Fitness trackers can help in managing chronic diseases by enabling users to monitor their physical activity levels, heart rate, and sleep patterns, which are crucial data points for managing conditions such as heart disease, diabetes, and obesity. They can encourage a more active lifestyle and provide valuable insights for healthcare providers. However, it's important for users with chronic conditions to choose trackers that are tailored to their specific health needs and to consult with healthcare professionals about how to best integrate the use of these devices into their management plan.