How Geography, high altitude and cold weather can play a role

Through APDA’s Ask the Doctor portal, we receive many questions on a vast array of topics. (Feel free to submit your own question at any time.) Many readers have noted that geographic or seasonal factors seem to impact their Parkinson’s disease (PD) symptoms and are curious if others have experienced the same thing.

Let’s take a closer look at how factors such as weather, geography, and altitude could have a potential impact on PD symptoms.

Seasonal effects on Parkinson’s: cold weather and shortened days

Winter, spring, summer, fall – can the season or weather really make a difference when it comes to your PD symptoms?  It seems intuitive that very hot or very cold weather can impact a person’s PD symptoms, potentially worsening pain or stiffness. When thinking about how the season or weather might impact PD symptoms, a number of potential factors come to mind. All of these issues could contribute to variability of PD symptoms.

Sensitivity to temperature

In people with PD, there can be pathologic changes in the parts of the brain that regulate temperature, as well as in the nerves that regulate the sweat glands. This means that people with PD may be more impacted by both hot and cold temperature. People with PD may experience increased or decreased sweating, or a combination of both.  Another temperature regulation symptom that some people with PD experience is the sensation of cold hands or feet. Because of this difficulty in regulating temperature. people with PD may report that their symptoms are worse, with increased stiffness and slowness, in both very hot and very cold weather.

Ability to exercise

Exercise is essential for people with PD and can help mitigate symptoms, but it can be harder to reach your exercise goals in the very hot or very cold weather.

How exercise is impacted by the weather:

• Walking outside and some other exercise opportunities (i.e., swimming, tennis) are easier in the warmer months.
• Many people with PD are generally more homebound in the very hot and very cold weather with decreased overall activity levels.
• A reduction in movement and exercise can definitely increase PD symptoms.

What to do: If the very hot or very cold weather is keeping you from your usual exercise, it is essential to find ways to keep moving indoors. There are many online fitness classes specifically designed for people with PD that you can join from anywhere.

Waking hours of light/dark

Depression can be more pronounced in the winter months.

This is impacted by:

• An increased number of hours in the dark.
• Sleep quality may vary depending on the season because of the level of comfort with the ambient temperature and number of hours spent in the darkness.
• Increased number of hours spent in the dark can impact hallucinations. 

What to do: If the shorter days and lack of daylight are affecting your mood or sleep, talk with your doctor. You may be able to counteract the negative effects with light therapy, talk therapy, and possibly with antidepressant medications.

Diet

With more fresh fruits and vegetables available in the summer months, your diet may be altered depending on season.  Heavier meals are more common in cold weather months, which can lead to lethargy, weight gain, and more.

What to do: Be mindful of eating a balanced diet all year round. Look for healthy, nutrient-rich foods. The MIND and Mediterranean diets have shown benefits for people with PD. Consult a nutritionist if you’re having trouble, and you should discuss any dietary changes that you make with your neurologist.

Intercurrent Illness

Intercurrent infections (i.e., flu, colds, etc.) are more common during the cold weather of the winter months, which can worsen PD symptoms. In fact, it is a very common scenario that a sudden worsening of PD symptoms can be triggered or exacerbated by the presence of an infection.

What to do:

• Proper nutrition, adequate sleep, and exercise can help you stay healthy during cold-weather months.
• Be sure to reduce your risk of infections by frequently washing your hands.
• Avoiding in-person contact with people who are sick as well as crowded areas.
• Get timely flu and COVID-19 vaccinations as recommended by medical professionals.

Is there scientific proof that the time of year can affect PD symptoms?

Despite these potential reasons that PD symptoms might be more pronounced at different times of year, especially in the winter, with cold weather and shortened days, studies that have been conducted to directly study this issue have had mixed results.

In one initial study, patients’ motor scores, as defined by the Unified Parkinson’s Disease Rating Scale, were compared in various months of the year, and no differences were found. Similarly, another study demonstrated that seasonal variation did not affect hallucinations in PD, with no exacerbation of the condition during the winter.

