Does bad weather really increase joint pain?
Achy joint sufferers often swear they feel more pain when it is cold and rainy.
But new research conducted in association with University of Washington School of Medicine and Harvard University has discovered that twinges in hips and backs are just as likely when the weather is hot.
Using Internet searches for arthritis, knee and hip pain over five years in 45 cities, investigators discovered that within the study's focus span of 23 degrees to 86 degrees Fahrenheit (-5 to 30 degrees Celsius), knee pain searches peaked at 73 degrees (22 degrees Celsius) and were less frequent at higher temperatures, while hip pain searches peaked at 83 degrees (28 degrees Celsius) and then tailed off. They used searches for stomach pain information as a control.
"We were surprised by how consistent the results were throughout the range of temperatures in cities across the country," said lead author Scott Telfer.
Because knee and hip pain searches increased as temperatures rose until it grew uncomfortably hot, and rainy days tended to slightly reduce search volumes for hip and knee pain, the researchers inferred that "changes in physical activity levels" were primarily responsible for those searches.
"We haven't found any direct mechanism that links ambient temperature with pain. What we think is much more likely explanation is the fact that people are more active on nice days, so more prone to have overuse and acute injuries from that and to search online for relevant information. That's our hypothesis for what we'll explore next," Telfer said.
The stomach-pain searches functioned well as a control; those volumes were greater at low and high temperature extremes and ebbed in mild temperatures, a very different pattern from the knee and hip pain searches.
The full study has been published in PLOS ONE.