With the Sun as your ruler, the area Leo natives need to protect is their heart. Your sign loves to be active and eat healthy, so that's half the battle.
Staying positive also helps, as does reducing stress with meditation, tai chi, yoga or something else you love. Staying heart healthy also means engaging in relationships that are truly loving and supportive.
If someone's undermining you, you're not going to be happy. If someone's cruel, same thing. Only those who love you for who you are will help keep this vital organ functioning well.