Why Testosterone Matters for Muscle Health in Older Men
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As men age, many notice they become weaker, slower, and lose muscle mass. This gradual decline, called sarcopenia, can make everyday activities harder and increase the risk of falls, dependency, and poor health. One of the key factors linked to this decline is a drop in testosterone, the main male sex hormone. But not all testosterone measurements are equal. New research from Copenhagen suggests that “calculated free testosterone” may be a much better indicator of muscle health than “total testosterone” in older men.
Total vs Free Testosterone – What’s the Difference?
Testosterone in the blood exists in two main forms. Most of it is bound to proteins such as sex hormone binding globulin (SHBG) and albumin. A small portion floats freely in the blood, ready to act on muscles and other tissues – this is called free testosterone. Calculated free testosterone is estimated using total testosterone, SHBG, and albumin levels. As men age, SHBG tends to rise, which means a bigger share of testosterone becomes bound and inactive. This can make free testosterone drop faster than total testosterone.
What the Study Found
Researchers measured hormone levels, muscle mass, muscle strength, and physical performance in 557 healthy Danish men aged 23 to 92. They looked at several indicators, including handgrip strength, leg extension power, and the 30-second sit-to-stand test, which counts how many times someone can rise from a chair in half a minute.
For older men, calculated free testosterone was linked to better scores in almost every measure – higher muscle mass, stronger grip, more leg power, and better performance in the sit-to-stand test. Total testosterone, on the other hand, showed weaker and less consistent links. In fact, for older men, total testosterone was only clearly linked to leg power after adjusting for body fat. For younger men, the connections between testosterone and muscle performance were less clear, and sometimes even the opposite of what might be expected.
Why This Matters for Health and Fitness
These findings suggest that in older men, calculated free testosterone may be a more reliable marker of muscle health than total testosterone. This is important because most routine blood tests only measure total testosterone. If doctors rely on that alone, they may overlook older men whose total testosterone looks “normal” but whose free testosterone is too low for optimal muscle function. For people trying to maintain independence and strength as they age, this distinction could be crucial in identifying who might benefit from targeted exercise or medical support.
Practical Steps to Support Testosterone and Muscle Health
Even without advanced hormone testing, there are everyday actions older men can take to protect muscle strength and function:
- Stay physically active – Resistance training, like lifting weights or bodyweight exercises, helps maintain muscle mass and stimulates testosterone production.
- Focus on leg power – Exercises that build both strength and speed, such as squats or step-ups, support mobility and independence.
- Maintain a healthy weight – Excess body fat can lower free testosterone levels, while being underweight can also weaken muscles.
- Get enough protein – Aim for a protein source at each meal to give muscles the building blocks they need.
- Prioritize sleep – Poor sleep can reduce testosterone production and slow muscle recovery.
- Manage stress – High stress can disrupt hormone balance and sap energy for physical activity.
When to Talk to a Doctor
If an older man notices rapid muscle loss, weakness, or a big drop in physical ability, it may be worth discussing hormone testing with a healthcare provider. Asking about free testosterone or calculated free testosterone can give a clearer picture than total testosterone alone. If levels are low, a doctor might suggest further evaluation, lifestyle changes, or, in some cases, testosterone replacement therapy. However, hormone therapy is not suitable for everyone and should be considered carefully with medical guidance.
The Bottom Line
Muscle health is key to staying active, independent, and healthy as we age. This new research shows that for older men, calculated free testosterone – not just total testosterone – is strongly linked to muscle strength, power, and performance. By focusing on the right measurements and combining them with smart lifestyle choices, it is possible to slow down the effects of age-related muscle loss and enjoy a better quality of life for longer.