In this lesson for Year 3 students, the teacher emphasizes the importance of leading a healthy lifestyle by highlighting five key steps: drinking more water, consuming more fruits and vegetables, being more active by turning off screens, choosing healthier snacks, and engaging in regular exercise. The lesson underscores the benefits of aerobic exercise for both the heart and body and encourages simple activities like walking and taking the stairs for incorporating exercise into daily routines. The importance of making healthier drink choices, particularly by opting for water over sugary beverages, is also stressed.