Weather sensitivity plays a hidden but crucial role when it comes to the debilitating symptoms of various disorders associated with SPD. Virtually all factors making up the weather can affect the physiological balance, and have the character of sensory stimuli for body’s sensory nervous system. The key factors are temperature, humidity and air pressure, of which each can lead to detrimental consequences for a patient’s well-being.

While the influence on external temperatures are obvious and already discussed in connection with the core body temperature, humidity and air pressure are less obvious in their influence, as both factors are barely noticeable under normal circumstances. Only in high altitudes or for instance in a steam sauna either of them has a direct influence on a person’s physiological state. Beyond that, healthy individuals don’t have problems when it comes to the physiological adaptation to changing weather.

When looking at possible ways how humidity or air pressure can affect the body and its sensory nervous system, one has to look at the possible “attack angles” on the body. These are the surface and all openings of the body, as well as all sensory nerve ends which are directly exposed to the outside. The result is an extensive list, which entails the skin, the ears, the mouth and the breathing apparatus. Each one of them is relevant for SPD patients when it comes to certain weather conditions.

How humidity influences the body

So far the medical literature appears to have only examined extensively the influence of high humidity on sweating, which can create problems for the body to regulate its core temperature. While this indeed may be a the case, for SPD patients, this may be only a minor factor when it comes to humidity. Much more important appears to be the nose and sinus, which are responsible to bring the outside temperature to optimal humidity and temperature before it is taken in by the lungs.

Optimal humidity and temperature of the air are essential for breathing. The wrong humidity can lead to a suboptimal diffusion of oxygen as well as an ill health with infections, whereas the wrong temperature can lead to a direct cooling or heating of the body’s core. The consequences of all three problems can be observed in SPD patients. Suboptimal diffusion of oxygen leads to fatigue; especially CFS/ME patients often suffer of infections; and it is well established that a dropping core body temperature leads to drowsiness.

The possible relevance of humidity as symptom trigger can be explained by the presented theory for SPD. While the adaptation in healthy individuals works automatically, the signal noise prevents the sensory information from getting to the relevant organs which are responsible for the nasal adaptation. In this perspective, the possible relevance of humidity as symptom trigger is especially relevant for air of high absolute humidity as it contains many water droplets. This is confirmed by at least one patient, who’s well-being increases in room-tempered atmospheres of less than 55% humidity.

• A solution for at home would be an electric room dehumidifier, maybe together with a combination of humidifier & purifier to both stabilize the humidity at a specific level and to reduce the number of bacteria in the air. During the day, staying in a building with a strong air conditioning can be recommended. The most optimal conditions are prevalent in libraries, which need both a stable temperature and low humidity for their books.

How air pressure influences the body

The relevance of air pressure for breathing can be observed in the lungs. With every breath, they built up their own internal air pressure. The amount of air pressure is adapted to the amount of oxygen needed by the body. In physiologically demanding situations the breathing intensifies to provide the muscles of the body with the increased demand for oxygen. Besides the internal adaptation, the breathing intensity must also be adapted to the outside air pressure, because different levels of air pressure mean different amounts of oxygen available for the breathing process.

In healthy patients, this adaptation process is happening automatically, as it is the case with the adaptation to humidity. Only extreme situations lead to maladaptation, as it is the case for instance in high altitudes. If air pressure is too low to cover the body’s need for oxygen, hormones like adrenaline and epo are emitted to temporarily support the low oxygen environment. If the air pressure drops too low, fatigue sets in and finally suffocation with first confusion and in the extreme case death.

Patients suffering of SPD, these breathing problems, which usually only occur in high altitude and is known as mountain or altitude sickness, can also occur under normal circumstances. The signal noise in the sensory nervous system prevents information on changing air pressure from reaching the relevant organs responsible for the adaptation of the breathing. This means that as soon as air pressure starts dropping or falls below a certain threshold, SPD patients start suffering of altitude sickness, just as a mountaineer on 6000m elevation does. They helplessly go into dysfunction until the air pressure stabilizes again on a sustainable level.

• The number of remedies against dropping air pressure are limited, unfortunately. One possible solution could be in using an oxygen concentrator to increase the inflow of oxygen during critical air pressure drops. Beyond that, there is only the solution of spending the critical phases in air-tight rooms, or to relocate to a place on sea level, which ideally has only little changes in air pressure. The number of regions worldwide offering those conditions is rather limited, though.

Dizziness, migraines and the ear

Some SPD patients suffer of episodes with dizziness and migraines. While many are able to find a connection between the two, few are able to trace these episodes back to their root cause. As it turns out, the ear can be responsible for this specific problem in patients, who’s signal noise is expressed as increased sensitivity. The reason behind this is because the ear is the body’s gyroscope, which is needed to keep the body ubright. But the ear is also connected to the outside, which means that air pressure changes are affecting the ear’s physiological state.

Among healthy individuals, problems in this regard tend to only occur in extreme situations with very rapidly changing air pressure, as it is the case during airplane take-offs or landings. Given the signal noise and increased sensory sensitivity SPD patients suffer of, even small changes in air pressure can lead to symptoms healthy individuals only experience in extreme situations. These symptoms can include a feeling of pressure in the head, dizziness, migraines or other symptoms in connection neurological processes.

• A viable solution for the dizziness problem in connection with changing air pressure are airplane ear plugs, which are designed to keep the air pressure stable during the critical flight phases. WeatherX has even specialized on this phenomenon as general health problem and offers a warning app to their earplugs designed to inform you when air pressure is about to start dropping in your location.