As the seasons change, you may notice your Parkinson’s disease symptoms getting worse. You may be more sensitive to temperature, experience more fatigue, and movement may become slower. Though it’s not often talked about, extreme changes in weather can exacerbate symptoms.
Many patients with Parkinson’s disease report greater stiffness and pain during the winter months, along with more freezing and slowness. Others report that shivering from the cold makes their tremors worse. Falls related to Parkinson’s also often occur more often during freezing episodes.
Some patients may also experience worsened symptoms during the summer months. Heat and humidity can make it hard for the body to function properly. Some patients report feeling “drained” or exhausted during the summer.
The four main symptoms of Parkinson’s disease are tremor, rigidity, bradykinesia, and postural instability. But there are non-motor symptoms as well, such as fatigue, excessive daytime sleepiness, and cognitive changes.
How Does Weather Affect Parkinson’s Disease Symptoms?
Weather changes are difficult for many people, but they can be even more challenging for people with Parkinson’s. Since Parkinson’s affects the nervous system, which controls body temperature, patients can be more sensitive to heat and cold. In the winter, Parkinson’s patients may have a harder time feeling and staying warm. In the summer, extreme heat can make it difficult for the muscles to work properly.
Research has found that the classic symptoms of Parkinson’s disease can be brought on through hypothermia. Accidental hypothermia, an unintentional drop in core body temperature to less than 95° F (35° C), is often serious in neurodegenerative diseases. There have been cases of accidental hypothermia in Parkinson’s patients, most of which occur during the winter and can occur despite a well-heated house.
There has not been a lot of clear evidence to support seasonal fluctuations of Parkinson’s disease symptoms, and only a handful of studies have examined the possibility of circannual or yearly fluctuations. One study of 546 Parkinson’s disease patients did not find any differences in Unified Parkinson’s Disease Rating Scale (UPDRS) scores over the four seasons of the year. The UPDRS monitors the response to medications used to reduce the signs and symptoms of Parkinson’s disease.
The first comprehensive study showing seasonal differences in non-motor symptoms in Parkinson’s patients found that the non-motor symptoms of Parkinson’s disease fluctuate throughout the year. The study divided 372 patients who were taking part in a non-motor longitudinal study into three groups based on their date of assessment using a simplified seasonal model: November-February, March-June 15, and June 16-October. The primary outcome of the study was a seasonal difference in non-motor symptoms scale total scores, with higher scores reflecting greater disability.
The researchers used the following non-motor symptom scale (NMSS) domains:
- Cardiovascular and falls (domain 1)
- Sleep/fatigue (domain 2)
- Mood/cognition (domain 3)
- Perceptual problems/hallucinations (domain 4)
- Attention/memory (domain 5)
- Gastrointestinal tract (domain 6)
- Urinary (domain 7)
- Sexual function (domain 8)
- Miscellaneous (pain, smell, weight loss, and sweating; domain 9)
The three groups were identical as far as disease onset and duration, as well as their stage on the Hoehn Yahr scale. They were also identical as far as gender and Levodopa equivalent dose. Levodopa (L-dopa) is a common medication used to treat the motor symptoms associated with Parkinson’s disease.
The study showed seasonal differences in NMSS total scores. Researchers observed that the winter months had the highest scores (more complaints) and the summer months had the lowest scores, demonstrating that non-motor symptoms were more severe during winter compared to summer. NMSS total scores were 57.1, 50.7, and 45.1 for winter, spring, and summer.
They observed differences in cardiovascular symptoms (domain 1), perceptual problems (domain 4), and miscellaneous symptoms (domain 9). The winter group reported higher scores for cardiovascular and miscellaneous symptoms compared to the summer group, while the summer group reported higher scores for perceptual problems.
There was also a trend observed for sleep and fatigue (domain 2). The NMSS scores for sleep and fatigue were higher in the winter than in the summer. The researchers observed that smell was better in the summer months than in the winter and spring months.
The researchers did not observe a change in depression scores across the different seasons. This may have been related to the use of the Hospital Anxiety and Depression Scale (HADS), which is used as a screening tool for depression and not a diagnostic tool. In Parkinson’s, the HADS is not recommended for scoring the severity of depressive symptoms. The researchers also noted that while depression is known to fluctuate in severity across seasons, depressed patients may be inclined to answer more negatively to all questions.
The fact that symptoms became worse in the winter months and were less pronounced in the summer months suggests a dysfunction of the suprachiasmatic nuclei (SCN), which is the body’s natural clock. The SCN is located in the hypothalamus and is the central pacemaker of the circadian timing system. It regulates most circadian rhythms in the body.
