Why Your Body Feels Hot After Swimming (Explained!)


If you’re an avid swimmer, you’ve more than likely experienced a feeling of post-workout body warmth after hopping out of the pool at some point. Such a noticeable raise in body temperature can be somewhat strange, and even concerning. This begs the question, why does it even happen?

You may notice a raise in body temperature after leaving the pool because heat is a natural by-product of energy production in the body. Once you leave a chilled pool, this feeling of warmth is magnified since there’s no cold water present to cool you down. In extreme cases, you may be overheated.

The plausible explanations of feeling hot after a swim are analyzed in further detail below. Read until the end to find out how much time it usually takes for your body to cool down to normal temperature, along with helpful tips on how to effectively manage your body temperature post-swim.

Possible Causes of Feeling Hot After Swimming

Natural Body Temperature Response to Exercise

As a direct consequence of exercise, the body must manufacture additional energy to keep up with the physical demands that it has been tasked with doing. Heat is a natural by-product of this energy production process. Over the course of a workout, this heat accumulates and the internal temperature of the body raises as a result.

To rid the body of this excess heat, the body employs several specific physiological responses simultaneously (source):

  • Sweat Evaporation – To quickly dissipate internal heat, the body sweats. Human skin has a large amount of surface area, so as more and more sweat is exposed to the air, there’s ample opportunity for internal heat to escape through the process of evaporation.
  • Increasing Blood Flow to the Skin – The body also shunts blood to the skin. As sweat on the skin cools, it also cools down the temperature of the skin and the blood nearest to the skin. For this reason, the natural propensity of skin blood flow to warm the skin is neutralized by the natural propensity of sweating to cool the skin.

Although swimmers are surrounded by cooled water, they still implement these same physiological mechanisms to lower core body temperature. It’s just a bit harder to notice when you’re sweating in the pool because you’re completely immersed in water already. This can skew your perception of how hot your internal body temperature truly is.

Chilled swimming pools help to regulate core body temperature by cooling down the increased blood flow to the skin. In essence, the chilled water acts like body sweat, in that it neutralizes the natural inclination of skin blood flow to warm the skin by cooling it down. This is the main reason why lap pools are intentionally set to be more cold than recreational pools.

At the end of your swim workout, your internal body temperature will likely be at or near its peak. As you leave the chilled pool water behind, you will not have the luxury of cold water to moderate the warm blood flow to the skin.

Plus, although your body may be sweating slightly, it is not sweating nearly as much as it needs to be since it was relying on the cold pool water to keep the warmth at bay.

For these reasons, the body experiences a surge of warmth upon leaving the chilled recesses of the pool. It takes time for the body to adapt to its new surroundings and initiate the necessary physiological changes to lower its core temperature. Unfortunately, this means that you have to endure this sudden rush of body warmth as your body goes through this readjustment period.

Heat Exhaustion

Under some circumstances, this excess body warmth may be more extreme than your body’s average response to exercise. Your body may instead be experiencing the negative effects of heat exhaustion.

Many people are under the false impression that swimmers cannot suffer from heat exhaustion since they’re immersed in water. It is well within the realm of possibility for a swimmer to suffer from heat exhaustion, especially if they’ve been physically exerting themselves for an especially long workout.

Other factors may increase the risk of heat exhaustion in swimmers besides workout intensity and duration.

One of these factors is dehydration. Since swimmers fail to realize how much they sweat during their sessions, they don’t rehydrate nearly enough over the course of their workout. Sadly, the skin does not soak up water like a sponge, so being surrounded by water has no effect on your hydration status (source). As a result, swimmers are often at greater risk for dehydration—and heat exhaustion—relative to other land-based athletes.

Furthermore, the water temperature of the pool itself can play a critical role in the likelihood of heat exhaustion. Lap pools are deliberately chilled to approximately 78 degrees Fahrenheit to cool down the warm blood that flows to the skin to counteract any rise in core body temperature. Rigorous swimming in a body of water that’s 82 degrees Fahrenheit and above can be especially dangerous, as there’s not much opportunity for the skin to dissipate heat any longer (source).

If a swimmer is both dehydrated and swimming in a warm body of water, severe hyperthermia or heat stroke may even be possible. In this dangerous scenario, the body temperature regulation processes of the body fail, resulting in severe damage to vital organs and possible death (source).

