When you’re exposed to heat, does it feel like you’re burning up? Does it seem impossible for you to cool off? Or maybe it’s cold that bothers you, chilling you to the bone, leaving you unable to warm up.
Or are you one of those people with fibromyalgia (FMS) and chronic fatigue syndrome (ME/CFS) who is cold all the time, or hot all the time, or alternately hot or cold while out of sync with the environment?
If any of those scenarios sound familiar to you, you may have a symptom called temperature sensitivity.
We don’t yet know exactly what causes this symptom, but we do have some compelling research. Much of it suggests abnormalities in the autonomic nervous system, which deals with homeostasis (your body’s ability to keep temperature and other factors within normal ranges) and our bodies’ reactions to different situations, including the “fight or flight” reaction.
With that established, researchers are now able to look deeper into that system to figure out what exactly is going wrong, and they’re finding some interesting things.
Temperature Sensitivity in Fibromyalgia
In FMS, some research shows abnormal body temperatures, an inability to adapt to changes in temperature, and a lower pain threshold to both heat and cold stimuli—meaning that it takes less extreme temperatures to make you feel pain. For example, sunlight shining through a car window onto your arm may cause burning pain in you but only mild discomfort in someone else.
A ground-breaking study published in Pain Medicine suggests a reason for our temperature sensitivity, and it’s one based on a series of discoveries.
The first step involved people who may be the exact opposite of fibromites—those who can’t feel pain at all. It’s a rare condition that they’re born with. Doctors observed that these people can feel temperature, which was confusing. Why would the same nerves that could feel one type of stimuli (temperature) not be able to feel another (pain)?
That question led them to a discovery: They’re not the same nerves at all. In fact, we have an entirely separate system of nerves that sense temperature. These nerves are on our blood vessels, and scientists used to think they just dealt with blood flow.
So, it turns out that these special nerves don’t just adjust blood flow, they detect temperature. They then became a logical target for FMS research, since we’re known to have both blood flow abnormalities and temperature sensitivity.
Sure enough, researchers found that FMS participants in their study had extra temperature-sensing nerves along special skin blood vessels called AV shunts. They’re in your hands, feet, and face. Their job is to adjust blood flow in response to temperature changes. You know how when it’s really cold out, your cheeks get rosy and your fingers get all puffy and red? That’s because the AV shunts are letting in more blood, trying to keep your extremities warm.
This is the first study looking at how this system is involved in our illness, so we can’t say for sure whether it’s accurate. However, it is an interesting direction for more research and an explanation that appears to make a lot of sense.
Temperature Sensitivity in Chronic Fatigue Syndrome
We don’t have a lot of research on this symptom in ME/CFS so far, but we have learned a little about it.
An interesting study involved identical twins. In each set of twins, one sibling had ME/CFS and the other did not. Researchers found that the ones with ME/CFS did have different responses to cold than their healthy siblings when it came to both pain tolerance (how much pain they could handle) and pain threshold (the point at which the cold became painful.)
A study published in Pain revealed something about a process called pain inhibition. In a healthy person, the brain takes steps to lessen the pain that’s anticipated (like when a nurse gives you a shot) or pain that’s repeated (like walking on a pebble in your shoe.)
In ME/CFS, though, researchers found that the inhibition process was slower to respond to cold stimulation. They believe this could play a role in the chronic, widespread pain in this disease but point out that more research is needed to confirm this.
A study looking at adolescents with ME/CFS may have uncovered some important information about homeostasis. Researchers found that when a hand was exposed to cold, the kids with ME/CFS had significantly more shivering and sudden changes in skin color than their healthy counterparts. Blood flow to the hand also reacted differently in the control group and illness group. Body temperatures dropped more among the ME/CFS participants, as well.
So, this symptom is established in the medical literature and we have some early findings that more research can be based upon.
A Word From Verywell
Also, talk to your doctor about this symptom. It may help him/her draw conclusions about what’s going on in your body and what might help you feel better.