The idea that working out, particularly resistance training or weightlifting, will stunt growth or permanently make a person shorter is a persistent concern. This myth often causes hesitation, especially among adolescents, about starting strength programs. However, scientific consensus does not support the claim that properly performed exercise negatively impacts final adult height. Exercise does not prevent a person from reaching their maximum genetic height potential.
Exercise and Growth Plates
The central concern underlying the myth of stunted growth involves the epiphyseal plates, commonly known as growth plates. These areas of cartilage are located near the ends of long bones and are responsible for the longitudinal growth that increases stature during childhood and adolescence. They remain open and active until the end of puberty, at which point they fuse, and bone lengthening ceases.
The fear is that heavy weightlifting could cause a traumatic injury to these delicate structures, potentially leading to premature closure and reduced adult height. Research indicates that properly supervised resistance training does not increase the risk of growth plate injuries compared to other common youth sports. Injuries generally result from acute, uncontrolled trauma, not the controlled, progressive loading found in a well-designed strength program.
Far from causing harm, resistance and weight-bearing exercise stimulates bone remodeling, improving bone mineral density and overall bone strength. Studies show that adolescents who participate in structured strength training often exhibit higher bone density than their sedentary peers. The positive effects of controlled, age-appropriate resistance training on skeletal health are significant, provided that proper technique and supervision are consistently maintained.
Temporary Height Changes Due to Spinal Compression
Some people who measure their height immediately after an intense workout, especially one involving heavy axial loading like squats or overhead presses, may observe a minor reduction in stature. This phenomenon is a temporary and normal physiological response known as spinal shrinkage, and it is not a permanent height reduction. The effect is related to the intervertebral discs, the fluid-filled pads situated between the vertebrae of the spine.
These discs are composed largely of water and function as shock absorbers. When the spine is subjected to heavy vertical compression during a loaded workout, some fluid is temporarily squeezed out of the discs. This loss of fluid reduces the thickness of the discs by a few millimeters, resulting in a measurable, temporary decrease in overall height. This effect also occurs naturally, as a person is slightly shorter at the end of the day due to the cumulative effect of gravity.
The fluid loss from the intervertebral discs is completely transient and reverses itself with rest. When a person lies down and the spine is decompressed, the discs reabsorb the fluid, and the original height is fully restored, typically after sleep. This brief change in measurement is a normal mechanical consequence of spinal loading and has no long-term effect on maximum height potential.
The Primary Factors Determining Height
The overwhelming majority of a person’s final adult height is determined by factors entirely unrelated to exercise. Genetics is the primary determinant, with an estimated 80% of height variation being attributable to inherited DNA sequences. A polygenic inheritance pattern, involving thousands of gene variants, influences the blueprint for skeletal growth and development.
Beyond the genetic code, environmental factors play a significant role in realizing genetic potential. Adequate nutrition during childhood and adolescence is important, as the body requires sufficient protein, calcium, and vitamin D to build and lengthen bone tissue. Poor or inconsistent nutrition during these formative years can limit a person from reaching their genetically dictated height.
Hormonal regulation also serves as a powerful driver of linear growth. Hormones such as human growth hormone, produced by the pituitary gland, and thyroid hormones are essential for signaling the growth plates to produce new bone. Sex hormones, including estrogen and testosterone, are responsible for the adolescent growth spurt and ultimately signal the permanent fusion of the growth plates, marking the end of height gain. Exercise is beneficial for overall physical development, but it does not override these fundamental genetic, nutritional, or hormonal controls on maximum stature.