Astronauts Experience Acute and Chronic Pain During and After Spaceflight

During and after spaceflight, astronauts experience lower back pain (LBP), lumbar muscle hypertrophy, reduced range of motion, and significant disc herniations and dehydration, according to study results published in the Journal of Pain Research.

Spaceflight can cause physiologic changes in the spine, contributing to the onset of acute and chronic pain. These missions reduce the spine’s range of motion, with astronauts often losing muscle in the lower back, especially the lumbar spine. Owing to the lack of comprehensive literature in this topic area, researchers conducted a systematic review and meta-analysis to determine the effects of spaceflight on the spine and to assess the frequency of LBP in astronauts.

The researchers analyzed the risk of bias and quality of the studies and categorized the level of evidence via the GRADE system. Spinal pathologies were evaluated via ultrasonography and magnetic resonance imaging. Random-effects models were used for statistical analysis.

The review included a total 93 astronauts who participated in randomized controlled trials and longitudinal studies that were published between 2014 and 2023. Sample sizes ranged from 6 to 20 astronauts, the mean participant age ranged from 38 to 55 years, and the duration of spaceflight ranged from 14 days to 6 months.

Most astronauts (77%) reported pain during spaceflight, with 70% to 85% developing LBP. The most common pain regions were the iliac crest at the posterior iliac spines on both sides, the broad central lower lumbar region, the small area at the height of the iliac crest, and at L5.

After spaceflight, 47% and 33% of astronauts reported acute and chronic pain, respectively. They also experienced moderate to severe muscle hypertrophy in the lumbar multifidus, particularly in the L4-L5 and L5-S1 segments. In regard to other spinal changes, spaceflight was associated with moderately decreased range of motion as well as significant disc dehydration and herniations.

Study limitations include small sample sizes, potential selection bias, and the lack of standardized assessment protocols.

According to the researchers, “Our findings show that space travel can lead to serious spinal issues and a high risk of pain.” They added, “These results highlight the need for better health strategies to protect astronauts during and after their missions.”

This article originally appeared on Clinical Pain Advisor