If we have long thought that childhood or adolescence determined our future health, recent science is shaking up these certainties. According to a study published in 2025 in Annals of Medicineit is the decade from 36 to 46 years old which proves to be the most decisive for preventing chronic diseases and strengthening quality of life. A time when the body and mind react particularly to the behaviors adopted – and where every choice counts.
The most crucial period for health
In a video relayed on Instagram, health expert Dan Go highlights the importance of this age group: “Habits formed between the ages of 36 and 46 have more impact on future health than those in any other decade.. The Finnish study carried out at the University of Jyväskylä followed several hundred people over more than 30 years, analyzing mental and physical health and risky behaviors such as smoking, alcohol and inactivity.
Result: the cumulative effect of bad habits becomes noticeable from the age of 36. Smoking mainly affects mental health, inactivity reduces physical health, and excessive alcohol consumption deteriorates both. The study concludes that although the relationship is likely bidirectional – poor health may encourage some addictions – adopting healthy habits at this age is crucial to limiting long-term damage.
Healthy habits: the key to prolonging life
Research from the Harvard TH Chan School of Public Health confirms that maintaining a balanced diet, engaging in regular physical activity, maintaining a healthy weight, limiting alcohol and avoiding tobacco in midlife significantly increases the years lived without chronic diseases. For women, adopting four or five of these habits at age 50 allows them to live an average of 34.4 additional years in good health, compared to 23.7 years for those who follow none. For men, the gap is 31.1 versus 23.5 years.
These figures demonstrate that it is never too late to change your lifestyle and that midlife can be the most effective period for consolidating your health and preventing physical and mental decline.
Focus on priorities
The study also highlights the importance of targeting smoking, alcohol and a sedentary lifestyle from your 30s to maximize benefits. Although childhood and the twenties remain important for personal development, the thirties and forties represent a strategic time for building a lasting foundation of health and longevity.
As Dr Tiia Kekäläinen, lead author of the Finnish study, recalls: “Adopting healthier habits in midlife also has benefits for older adults.” In short, every choice counts: the 36-46 decade could well be the most important decade of your life to stay in good health.