Premature birth is defined as birth occurring before 37 gestational weeks [1]. Although the prevalence of preterm mortality was once very high, major strides in neonatal intensive care have substantially increased the survival rate [1]. Unfortunately, even if birth is successful, being born during the preterm period may significantly impair a person’s physical activity and strength, both during their childhood and for the rest of their life [1].
To begin with, several studies have noted the lowered tendency of preterm children to engage in physical activity. To investigate this topic, FitzGerald and colleagues compared 123 children born less than 30 weeks into gestation with 128 children born at term [2]. They found that the preterm children tended to have lower physical activity levels than term-born children [2]. Furthermore, studies have found that adults who had been born weighing less than 1500 grams (3.3 pounds) engaged in significantly less leisure time physical activity than people who were born at a healthy weight [1].
While some studies have reported similar results, other experiments suggest that not all preterm children engage in less physical activity than children born at term [3, 4]. For one, a UK study of children aged 5, 7, and 11 found that prematurity was associated with a minimal, if any, reduction in physical activity levels [5]. Although it may be unclear whether certain preterm children exhibit differences in physical activity compared to their at-term peers, children who suffer from cerebral palsy (CP) or developmental coordination disorder (DCD), which are more common among preterm children, have poorer physical activity participation [4]. Accordingly, while physical activity may offer children improvements in motor ability, children with CP and DCD may not be able to reap these gains easily.
Just as physical activity can be affected by preterm birth, strength can also be detrimentally impacted. The aforementioned study conducted by FitzGerald et al. demonstrated this association: children born preterm generally demonstrated poorer muscle strength than children born at term [2]. Unfortunately, this lower strength may continue to impact children into adolescence. For example, Rogers and colleagues identified how extremely low birth weight teenagers tended to have less leg power, abdominal strength, and grip strength [3].
Confronted with these challenges, the importance of physical activity for preterm children cannot be understated. Inactivity is strongly linked to conditions such as cardiovascular disease, obesity, and metabolic syndrome [1]. Ensuring that preterm children receive early exercise is important for encouraging activity later on in life [1]. A study led by Tosun and colleagues found that having children as young as infants participate in a daily physical activity program promoted increased tibial speed of sound (SOS) and mid-upper arm circumference [6]. As bone strength and density increase, so does tibial speed of sound; mid-upper arm circumference is also an indicator of strength [7]. Together, these results reaffirm the absolute importance of exposing preterm children to physical activity early in life.
Along with physical activity, preterm children would benefit from pronounced surveillance from their parents, as well as more attentive clinical care [2]. While children born extremely early may have a diminished possibility of improvement, many other preterm children have a high chance of leading healthy lives.
References
[1] M. Nordvall-Lassen et al., “Leisure time physical activity in 9- to 11-year-old children born moderately preterm: a cohort study,” BMC Pediatrics, vol. 18, no. 163 p. 1-8, May 2018. [Online]. Available: https://doi.org/10.1186/s12887-018-1141-8.
[2] T. L. FitzGerald et al., “Strength, Motor Skills, and Physical Activity in Preschool-Aged Children Born Either at Less Than 30 Weeks of Gestation or at Term,” Physical Therapy, vol. 101, no. 5, p. 410-417, May 2021. [Online]. Available: https://doi.org/10.1093/ptj/pzab037.
[3] M. Rogers et al., “Aerobic Capacity, Strength, Flexibility, and Activity Level in Unimpaired Extremely Low Birth Weight (≤800 g) Survivors at 17 Years of Age Compared With Term-Born Control Subjects,” Pediatrics, vol. 116, no. 1, p. e58-e65, July 2005. [Online]. Available: https://doi.org/10.1542/peds.2004-1603.
[4] K. L. Cameron et al., “Motor outcomes of children born extremely preterm; from early childhood to adolescence,” Seminars in Perinatology, vol. 45, no. 8, p. 1-6, December 2021. [Online]. Available: https://doi.org/10.1016/j.semperi.2021.151481.
[5] J. Spiegler, M. Mendonca, and D. Wolke, “Prospective Study of Physical Activity of Preterm Born Children from Age 5 to 14 Years,” The Journal of Pediatrics, vol. 208, p. 66-73.e7, May 2019. [Online]. Available: https://doi.org/10.1016/j.jpeds.2018.12.013.
[6] O. Tosun et al., “Daily physical activity in low-risk pre-term infants: Positive impact on bone strength and mid-upper arm circumference,” Annals of Human Biology, vol. 38, no. 5, p. 635-639, October 2010. [Online]. Available: https://doi.org/10.3109/03014460.2011.598187.
[7] Z. Korčeková et al., “Tibial speed of sound changes in preterm infants during the first year of life,” Bone, vol. 132, p. 1-4, March 2020. [Online]. Available: https://doi.org/10.1016/j.bone.2019.115191.