Why does it feel like my body is falling apart at 40?!
- Head 2 Toe Osteopathy
- 4 days ago
- 2 min read
The body’s decline after age 40 is driven by a combination of cellular changes, hormonal shifts, and alterations in muscle, bone, and metabolic function that occur naturally with aging.
Cellular and Molecular Changes
Studies show that around the mid-40s, both men and women undergo significant biomolecular shifts affecting many systems in the body. These changes lead to visible and functional declines such as slower metabolism, reduced ability to recover from stress or injury, and reduced efficiency of metabolic and immune pathways. Many of these changes are not just related to menopause in women but are seen in men as well, indicating broader biological triggers.

Musculoskeletal Decline
Loss of lean muscle mass (sarcopenia) and decreased protein synthesis begin as early as the 30s and accelerate after 40.
Muscle strength, endurance, and flexibility decline, affecting coordination, balance, and increasing injury risk.
Bone density also decreases, predisposing individuals to osteoporosis and height loss.
Even with regular activity, muscle mass loss is inevitable, but inactivity worsens the problem and contributes to slower metabolism.
Metabolic and Hormonal Changes
After 40, metabolism naturally slows due to loss of muscle and changes in hormones such as testosterone, oestrogen, and growth factors.
The body burns calories at a slower rate, making weight management more challenging even for active people.
Hormonal changes also affect how fat is stored and used, impacting cardiovascular health and energy levels.
Cardiovascular and Pulmonary Function#
The heart and blood vessels stiffen, and the heart fills with blood less efficiently.
The lungs lose some elasticity and capacity, making vigorous exercise more difficult.
The risk of hypertension, heart disease, and reduced aerobic performance increases with age.
Height Loss and Bone Structure
By around age 40, most people begin to lose some height due to spine and bone changes. Osteoporosis risk increases as bone loss surpasses bone formation with age, leading to further decline in mobility and strength.
Cognitive and Systemic Changes
Cognitive function can begin to decline with aging, influenced by sleep quality, chronic diseases, and reductions in blood flow to the brain. Pain, slower healing, and reduced resistance to infection become more common as immune and repair mechanisms are less robust.
This multi-system decline after 40 is a normal part of aging, but healthy lifestyle choices—especially exercise, strength training, and proper diet—can slow these changes and help preserve function and quality of life.
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