4 / Plan the day
Heat, cold and weather when your body is not typical
Public health sources name people with disabilities and chronic conditions among those at higher risk in heat, and describe cold risks. This page reports what they say.
Weather decides many outdoor plans, and for some bodies it carries extra weight. This page reports what the US Centers for Disease Control and Prevention (CDC) and the National Institute of Neurological Disorders and Stroke (NINDS) say about heat, cold, medications and long-term conditions. It is general information. Your own clinician knows how your condition and treatments interact with temperature, and the sources below repeatedly point you to them.
Who the CDC lists as higher risk in heat
The CDC's clinical overview of heat says that all people can be harmed by heat but that some may be more at risk. Its list includes people with disabilities, people with chronic health conditions, people with mental health conditions, adults over 65, and people who engage in strenuous outdoor activity. The CDC page on heat and chronic conditions explains that people with chronic medical conditions may be less likely to sense and respond to changes in temperature, and may be taking medications that make the effect of heat worse.
When a named condition affects heat tolerance
NINDS states that many people with multiple sclerosis (MS) find their symptoms are worse when they have a fever, are exposed to heat, or have had a common infection. That is the one condition-specific statement used here, because it is the one confirmed on an opened authoritative page. Other conditions may also be affected. The pages opened for this guide do not say so, so this guide does not either, and a clinician who knows your condition is the right person to ask.
Medications and temperature
The CDC's guidance for clinicians says medications and heat can interact, leading to potentially severe side effects, and that many medications, including over-the-counter ones, can impair heat tolerance and the body's ability to regulate its temperature. It notes the guidance reflects expert opinion. In its public heat page the CDC says many medicines can make you dehydrated or overheated on hot days, some need to be stored away from heat, and you should not stop or change medicines until you talk to your doctor. It also suggests a plan for refrigerated medications if heat causes a power outage.
Planning for hot days
The CDC's public heat page suggests staying in shade as much as possible, taking breaks, and doing outdoor activities during the coolest parts of the day or evening if possible. It recommends drinking plenty of fluids and carrying a water bottle, and says light yellow or clear urine usually means you are drinking enough. It lists symptoms of overheating: muscle cramping, unusually heavy sweating, shortness of breath, dizziness, headaches, weakness and nausea. It also points to the CDC HeatRisk dashboard, which gives a heat risk forecast by zip code, and suggests working with your doctor on a Heat Action Plan.
The CDC does not publish a temperature cutoff for outdoor activity on the pages used here. Setting your own limits, including how long to stay out, is a conversation for your care team. For the wider checklist of what to bring and who knows your route, see the trip-planning checklist, and for what to do if someone becomes ill outdoors, outdoor first aid basics.
Cold and winter weather
The CDC defines hypothermia as abnormally low body temperature and says that it and frostbite are dangerous conditions that can happen when a person is exposed to extremely cold temperatures. Its winter weather page says winter storms can bring cold temperatures, power failures and icy roads, which can make being outside dangerous, and that people should limit their time outside. It notes that staying indoors can help reduce the risk of car crashes and falls on ice. Ice and slippery ground bring balance concerns that balance and falls outdoors discusses. The pages opened for this guide do not break cold risk down by disability, so questions about how your own condition responds to cold are best taken to your clinician.
When you are choosing a destination, finding accessibility information for national parks covers where to look up facilities before you go.
The short version
The CDC lists people with disabilities and chronic conditions among those at higher risk in heat, and flags medications as a factor. NINDS confirms heat can worsen symptoms in MS. Beyond that, how weather affects an individual is a question for the clinician who knows their situation.