Researchers concluded that the changes in non-motor symptoms might be explained by altered circannual regulation in Parkinson’s disease. They recommended that seasonal variations in Parkinson’s symptoms be managed by daily care regimens, such as medication. However, the researchers noted that the study did not follow the same patients during the winter and summer months,
The severity of Parkinson’s disease symptoms don’t just fluctuate with the seasons. They can fluctuate throughout the day too, particularly motor symptoms. Responsiveness to levodopa treatment can also decrease throughout the day.
How do seasons affect Parkinson’s disease prescriptions?
Not only do seasons affect the symptoms of Parkinson’s disease, but they also affect medications prescribed to treat Parkinson’s.
One study examined three elements of the weather and the impact on Parkinson’s disease symptoms and medications: temperature, ultraviolet light, and relative humidity. The researchers believed that weather might cause Parkinson’s patients to present with increased symptoms, leading to seasonal adjustments in levodopa equivalent dose (LED).
Researchers sourced data from the Pharmaceutical Benefits Scheme and Bureau of Meteorology in Australia using 23 years of monthly time. They found that the prescribed LED was 7.4% greater in January (summer) and 8% lower in July (winter). Statistical analysis of linear and non-linear models showed that temperature was associated with prescription of Parkinson’s medications; for every 1% increase in temperature, there was a 0.18% and 0.13% increase in LED dose respectively.
Although temperature and ultraviolet light are highly correlated, neither model reported a statistically significant relationship between ultraviolet light and LED. However, scientific literature suggests that changes in ultraviolet light will have a delayed effect on Parkinson’s disease because UV light is reported to affect Parkinson’s through its synthesis of vitamin D.
Does season of birth affect Parkinson’s disease risk?
Several studies have sought to find a relationship between the season of birth and the risk of developing Parkinson’s disease later in life. Small-scale studies have suggested that there is a slight excess of Parkinson’s risk in people born from January to March. Another study suggested an increased risk of Parkinsonism, not necessarily Parkinson’s disease, in people born in winter and early spring. Parkinsonism is a general term referring to a group of neurological problems similar to those seen in Parkinson’s. Other studies have suggested that people born during flu pandemics also have a higher risk of developing Parkinson’s.
A 2007 study of 8,168 Parkinson’s patients across Canada examined and compared patterns of the seasonality of birth with the general Canadian population. The researchers also compared the number of patients born during major flu pandemics with the number of patients born in the surrounding years. The study did not find any evidence of systematic seasonal variation in Parkinson’s disease risk by birthdate or by clustering of birthdates during flu pandemics.
A 2010 study using data from the Nurses’ Health Study (NHS) and Health Professional Follow-up Study (HPFS) examined whether early life factors, including season of birth, affected Parkinson’s disease risk. Other factors that were examined were parental age at birth, birth weight, having been breastfed, handedness, preterm birth, and multiple births. The NHS followed 121,701 female nurses from 1976 to 2002, and the HPFS followed 51,529 male health professionals from 1986 to 2002.
Researchers found a modest association for the season of birth in NHS patients; women born during the summer months (June to August) had an 82% higher risk of Parkinson’s than women born during the winter (December to February). In a pooled analysis of both NHS and HPFS patients, there was a 30% higher risk of Parkinson’s associated with spring birth vs. winter birth.
There are other factors and environmental exposures, such as vitamin use or intrauterine viral exposure to flu, that may account for inconsistencies in the results of studies around the season of birth and Parkinson’s disease risk.
How to cope with seasonal changes
If your Parkinson’s disease symptoms get worse with the change of seasons, there are a couple of different ways you can cope.
In the winter, try to stay as warm as possible. This might mean dressing in layers or using thermal underwear. You may want to use an electric blanket or reusable hot pack, just be careful not to burn yourself. Try to avoid going outside unless you absolutely need to. If you need groceries, you may be able to get them delivered, or you can ask a friend or family member to pick them up for you. If you’re running low on medication, see if your pharmacy offers home delivery and if they can give you a 90-day supply that will last you through the winter.
In the summer, you can manage your Parkinson’s symptoms by staying hydrated. You should also try to avoid any strenuous activity when it’s very hot outside. If you can, stay indoors between 11 am and 3 pm when the sun is at its hottest. If you do have to go out, try to stay in the shade to keep cool. You can also stay cool by wearing loose cotton clothing.
Managing your Parkinson’s disease can be challenging any time of the year, but extreme temperatures can make your symptoms much worse. At PatientsLikeMe, there are over 30,000 Parkinson’s patients who know what you’re going through. Join the conversation to connect with others who are like you and can support you through your illness.