“It’s about to rain, I can feel it in my bones.” It is common thought that the Freddo and thehumidity can affect the musculoskeletal system, in particular the joints. In fact, most of the studies finds a increase of the perception of pain with the arrival of the cold, but in patients already affected from parologies such as rheumatoid arthritis or arthrosis. The relationship between weather forecast And painin fact, is of great interest to researchers, but it is difficult to carry out full-scale studies that take into consideration all the variables involved: from subjective perception from pain to lifestyle. The mechanism of action, however, is not at all clear, although various theories have been proposed.
Cold and humidity aggravate pre-existing joint problems
Even the 67% of the studies carried out found that during the winter increase the musculoskeletal pain. Don’t worry, if you are young and healthy you have nothing to fear. This correlation was highlighted only in elderly patients with pre-existing joint pathologiesin particular theosteoarthritis.
A curiosity: according to the analysis conducted by European Project on Osteoarthritis (EPOSA), it appears that Spanish and Italian study participants were more likely to report this sensitivity to weather conditions than Swedish participants.
Another aspect to consider, and which also emerges from this same project, is that the weather could influence thehumor and a bad mood could negatively alter the perception of pain.
The mechanism of action is still unclear
As regards the mechanism of action by which cold and humidity can act on the sensation of pain, we are still at sea and many mechanisms have been proposed, which probably act in synchrony. When it’s cold we move less and circulation in peripheral areas is slower: this leads to a stiffening of the joints (in fact in various studies, participants with more active lifestyles, despite their age, reported fewer painful episodes) which makes them less elastic.
It is also thought that the lowering of temperatures could increase the viscosity of synovial fluidthat liquid that permeates the bones engaged in the joint and makes them slide over each other without friction. In short, the “lubricant” of knees, ankles, wrists, hips and fingers!
Imagine yourself moving in waterfall or in mud: the more viscous the liquid, more difficult it becomes the movement, and it is the same for the joints.
It has also been proposed that climate Freddo And humid cause types of tissues with different densities (tendons, muscles and ligaments) to expand and contract differently, causing microtraumas and pain. Furthermore, drops in atmospheric pressure could affect the internal pressure of the joint, causing swelling and pain.
From animal studies we know that changes in pressure can modify the activity of neurons in the inner ear, increasing the perception of pain via the sympathetic system. And it is also hypothesized that in patients already suffering from joint pathologies, the pain fibers and receptors (nociceptors) are more sensitive to these variations in the external environment.
Finally, it is mandatory to mention inflammation, always faithfully accompanied byedema (accumulation of liquids). Joint pathologies are already characterized by a certain degree of inflammation and it has been found that low temperatures and humid environments can increase the presence of molecules typical ofinflammation. This creates a vicious circle which leads to an increase in edema: the more the edema grows, the more these liquids can impede the movement of the joints and cause stiffness and pain.
It is difficult to establish a cause-effect relationship
Many studies and even a meta-analysis (one of the best types of studies for synthesizing huge amounts of data in the literature) seem to be confirm that there is a correlation between the decrease in temperatures and the increase in joint pain. But this does not necessarily mean that the cold directly affects pain: in fact, a cause-effect relationship has not yet been proven.
These studies also have several imperfections (bias, in technical jargon). First of all, they are carried out through self-assessment of pain and since the perception of pain is a highly subjective parameterit is difficult to establish a standard.
Secondly, often they are not led blindly: patients know why they are asked to write down when they feel pain and they also know what theory is being tested (that cold and humidity increase joint pain). Even if we manage to hide the purpose of the study, it is certainly difficult to leave them in the dark about the weather: given that it is a very widespread popular belief, they could still be led to indicate an increase in pain, perhaps just because it is raining.
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