When the weather gets colder, many people like to take advantage of the chilly temperatures by going for a swim. But is swimming in cold water bad for you?
As a general rule, cold water itself does not make you sick unless it is so cold you suffer from hypothermia. It is the bacteria and viruses that live in the water that cause the most common illnesses, such as the flu or the common cold.
I have recently discovered the bliss that is cold water swimming and I have never felt as healthy, but is that just a coincidence?
In this article, I want to look at the potential health risks of swimming in cold water, covering the following:
- Can you get sick from swimming in cold water?
- Can you catch a cold from being cold and wet?
- Is it better to swim in cold water or warm water?
- What happens if you stay in cold water too long?
- How to avoid getting sick from swimming?
Can You Get Sick From Swimming In Cold Water?
Cold water itself does not make you sick unless it is so cold that you suffer from hypothermia.
Many swimmers believe they will catch a common cold or the flu if they swim in cold water. However, the cold water does not make you sick; it is the bacteria and viruses that live in the water that can cause illnesses such as the flu or the common cold.
In recent years, research is suggesting that cold water swimming is good for you, with many studies citing the benefits of cold water swimming, including: [source]
- A strengthened immune system
- Energy boost
- Improved circulation
- Improved libido
- Reduced stress
The greatest health risk from cold water is hypothermia. This is a medical emergency that occurs when your body temperature drops below 35°C (95°F) [source]
Hypothermia & Cold Water Swimming
Hypothermia is a really serious condition. Hypothermia can occur in any body of water that is lower than 21°C (70°F) [source]
Hypothermia can range from mild to moderate to severe, with a high risk of death if untreated.
Always take care if swimming in water that is less than 21°C (70°F).
For many cold water swimmers out there, 21°C (70°F) may seem warm, however, below a temperature of 25°C (77°F) our breathing starts to be affected. For beginners new to the sport, approach cold water with care.
I have covered the effects of hypothermia, what to watch out for and how long you should stay in cold water in much greater detail in this article, “How Long Should You Stay In Cold Water? (When to get out)”
Can You Catch A Cold From Being Cold And Wet?
Most cold water swimming is done outside as the vast majority of indoor pools are heated.
With cold water swimming, be it in freshwater or in an unheated outdoor pool, being cold and wet is part of the experience.
Can we catch a cold from being cold and wet after our swim?
You cannot catch a cold from being cold and wet. Having wet hair outside or after your swim will not give you a cold or the flu. It is bacteria and viruses that cause the common cold and most common illnesses. [source]
As a child, my mother would always warn me not to go outside with wet hair, as she believed I would get sick, but this is a very common urban myth.
For years, I believed this myth, but it is just not true. The cold and wet is not our enemy, the viruses and bacteria are.
Is It Better To Swim In Cold Water Or Warm Water?
Swimming is a wonderful exercise and whether you do it in warm or cold water, you will feel a health benefit.
Below are the most common benefits of swimming in both cold and warm water.
Cold Water Swimming Benefits
1. Immune System Boost
Swimming in cold water can boost your immune system. This is widely documented in various academic papers. [source]
It has been shown that infectious diseases of the upper respiratory tract are 40% lower in winter swimmers compared to control groups. [source]
It is also argued that the stress the body undergoes when exposed to cold water releases stress hormones which stimulate the body to fight infections. [source]
This area is still under investigation by researchers to understand exactly what cold water does in the long term but for years, cold water swimmers claim they suffer less sickness since starting their cold water swimming, and it appears there could be some real truth in this.
2. Burns More Calories
Because we have to work so much harder when we swim in cold water, we will burn more calories in cold water.
When we get into cold water, our heart must work harder and circulation is restricted. In order to keep warm, our body has to do more work, which results in a greater calorie burn.
3. Improved Mood
Swimming in cold water has been shown to improve our mental outlook, inducing a positive attitude.
Cold water swimming has been used as a treatment for depression. For example, this study documents the journey of a 24-year-old who suffered from depression who came off all medication and has remained medication free after a prescription of regular cold water swimming. [source]
Because cold water swimming activates the sympathetic nervous system, cold water swimming could be used in the treatment of depression. [source]
Although I hate getting into cold water, I always feel elated after my swim and on top of the world, so I definitely feel a positive mood boost from the cold water.
4. Lowers Blood Pressure
When first getting into cold water, your blood pressure will rise. This is the most dangerous point as many fit people can get a heart attached because of the cold water shock at this initial stage.
