How sport makes us younger

When assessing the effect of exercise on age, the first question is whether and how age can be quantified. While the chronological age of an individual can easily be determined, it is a challenge to measure the biological age. Estimates are possible by external appearance and physical activity. The length of telomeres is considered a further biomarker of ageing.

Telomeres are segments of DNA at the ends of chromosomes that do not carry genetic information but play an important role in the stability of the coding segments. The DNA strand is shortened with each cell division. Elements of the telomeres are lost but the DNA segments carrying information remain protected. If the telomere length falls below a critical level, the cell stops dividing or switches to programmed cell death (apoptosis). This mechanism limits the lifetime of cells and at, the same time, counteracts uncontrolled growth.

During a person’s life span, the cells' telomere length becomes increasingly shorter, meaning that the balance between cell division and cell death shifts accordingly. As the number of dividing cells falls, there is a progressive loss of cells, which leads to the development of signs of ageing, such as declining physical and mental capacity for performance and regeneration as well as immune competence. Physical wear and tear and loss of compensation mechanisms also foster the development of diseases.

Telomeres can, however, also be extended. The enzyme telomerase, which is found in stem cells, germ track cells, bone marrow cells and tumour cells as a result of mutation, takes on this task. Nevertheless, its activity can no longer be detected in mature body cells.

The change in telomere length currently appears to be key in influencing the ageing process. It is now known that a sedentary lifestyle, smoking and obesity contribute to telomeres becoming shorter faster, while exercise seems to have a protective effect.

Exercise not only prevents lifestyle diseases such as obesity and high blood pressure, it improves physical and mental performance and health too. Moreover, it has come to be regarded as an important ally against the ageing process. It has been demonstrated that people who exercise regularly generally live longer and healthier lives.

It has also been proven on numerous accounts that although the length of telomeres decreases with age, it is greater in size in people who are physically active than in people who lead a lifestyle with little exercise. This effect seems to benefit middle-aged and older people in particular. Regular activity plays an important role in this respect. For example, no positive effect could be demonstrated for people whose physically active phase was more than ten to twenty years in the past.

Furthermore, the type of physical activity seems to be decisive. Although regular workouts alone have a beneficial effect on fitness, a study recently published by researchers at Saarland University Hospital showed that endurance and interval training can positively influence telomerase activity in immune cells and even contribute to their elongation. However, this effect could not be shown for weight training alone.

Regular exercise is undoubtedly healthy. It improves a person’s physical condition, keeps them fit into old age and is one of the cheapest and most effective preventive measures in the fight against a variety of lifestyle diseases. According to what we know today, endurance sports and aerobic interval training are particularly recommended. This can be supplemented with weight training in order to build up muscle.

In conclusion, it is becoming increasingly clear that an old proverb has lost nothing of its meaning to this very day – exercise is the best medicine.