In a different study, however, prescriptions of PD medications were analyzed in the winter and summer months. More PD meds were prescribed in the winter months, suggesting that there is a variability in PD symptoms depending on the season. Another study looked at non-motor symptoms which suggested that patients’ blood pressure fluctuations, sleep, and hallucinations were worse in the winter months than in the summer.

Although results from research studies are not clear, it is certainly possible that some people with PD may experience a variability in their symptoms as it relates to the season. If this is the case for you, discuss this with your doctor. Adjustments in your treatment and lifestyle depending on the time of year may be a good solution to help you feel better year-round.

Geography and its effect on Parkinson’s

Some people wonder if where they live influences their PD symptoms. Whereas other neurological diseases such as Multiple sclerosis demonstrate a clear North-South gradient, with more cases diagnosed in cooler climates, the same trends are not seen in PD.

This study analyzed the varying rates of PD based on geography (APDA helped to fund this study!) and demonstrated a concentration of PD in the Midwest and Northeast. However, these higher diagnosis rates do not align with differences in climate but rather may be attributable to environmental exposures, such as pesticides and industrial toxins. You can read more and hear more about Parkinson’s disease and environmental exposures. At least within the US, there is no data to suggest that once PD has been diagnosed, symptoms are variable depending on where a person lives.

High altitude and its effect on Parkinson’s

Another factor that our readers have asked about is the effect of altitude on PD symptoms.

Whether you have PD or not, if you travel to a location with high elevation without giving your body a chance to get accustomed to the new elevation you may experience altitude sickness. Note: Altitude sickness is more likely to occur when reaching 8,000 feet or above. For context, Denver is at 5,000 feet and many mountains in the Rockies can be 8,000 feet or higher.

Altitude sickness occurs because as elevations increase, oxygen levels and air pressure are lower, which can cause symptoms of headache, nausea, and fatigue. Typically, symptoms are mild and resolve as your body adjusts to the elevation. Some people, however, can develop moderate or even severe symptoms which may include trouble breathing. Some other difficulties are neurologic symptoms such as trouble walking and confusion. When severe symptoms occur, the person must be taken to a lower altitude immediately and hospitalization may be required.

In rare cases, the neurologic symptoms of severe altitude sickness can include parkinsonism, or the slowness, stiffness and walking/balance difficulties that characterize Parkinson’s disease. In cases where this occurs, the symptoms typically reverse with recovery from altitude sickness.

There is a lot of variability in how people with PD react to changes in altitude. Although many people with PD will not notice a major difference in symptoms when they arrive at a high elevation, many others will report that the first few days at a high altitude is a difficult adjustment, and their PD symptoms are temporarily worse.

Despite these concerns for altitude sickness, there are many anecdotal reports that claim that once the body is acclimated to the higher altitude, PD symptoms are actually reduced. As of now, there are no epidemiologic studies in the medical literature that characterize the effects of altitude on PD symptoms, or even studies that investigate PD prevalence and symptomatology in areas of the world at varying altitudes, so we only have individual people’s personal experiences to go on. More research is clearly necessary.

Researchers have tried to explain why high altitude may have a beneficial effect on the brain. One theory explains that although acute and drastic low oxygen levels are harmful to the brain, more chronic and less severe decreases in oxygenation can be neuroprotective. More research needs to be done to bolster this theory.

PD symptoms can be variable within one day and from day to day for a whole host of reasons, including sleep, diet, and level of anxiety. It is not surprising that factors like weather and altitude also may influence PD symptoms – and that these effects are variable among people with PD. As always, be sure to talk to your doctor about any new symptoms you are experiencing as there may be ways to help you feel better.

Tips and Takeaways

• PD symptoms can vary depending on season, with both hot and cold weather having an impact.
• Geography can influence risk of developing PD, but not PD symptoms once it is diagnosed.
• Acute changes in altitude can negatively affect PD symptoms for some, although once acclimated to the higher elevation, symptoms should return to normal.
• Some people with PD report that their symptoms are actually better at higher altitudes.