How do you stay young and fit? Dr. Dr. Michael Despeghel, author of The BioAge Challenge, reveals in an interview what really matters.
If you want to stay young and fit, it’s in your own hands. “80 percent is about the quality and quantity of your lifestyle choices,” explains Dr. Dr. Michael Despeghel. The sports scientist and health expert, together with Prof. Dr. Karsten Krüger, has published the book The BioAge Challenge: You Determine Your Age! (GU). In this interview, he shares how he personally scores on the “BioAge” test and how sex, flossing, and friendships help reduce biological age.
In your new book The BioAge Challenge, you discuss biological age. Can you share how it differs from your chronological age?
Michael Despeghel: I achieved the highest score and can assume that I am ten years younger than what my passport states.
Biological age indicates how fit and healthy the body is, independent of birth date. Is a ten-year difference from chronological age the best possible outcome?
Despeghel: A difference of ten to twelve years is possible. However, it also depends on the age at which you take the test, as actual years of life play a role. Conversely, biological age can also be up to twelve years higher than chronological age. The problem is that this is the case for many people, with serious consequences: In Germany, we could see 40% fewer cancer cases and 50% fewer cardiovascular diseases. This could be achieved if more people followed the basic principles: maintaining a normal body weight, compensating for lack of physical activity, avoiding smoking, and paying attention to the quality and quantity of their diet. Currently, not even 30% of people achieve this. Meanwhile, experts are exploring how people can live beyond 100 or even 110 years—using advanced methods like cellular structure modifications, oxygen tents, or blood treatments. In my view, though, it only makes sense to consider such things once the fundamental lifestyle habits are in place.
How much of biological age is determined by genetics, and how much by lifestyle?
Despeghel: Genetic predisposition accounts for less than 20 percent. The remaining 80 percent comes from the quality and quantity of one’s lifestyle choices. This is a crucial point because it means everyone has the power to make a change at any time. The goal is not just to increase lifespan but, above all, to improve life quality. For people in their 70s or 80s, for example, this means maintaining mobility in daily life and being able to take care of personal hygiene independently. Aging is only enjoyable if you can take care of yourself. The chances of this are significantly better when lifestyle choices are optimized.
Your book includes a test to determine biological age. You ask questions about sexuality and flossing. Do these factors really help extend life?
Despeghel: A fulfilling sex life has a positive impact on the immune system. Everything that brings happiness and satisfaction benefits it. During sex, endorphins and the “bonding hormone” oxytocin are released. The immune system is crucial in fighting cancer, as it detects and eliminates toxic cells that form daily—especially as we age. So, sex is a great way to train the immune system.
Flossing, on the other hand, is about cleaning between the teeth—something a toothbrush alone cannot do. Otherwise, microinflammations can develop, which do not remain confined to the mouth but can spread into the vascular system. If there is chronic inflammation in the mouth, the risk of stroke is four times higher, and the risk of type 2 diabetes increases eightfold. This can be prevented by using dental floss daily or, even better, interdental brushes.
Nutrition is another crucial factor in staying fit. What should people consider?
Despeghel: A key focus should be an anti-inflammatory diet that doesn’t constantly stimulate blood sugar metabolism. One important approach is to have meal breaks. I recommend intermittent fasting, ensuring long intervals between meals.
Another essential factor is the balance of macronutrients: carbohydrates, proteins, and fats. Protein is particularly important: People under 50 should consume 1.2 grams of protein per kilogram of body weight daily, while those over 50 should aim for 1.5 grams. This can come from dairy products, but also from legumes, whole grains, fish, and meat.
When it comes to carbohydrates, focus on complex ones that are digested more slowly, such as those found in whole grain products. Healthy fats play a crucial role as well—especially omega-3 fatty acids, which help reduce inflammation. Good sources include walnuts, hazelnuts, almonds, flaxseed oil, rapeseed oil, olive oil, and salmon. Additionally, aim for 120 grams of fruit and 500 grams of vegetables per day.
Implementing these dietary habits requires effort. You need to engage with the topic and create a structured approach to incorporate these changes into daily life. But it is absolutely achievable.
The same applies to exercise. You provide tips and exercises for strength, endurance, and mobility. Are mobility exercises often neglected in traditional workout routines?
Despeghel: Yes, absolutely. When working out on machines in a gym, flexibility is often overlooked from a sports medicine perspective. However, it can be trained with exercises like balancing, standing on one leg, or touching the floor with your fingertips.
How do lack of sleep and excessive stress affect the aging process?
Despeghel: The immune system recovers at night, and stress hormones are reduced through sleep. The sympathetic nervous system—the “power nerve” that keeps us active—is dialed down, while the vagus nerve, which promotes relaxation, takes over. This shift allows the release of regenerative hormones that are crucial for cells, the brain, and mental health. The body needs about eight hours for this process. If this time is consistently lacking, the immune system is weakened and becomes less effective. The good news: Poor sleep can be compensated for with more sleep on weekends, for example.
For restorative sleep, avoid blue light from screens (smartphones, computers, tablets, TVs) two to three hours before bedtime. Intense exercise and a heavy meal in the evening should also be avoided. The bedroom should be dark, with a temperature around 18 degrees Celsius. Ideally, wake up naturally without an alarm clock and avoid scheduling stressful tasks first thing in the morning.
You also emphasize the importance of social connections in staying young and fit.
Despeghel: This is a crucial factor. The bonding hormone oxytocin plays a role here as well. Positive relationships with others foster a sense of connection and security, which in turn is perceived as relaxation. Security and relaxation, in turn, support the immune system.