However, outside of the initial cold water shock, some studies suggest that cold water swimming can lower blood pressure for long-term cold water swimmers. [source]
This is still in debate, however, this study looked at long-distance swimmers who swam in 10–14°C water over four days. On the fourth day, their diastolic blood pressure was significantly lower. [source]
Warm Water Swimming Benefits
Swimming in warm water also has lots of significant health benefits.
Of course, swimming in warmer water is much easier and also less dangerous as you will not be exposed to the threat of hypothermia.
Here are some benefits of swimming in warmer water:
1. Relaxed Muscles
Unlike cold water, where your muscles will tense and contract, your muscles will easily relax in warm water.
This induces a feeling of calm and a more fluid swim.
If you have a fear of water or learning to swim, then it is best to stick to warm water until you are very experienced to allow your body the best opportunity to relax in the water.
2. Easier To Workout
Although cold water burns more calories per hour than warm water, it is much easier to get a full intense workout completed in warm water.
Many cold water swimmers, even the most advanced, will only stay in very cold water for a minimum amount of time, often just a few minutes. This leaves less time to get a long swim in.
In warmer water, you can enjoy a longer swim and work hard to get your heart rate up as you are not concerned about hypothermia or having to get warm.
3. Improved Circulation
In cold water, your blood vessels will contract in order to conserve energy which restricts blood flow. This happens as part of the cold water shock syndrome. [source]
In warm water, your blood vessels will not do this and you benefit from improved circulation and blood flow.
What Happens If You Stay In Cold Water Too Long?
If you stay in cold water for too long or go into water that is too cold, you will risk getting hypothermia.
Signs of hypothermia include: [source]
- Violent or uncontrollable shivering
- Slurred speech
- Pale skin
Symptoms of hypothermia range from mild to severe. Hypothermia can kill.
We all have different tolerances to cold water, so it is very difficult to find a good recommendation for how long you should stay in cold water.
The length of time you spend in cold water will depend on factors such as the water temperature and the warmth protection of the swimmer.
If you are unsure or find the water too cold, only take a quick dip and limit your exposure.
If you are still cold after 10 minutes, it is best to get out.
Treat any water with a temperature of less than 21°C (70°F) with caution.
To learn more about cold water and how long you should stay in cold water, check out this article, “How Long Should You Stay In Cold Water? (When to get out)”
How To Avoid Getting Sick From Swimming?
There are certain things we can do as swimmers to reduce the risk of picking up infections or getting sick from swimming, both in warm or cold water.
1. Don’t Swallow Water
As mentioned, it is the bacteria, germs, and viruses in the water that cause illness and not the temperature of the water itself.
If you swallow contaminated water, you will get sick, so it is best to avoid swallowing water if you can help it.
One of the most common illnesses from swallowing contaminated water is diarrhoea.
In order to keep both you and the pool clean, it is important to shower both before and after your swim.
Showering before your swim will stop you from bringing germs and contaminates into the pool, and showering afterwards will clean your skin from any germs or contaminates.
One of the most common illnesses from not cleaning skin fully after a swim is a skin rash. Due to poor pool water standards, skin rashes can also start in the water.
3. No Open Wounds
The secret to not getting sick from your pool water is to ensure that it does not enter your body.
If you have any cuts or wounds, ensure they are fully and properly covered. There are many waterproof bandages on the market which can help.
4. Swim When Healthy
I love to swim as much as possible, but there are days when we all feel run down or tired.
I avoid the pool if I don’t feel in good form.
Not only does this protect other swimmers from any bugs or cold viruses I am carrying, but if you swim when run down, your immune system is more susceptible to any bacteria or virus infections in the water.
It is best to take a break and recover.
5. Dry Your Ears
Ear infections are one of the most common illnesses picked up while swimming.
I have had my share of ear infections from swimming over the years and it is something you will want to avoid.
The best way to avoid getting an ear infection from the pool is to ensure your ears are thoroughly dry after your swim.
As we swim, it is normal for water to get into our ears, but ensure you allow this water out before getting changed.
I have covered swimming ear infections, ear plugs and what you can do to reduce the risk in this article. Do Swimming Ear Plugs Stop Water Getting In Ears?
Swimming in cold water can be a refreshing and exhilarating experience.
Cold and clean water does not make us sick unless it is so cold that you get hypothermia from the cold.
General sicknesses such as diarrhoea, ear infections, skin rashes and cases of flu which can be contracted in an unclean pool are a result of bacteria and viruses in the water and not the temperature of the water.
To avoid such illness it can be useful to know what to look for to determine if a public pool is clean. I have covered this in more detail in this article, How To Know If Public Pool Water Is Clean (A step-by-step checklist)
Cold water swimming is a very enjoyable experience and although it can carry the risk of hypothermia due to the cold, general illness is not more likely in a cold pool.