New research seems to somehow support the old aphorism that changes over time affect pain by proving, in some standard quantitative sensory tests, that weather-related factors do affect pain tolerance. magazine ‘PAIN’, the official publication of the International Association for the Study of Pain (IASP).
“Although they are observational, these results suggest that time has a causal, non-linear and dynamic effect on pain tolerance,” according to the new research, led by Erlend Hoftun Farbu, a doctoral student at the Arctic University of Norway (UiT). . But it is not yet clear whether the relationship between weather and pain involves physiological or psychological factors, or a combination of factors.
The study included participants in the Tromso Study, an ongoing study of the health of the inhabitants of that city in northern Norway, located north of the Arctic Circle. Some 19,500 participants, with a mean age of 57 years, were evaluated in two quantitative sensory tests, widely used in research studies. The pressure pain tolerance test (PDT) measured the subjects’ ability to tolerate pain produced by increasing pressure applied to the lower leg. LThe Cold Pain Tolerance Test (TDF) measured how long they could tolerate immersion of the hand in cold water.
The results of pain tolerance tests were analyzed in relation to data on meteorological conditions: temperature, barometric pressure, rainfall, relative humidity and wind speed. Associations between pain tolerance and meteorological factors, as well as seasonal or short-term variations, were evaluated.
In general, the TDP results did not show significant seasonal variations and were not strongly related to meteorological variables when the entire study period was considered. However, the correlations varied depending on the time period studied. The data suggested a “short-term non-random variation” in the results of the TDP: the time frame of the short-term variations of the TDP reflected the time frame of time. In addition, temperature and barometric pressure predicted future TDP values.
In contrast, TDF results showed clear seasonal variation: subjects were able to tolerate cold-induced pain longer in colder times of the year. Tolerance to cold pain also varied according to meteorological variables. “This fits perfectly with research on cold adaptation,” says Farbu. As you get used to the cold, you may be able to tolerate more cold. “
And add that “Temperature and barometric pressure appear to be more strongly related to PTO and TDP, and predict future TDP. However, the effect of temperature is probably influenced by humidity and wind, as they could alter heat loss ”.
Many people, especially those with chronic pain, believe that weather or weather-related factors can cause or aggravate pain episodes. While some studies have supported associations between weather and pain, others have reached conflicting results.
“If we are correct that the relationship is dynamic and not linear, it could perfectly explain why many studies find small effects and conflicting results,” says Farbu. If an effect is changing over time and you average it over time, you may end up with no effect. “
The findings, especially for CPT, “should be taken into account when planning future studies on pain tolerance,” the researchers write. They look at some of the ways that time might affect pain tolerance. One possible explanation is “core mechanisms,” in which time-related variables affect parts of the brain involved in pain processing. Another possibility is that the weather affects people’s mental state – as in seasonal depression, for example – which could affect their ability to bear pain.
“In summary, it is unlikely that a single mechanism can explain the observed variations in pain tolerance,” the authors conclude. It is more likely that it is the net result of many mechanisms, possibly antagonistic ”.
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