups)

The second best bra for zero bounce for DD+ cups: Nike Rival (very smooth material, provides gerat cup definition)