Have you ever experienced such hot summer days to the point that you feel lethargic and want to just laze about? On those kinds of days, it’s not uncommon for people to want to spend their whole day at the swimming pool or their own private pool. The relief that the escape from heat brings you can make you want to stay in the water for hours.
However, you may have noticed that when you exit the water afterwards, your skin comes out looking completely shriveled up and pale, like bleached raisins. Surely this is not good for your skin? Many people have experienced this with no long-term negative effects, but that doesn’t mean it’s safe.
An extreme example of this is, in WWI, soldiers were stuck in wet trenches for days and weeks on end with inadequate socks and boots to keep their feet dry. Many soldiers ended up with trench foot, a condition that causes such effects to one’s feet such as blisters, blotchy skin, redness, nerve damage, pain, and sloughing off of the skin. If your feet hurt to walk on after spending hours in the pool, this can be a symptom of trench foot.
In a skin-immersion study, it was found that serious damage can occur to the skin after only 12 hours of immersion. Prolonged water immersion for one week can result in similar effects as trench foot on the water-immersed skin. However, the same study discovered that the colder the water is, the less skin damage occurs.
Based on the study’s findings and anecdotal evidence, we can conclude that it is bad to stay in the pool for 12 hours or longer. That said, most people would naturally get out of the water long before that because they’ll get cold, hungry, thirsty, bored, etc. Therefore, in practice it is highly unlikely for a normal pool-goer to experience any major downsides to staying in the water for hours.
Why you shouldn’t be in the swimming pool for too long
Pool water is typically kept at a leisurely 78 to 82°F (26°C to 28°C), some a bit warmer, some a bit colder. For reference, the normal temperature for a healthy human’s core body temperature is 98.6°F (37°C).
As you can see, even though the pool water seems to be quite warm, it is actually significantly lower than our core body temperature. This is important to know because water is extremely effective at conducting heat away from the body, ultimately causing us to lose heat four times faster compared to air. If your body ends up dropping below 95°F (35°C), then you can suffer from hypothermia.
This is made worse if the pool is outdoors and you are getting out of the water and exposing your wet skin to the wind. The water on your skin will have an amplifying effect for the wind, causing you to feel extremely cold and further increasing your risk of hypothermia.
The longer you spend in the water, the more your core body temperature will drop. Even in “warm” water, you will likely end up shivering and with blue extremities as your body tries to concentrate its circulation to your core to keep the temperature as high as possible.
Continuing on from the previous point, if you spend so long in the water that your body reaches a state where it needs to shunt most of the blood from the arms and legs to the torso, robbing them of their oxygen, you will find it difficult to swim and tread water.
A more likely scenario is that you will be actively swimming or playing in the pool which uses up a lot of energy. After about an hour or so, you’ll probably feel very fatigued. Most people at this point would want to leave the pool already.
However, some people who are in the pool for training and fitness might want to push themselves further. They may have heard stories of how the greatest Olympian of all time, Michael Phelps, swam for three to five hours a day on his quest to earn as many Olympic gold medals as he could.
Unfortunately, you’re not Michael Phelps. And while nobody knows the exact details of his training regimen, I highly doubt he would swim that long in a single session. So don’t spend so long in the pool pushing yourself past your limits because you are just increasing your risk of drowning.
If you’re spending a lot of time in an outdoor pool, then you have two things to worry about: the water and the sun.
You can get tanned and sunburned through water, so you will need to apply waterproof sunscreen before you go in for a dip. You should apply it at least 15 minutes beforehand so that the sunscreen can get absorbed into your skin.
Many people make the mistake of entering the water after applying sunscreen and having it washed off immediately, as well as sitting or lying down and having parts of it rub off on surfaces before it has a chance to get absorbed into the skin.
Sometimes the problem is simply forgetting to apply it on certain areas, applying it unevenly, or being incapable of applying it to some areas (most commonly the back). It’s best if you had someone help you apply the sunscreen on these hard to reach areas so that you don’t miss anything or apply it unevenly.
Another common mistake is not re-applying sunscreen at the specified times (typically every 60-90 minutes) because sunscreen does not last the whole day. Don’t have so much fun that you forget to wear sunscreen.
Being in the cool, refreshing water can hide the fact that you’re actually sweating a lot. As mentioned, swimming or even just moving around in the water is great exercise due to the water resistance, and this will cause you to sweat. In other words, you’re losing fluids without realizing it.
Furthermore, being submerged in the water can cause you to experience immersion diuresis which makes you want to pee. (Hopefully you aren’t peeing in the pool.) If you are sweating a bunch and peeing a bunch and you aren’t replenishing your fluids, then you’re getting seriously dehydrated the whole time.
Water is necessary for your body to function properly. Being dehydrated can often lead to cramps, which are a major drowning risk whenever you’re in the water. It also generally leads to poor performance and lack of energy when swimming. If you experience dizziness, headaches, dry or sticky mouth, muscle cramps and so on, you need to get some fluids in you immediately.
Staying in the pool for too long can lead to skin damage. If you are a frequent pool-goer, chlorine is known to cause dry skin, and possibly even rashes, blisters, and chemical burns if there is too much chlorine in the pool.
You can also suffer extensive skin damage by staying in the pool for too long in a single session. As mentioned in the introductory paragraphs, spending 12 hours or longer in the pool in a single session can cause skin damage like numbness, blotchy skin, swelling, a prickly sensation, and even pain. Staying even longer than that (e.g. multiple days), and the skin can die and slough off.
Why most people leave the pool early enough
It would take extreme effort and dedication for someone to spend more than a few hours in the pool, let alone 12 hours or more. Many people will be forced to leave the pool on their own naturally for many reasons which I cover below.
Boredom. The most obvious reason most people leave the pool is when their family or friends are leaving, they just leave with them. You can go to the pool yourself, but you probably won’t stay there for many hours alone.
Fatigue. Swimming is an incredible exercise that can burn as many calories as jogging. Even if you’re wading through the water instead of swimming, the water resistance alone makes even basic movements underwater more laborious than on land, and that alone uses up energy. At some point you’ll feel too tired and just want to get out of the pool.
Dehydration. Similar to the point above, exercising is going to cause you to sweat and you’re going to need a bunch of water to keep your bodily functions working properly while exercising. In order to replenish lost fluids, you’re going to have to get out of the water occasionally to drink water. If you’re drinking a lot of water, you’re also going to want to pee (hopefully not in the pool) which is yet another reason to leave the water.
Hunger. Most swimming pools provide access to water fountains so that you can stay hydrated. However, they do not provide access to food except for vending machine snacks, nor do they allow food in the pool. Therefore, at some point your stomach is going to growl and you’re going to leave the pool to grab a bite to eat.
Cold. Our core body temperature is much higher than the water, therefore every second you spend in the water is actually causing your core temperature to drop ever so slightly. At some point your core temperature will drop enough that you start shivering, and if you keep ignoring that, then you can get hypothermia. Most people exit the pool way before that happens so that they can go to the hot tub, sauna, or steam room.