A quick test to try
Before you read on, try something. Stand on a clear patch of floor, cross your feet and slowly sit down on the floor without supporting yourself with your hands, knees or elbows. Then get back up the same way. If you feel unsteady on your feet, make sure there is something to hold on to nearby.
How did it go? Many people notice it is harder than they expected. Some need a hand, a knee or a bit of momentum. Others glide down and back up effortlessly.
What looks like a party trick was studied by researchers in Brazil in around 2,000 people aged 51 to 80. Anyone who got down and back up without any help scored full marks. Over the following years, a pattern emerged: the more points someone had, the longer they lived on average.
Behind the test lie strength, flexibility and balance. These very abilities are part of your biological age. Your chronological age counts the years since you were born. Your biological age describes the actual condition of your body, and that includes how much strength it still has available for you. But why are muscles so crucial here?
Muscles as a reserve: Why strength counts for so much as you age
From around the age of 30, the body slowly begins to lose muscle mass. At first you hardly notice. Over the decades, though, it adds up, and in later life the loss usually speeds up. Experts speak of sarcopenia when muscle mass and strength have declined so far that everyday life suffers.
Think of your muscles as a savings account. What you pay in during your younger years builds a cushion you can draw on later. If you go into old age with a large cushion, you can offset the natural decline for a long time. If you start with little, you hit your limits sooner: climbing stairs, carrying shopping or getting up out of a low armchair.
These limits have consequences. Weak muscles increase the risk of falls, and in old age falls are among the most common reasons people lose their independence. So strength determines not only how old you feel, but also how long you stay in charge of your own life.
Muscles as an organ: What happens in your body when you train
For a long time, muscles were seen mainly as the engine for movement. Today we know they can do more. When you contract them, they release messenger substances called myokines. These travel through the blood to other organs, where they act on metabolism, the immune system and even the brain.
Blood sugar is one example. Working muscles take up sugar from the blood and use it. If you have more muscle mass, you have a bigger store that helps keep your blood sugar in balance. Your bones benefit too, because they respond to the pull of the muscles and become denser.
In one respect, however, strength differs clearly from endurance. In a large comparative study, strength training did not measurably change the protective caps on the cells, the telomeres, whereas endurance training did. So strength affects your biological age through other pathways: reserve, metabolism and bones. Read more here (Article: Endurance).
That leaves the question of when it is too late for strength training. A study from the USA gives a surprising answer.
When 90-year-olds lift weights
In the late 1980s, a research team led by physician Maria Fiatarone ventured an experiment that many considered bold at the time. Ten frail nursing home residents, on average 90 years old, spent eight weeks specifically training their leg muscles, with weights that genuinely challenged them.
The result surprised even the researchers. On average, the participants' leg strength had almost tripled. Their thigh muscles had become measurably larger, and they moved much more steadily and quickly than before.
Larger studies show why this matters so much: in older people, exercise programmes reduce the number of falls by around a quarter, and programmes combining balance and strength training by around a third. And fewer falls mean fewer injuries, fewer hospital stays and more independence.
How much strength training do you need?
The good news: less than many people think. The World Health Organization recommends strengthening all major muscle groups (legs, hips, back, abdomen, chest, shoulders and arms) on at least two days a week. Analyses of large studies show that as little as 30 to 60 minutes of strength training per week is associated with a longer life expectancy. That is two to three short sessions.
You do not need a gym for this. Squats, lunges, push-ups against the edge of a table and forearm planks train your whole body using your own weight. Gardening or carrying heavy shopping bags counts too, as long as your muscles are noticeably working. A good rule of thumb: the last repetitions of an exercise should be hard but still doable with clean technique.
If you are just starting out, build up slowly. First learn the movement properly, then increase the repetitions, and only after that the weight.
For your biological age, what counts is not how much you lift, but that your muscles are challenged regularly.
Where you stand on strength
How often you specifically train your muscles is one of the questions in the BioAge test. Together with the other questions, it produces an estimate of your biological age and an overview of where you have the most to gain.
Frequently asked questions about strength training and biological age
Do I need more protein if I do strength training?
Muscles need protein as a building material. The German Nutrition Society (DGE) recommends that adults get around 0.8 grams per kilogram of body weight per day, and around 1 gram from the age of 65. If you train regularly, you can make good use of a little more. Read more here (Article: Nutrition).
When will I notice the first progress?
Often after just a few weeks. In the beginning, it is mainly your nervous system learning to control the muscles better, which is why strength increases quickly. Visible muscle growth takes longer and usually only shows after a few weeks to months.
Does strength training make sense with high blood pressure or joint problems?
In most cases yes, often especially so. It is important to keep breathing calmly during the exercises instead of holding your breath, and to start with moderate loads. If you have known pre-existing conditions, talk to your doctor first.
Does strength training help with losing weight?
Above all, it helps you keep your muscles while losing weight, so that you mainly lose fat and not valuable muscle mass. The extra calories burned by having more muscle, on the other hand, are smaller than is often claimed.