This type of statement instantly creates tension in both your mind and your brain, Michael Gervais, Ph.D., says. "When we have hostile or negative thoughts, our brain responds by releasing a chemical that impacts mood.” Repeated negative thoughts can become toxic, as our immune system becomes compromised due to the over-activation of the fight-or-flight mechanism. “Chronic negative thinking creates such a hostile internal environment that we can find ourselves depressed, anxious, even physically weaker,” Gervais says. In reality, toning and tightening your thighs requires attention to diet, plus cardio and strength training. Include lunges, squats and step-ups two to three times a week for your best thighs.