People with MS can be sensitive to extremes of temperature, and find that heat or cold makes their MS symptoms worsen.
Some people can find they experience problems with both extremes of temperature. This can be hard to explain to people around you, as different symptoms may be affected by heat and cold. You may find you need to monitor the temperature and situation around you and take steps to keep yourself at a comfortable temperature.
What causes temperature sensitivity in MS?
Temperature sensitivity could be caused a number of ways. Extremes of heat and cold may affect the speed at which nerve impulses can travel along your nerves, particularly where there has been demyelination or nerve damage. Alternatively, MS may have caused a lesion in the part of the brain that controls or responds to body temperature. Your brain may not trigger sweating or shivering responses that keep your body at the best temperature for comfort.
Although unpleasant, the effects of heat and cold are temporary and do not cause any permanent damage to nerves. The symptoms are generally quickly reversed when body temperature returns to normal. If they do not, then discuss it with your doctor or MS team.
Between 60% and 80% of people with MS find that heat can cause their symptoms to worsen. This might involve a build up of fatigue, blurred vision, loss of balance or a worsening of cognitive symptoms such as concentration or memory. The effect of temperature changes on your visual symptoms is known as Uhthoff's phenomenon.
Summer weather, excessive central heating, vigorous exercise or having a fever can all raise your core body temperature. You might also find environments with lots of people crowded together uncomfortable. If you have MS, just a small rise in core body temperature can make a difference to how you might feel.
Being heat sensitive may affect the activities you choose to do. If you are sensitive to heat, you could opt for resistance exercise rather than endurance exercise, as this tends not to raise the core temperature so much.
Dealing with the heat
- Have regular cold drinks or suck an ice cube or frozen pineapple chunks.
- Spray your face and wrists with a plant mister filled with iced tap water
- There are also commercially available sprays available from high street pharmacists that will stay cool throughout the day.
- Some people find eating makes them warmer, and so it may be an idea to choose salads and sip iced water while eating. A cooling dessert can help.
- When you take a bath or shower, start with tepid water and reduce the heat gradually.
- A floor or desk fan can help to keep the temperature down and the air flowing in a room. A hand held fan can be useful when moving around.
There are many different options for cooling hats, scarves, ties and wrist bands that can be worn during day to day activities and are relatively inexpensive. These contain a gel or other substance that can be pre-cooled before wearing, usually by soaking in water. Depending on the product, the cooling effect can last from a few hours to several days.
More expensive options may involve active cooling technology that requires a battery. Cool vests incorporate cooling packs fitted into the lining of a waistcoat-like garment, keeping the torso cool. Many of these are designed for athletes and are styled to be comfortable when active.
If you get hot at night, a cooling pillow may help, and there are plenty of options available. You can find regular pillows designed and made with cooler materials, but also pillows with cooling gel pads attached, or gel pads that you can put on top of your existing pillow. Memory foam can be heat-retentive and uncomfortable in hot conditions, so you may wish to save that for winter, or select a reversible option with a cool side and a warm side.
Home cooling equipment
Some people find equipment to cool rooms a great help during hot periods of the year, though there are a few points to be borne in mind before making a purchase.
Air conditioners use a refrigerant to lower room temperature. Permanent devices can be expensive, but there are cheaper, portable models available that can be set up where needed. Although very effective, air conditioners can be noisy, take up space and use a lot of electricity. As the process creates hot air, the device needs to be set up near a window so that this can be expelled.
Air coolers work by drawing air through water. Whilst these are much quieter than air conditioners and are also much cheaper to run, the cooling effect is less, particularly in humid conditions. To get the best from an air cooler it is worth investing in a more expensive model.
Cold sensitivity is less common with MS than heat sensitivity, and it tends to affect different symptoms. The symptoms most likely to be affected are nerve pain, mobility and spasms. Depression and fatigue may also be triggered by the cold, particularly if it co-incides with poor weather and less sunlight. Having increased spasticity or stiffness due to low temperatures can make walking in icy conditions harder.
If you have this sensitivity, you may find cold weather, cold draughts or having a fever affects you considerably. You may even find that driving with the window open triggers your symptoms.
Dealing with the cold
Choose clothing that you can layer up easily. This will help you stay comfortable, particularly if you are moving between places at different temperatures, such as in and out of shops on a cold day.
Scarves or hats with ear or neck protection will protect you from chilly draughts and may reduce nerve pain in the face and neck. A lightweight tube scarf can be pulled up or down as needed. You may find you use scarves all year round, not just winter, so look for something washable and compact.
Make sure you are eating well. Hot food and hot drinks will help keep you warm and give your body the fuel it needs to generate internal heat. Avoid too much alcohol, as it has the overall effect of cooling your body by causing your skin to flush and give off heat.
Try to ensure that your home is well insulated and heated. Simple tips like drawing the curtains at dusk and bleeding your radiators can help maintain the warmth in your home without extra cost.
Space heaters can be useful for keeping individual rooms warm, but they can be more expensive than central heating in terms of energy costs. Use space heaters safely at all times. Position them on a hard surface and keep bedding and furnishings well away. Many space heaters have safety features such as automatic cut-outs if they overturn or overheat.
Blankets, electric blankets and hot water bottles are useful to keep you cosy at home without all the other occupants having to sweat. Use electric blankets and hot water bottles safely, and be careful if your MS means that you don't detect heat well to avoid burns or scalds.
Don't forget to move around frequently to prevent muscle stiffness and improve your circulation.
There is a huge variety of clothing and equipment designed to either keep you warm or cool. An online search will provide you with lots of options, but as with any purchase, ensure that they are a reputable company, keep your banking and personal information safe, and seek personal recommendations where you can. Outdoor activity or clothing companies can also be a good source of heating and cooling products.
You may wish to ask other people with MS what products they have found useful, or ask your MS team for advice. Our Facebook peer support group has a large community you could ask.
Cooling products include wearable items such as neck wraps, neckties, vests or hats. These are often filled with gel that can be cooled in a fridge or used to store cold water. They need to be refreshed from time to time, but can be very effective. Cooling pillows use similar principles and can be effective in keeping you cool at night, or when sitting or lying in the same place for a while.
Home cooling products such as air conditioning can be a more expensive investment, but may be worth looking at. You could try screening out the sun with blinds or curtains when hot, combined with an effective fan to manage air flow through your home.
If you struggle to stay warm at times, then you will likely be looking for clothing and heating solutions. It can be more efficient to ensure that you don't lose heat, than to warm yourself up again if you have got cold, so prepare ahead each day. Dressing in thin, comfortable layers that you can add or remove easily allows you to adjust your temperature as needed. Hands, feet, head and neck are often especially sensitive to cold.
Personal heat sources such as hot water bottles, electric blankets or chemical heat packs can be helpful, but take care if you have reduced sensation or numbness in your skin, as you could damage your skin without being aware of it.
Your home will be less expensive to heat if it is well insulated and free from draughts. Blankets, thick curtains and draught excluders can help in older homes. You may also like to use additional plug-in space heating for your key rooms. Some space heaters are cheaper to run than others, so look for reviews that give the power output and electricity draw for items you are considering. It may be more cost-effective to turn up your main heating a degree or two instead.
- Journal of Applied Physiology 2010;109(5):1531-1537. Full article Thermoregulation in multiple sclerosis.
- Temperature (Austin). 2018 Sep 5;5(3):208-223 Summary Temperature sensitivity in multiple sclerosis: An overview of its impact on sensory and cognitive symptoms
- Handb Clin Neurol. 2018;157:701-714 Summary Thermoregulatory dysfunction in multiple sclerosis.
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