1. Physiological changes with age

As people age, the body undergoes many changes:

Decrease in muscle mass and strength. Muscles gradually become less dense, which directly impacts physical activity and feelings of energy.
Slower metabolism. The body begins to process nutrients more slowly, which can cause fatigue.
Decreased hormone levels, especially testosterone and growth hormones, which are responsible for strength, endurance, and recovery.
Changes in the cardiovascular system. The heart and blood vessels function more slowly, and the body's ability to supply oxygen to the muscles decreases.
2. When people typically notice a decline in strength
On average, many people begin to feel changes after 35–40 years of age. Between 50 and 60 years of age, fatigue can become more pronounced, especially with physical exertion or long workdays.
It's important to remember that this is individual: lifestyle, diet, activity, and genetics greatly influence the rate at which these changes occur.
3. Signs of declining strength
Fatigue quickly with normal activity
Prolonged recovery after physical exertion
Decreased endurance and strength
Loss of mood and decreased motivation
4. How to slow down the process
Regular physical activity, especially strength training, helps maintain muscle mass.
Proper nutrition, including adequate protein, vitamins, and minerals, maintains energy.
Sleep and rest are key to the body's recovery.
Stress management - ​​chronic stress accelerates aging and reduces strength.
Medical checkups can help detect hormonal or cardiovascular changes early.

Bottom line: The feeling of declining strength with age is a natural process that begins in most people after 35 - 40 years of age, but its manifestations are highly dependent on lifestyle. You can maintain activity, energy, and endurance by taking care of yourself, eating right, exercising, and getting regular rest.