Chronic stress at work is a public health problem increasing morbidity and mortality, especially in men. Among the men military populations, the firefighters of Paris (FFPs) are particularly exposed. To deal with this stress and to improve stress management is challenging. Psychological fitness is required to regulate emotions which improve effectiveness under stress and enhance recovery from stressful events. The heart coherence (HC) program uses feedback from a simple pulse sensor to reflect changes of the emotional/psychological state, and to learn how to reduce stress and stabilize emotions. Another kind of psychological fitness focuses on cognitive training to regulate emotions, with the use of techniques to optimize potential (TOP). The TOP consists of learning easy techniques in mental skills to improve cognitive-based problem-solving using respiration, relaxation, and visualization. Although never published in a peer-review journal, the procedure of TOP training is structured and standardized for individuals and groups, and is widely practiced in air traffic controllers, with apparently good effects.