In a time in which the age at which people retire is gradually increasing, a long and healthy career is becoming more important. This chapter describes the relationship between sustainable work ability, healthy living and cognitive functioning. It gives an overview of the global room for improvement concerning healthy living and provides the societal background on why lifestyle change is necessary in sustaining the work ability of aging workers. It describes the most frequently used behavior change theories, the current state of lifestyle intervention research and its many applications, which can be used in both private and professional settings. Furthermore, this chapter discusses different types of interventions, how they have been developed in practice, and how the results of offline research have been translated to web-based settings over time. These so-called eHealth interventions, with low cost and more personalized preventive care to improve individual lifestyle patterns are becoming increasingly popular with Human Resource departments to aid employers and employees in maintaining work ability over time.