Even the best swimmers in the world are not exempt from this. Fran Crippen, a world renowned swimmer formerly on the U.S. National Team, suffered from heat exhaustion and passed away in an open-water race event near Dubai in 2010 at the young age of 26. Reportedly, the water temperature was in the mid-to-high 80s—conditions that are conducive to hyperthermia (source).

You should seek medical help immediately if you encounter any of the subsequent heat exhaustion symptoms after swimming (source):

  • excessive sweating
  • weakness
  • nausea
  • vomiting
  • headache
  • lightheadedness
  • muscle cramps

How Long Does It Take to Cool Down to Normal Temperature?

Under normal conditions, the body should cool back down to its normal core temperature without any external intervention. You will not have to implement any drastic measures to rid yourself of any excess body warmth. All you will have to do is wait patiently for the physiological response of the body to do its job.

On average, core body temperature should return to normal within twenty minutes of finishing exercise. Until then, you’ll simply have to bear the burden of feeling abnormally warm.

(source)

If body warmth persists after this twenty minute waiting period, you should seek medical help, as heat exhaustion may be responsible instead of normal temperature regulation mechanisms.

Tips on How to Deal with Post-Swim Body Warmth

Although it can be difficult to completely get rid of post-swim body warmth, there are a few strategies you can implement to minimize this effect. The most effective of these strategies are described in greater detail below.

Drink 8 oz of Water for Every 20 Minutes that You Swim

As discussed earlier, dehydration is a common problem for swimmers, which could lead to some serious repercussions towards the end of the workout session, such as excessive body warmth and heat exhaustion.

In order to keep the body at a stable core temperature, it is solid practice to drink water during the swimming session itself. This way, you can replace the fluids you’ve gradually lost over the course of the workout through sweating.

As a general rule of thumb, you should be drinking 8 oz of water for every 20 active minutes of swimming (source). Having this specific goal in mind will at least keep you conscious of your hydration levels, something that many recreational swimmers overlook.

It’s also highly recommended that you drink water before the swim and after the swim to greatly reduce the chances of dehydration. Bringing a water bottle every time you head to the pool will make this entire process easier on yourself.

Spend 5 to 10 Minutes Cooling Down

Another effective tip to stave off post-swim body warmth is to devote the end of your swimming workout to cooling down. For whatever reason, most swimmers will take the time to warm up, but they won’t take the time to cool down.

The cool-down is equally as important to the warm-up, since it helps to ease the physiological parameters of the body back to normal. By cutting off a swim immediately and exiting the pool, you leave no time for your breathing pace and heart rate to slow down. Instead, your body remains in a highly active state, causing core temperature to stay elevated even when you’re well away from the water.

The first step to a proper cool-down is to gradually slow down your swimming pace and scale back the intensity level. It may even be in your best interest to switch to a less physically taxing swimming stroke, such as the breast stroke, to give time for the body to recover.

Afterwards, static stretches can also aid in the cool-down process. You should structure your stretching regimen so that any lagging points in your mobility are addressed first. Aside from the benefits in range of motion and body temperature regulation, stretching can accelerate recovery time and prevent future injury as well.

Swim in Pools Chilled to 78 degrees Fahrenheit

Lastly, you should only perform exhausting swim workouts in chilled waters. The general guideline for fitness swimming pools is 78 degrees Fahrenheit, according to American Red Cross (source).

Most fitness swimming pools feature this lower temperature to ensure the personal safety of all swimmers. In outdoor bodies of water, such as oceans or lakes, the water temperature can be variable. You should take greater care when swimming long distances in these waters because internal heat can build up rather quickly in this type of aquatic landscape.

If given the choice, always choose lap pools over recreational pools for swim workouts. Recreational pools are typically two to three degrees Fahrenheit warmer than a standard lap pool. This temperature difference may seem trivial, but it can help tremendously with minimizing any excess body warmth once you leave the comforting coolness of the water behind.

The Bottom Line

In most cases, the normal temperature regulation mechanisms of the body are to blame for feeling hot after a swim. However, there are certain scenarios where this body warmth can be attributed to a more serious condition, such as heat exhaustion.

Be mindful of your hydration levels, your training structure, and the water temperature of the pool, as these factors can help to ward off uncomfortable feelings of warmth post-swim. Above all else, keep progressing on your swimming journey!

All content written by HydroPursuit is for informational purposes only. The material found on this site is not intended to replace professional medical advice, treatment, or diagnosis. Consult with an accredited health care provider prior to initiating a new health care regimen.

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Austin Carmody

I am the owner of HydroPursuit. I enjoy kicking back and getting out on the water as much as I can in my free time.

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