Stress or discomfort from heat.
Heat often leads not only to fatigue and reduced concentration but also to digestive issues—particularly bloating. When the air temperature rises, the body prioritizes cooling itself: sweat glands work harder, the heart rate increases, and blood vessels dilate. All of these puts additional stress on the body, especially if you’re exposed to direct sunlight or in a stuffy environment. In such conditions, the nervous system can react with tension—even if you’re not consciously aware of it. This subtle stress caused by heat can directly affect the gastrointestinal tract. As a result, food may stay longer in the stomach and intestines, which promotes gas formation. For example, after lunch on a hot day, you might notice heaviness in your stomach or even painful bloating — even if the meal was something you’re used to.
Swallowing more air.
In hot weather, people tend to breathe faster and deeper, especially when they feel tired, thirsty, or are in a poorly ventilated space. When you talk, drink or swallow, you may accidentally swallow more air than usual. Excess air does not always come out naturally and can build up in the stomach and intestines, causing bloating and other unpleasant symptoms. This is especially noticeable when you gulp down water in an attempt to quench thirst quickly. Or, for instance, when chewing gum or talking while walking under the blazing sun—air swallowing happens almost unnoticed. As a result, a bloated or full feeling may appear soon after. To reduce the amount of air entering your stomach, it’s important to drink slowly, avoid talking while eating, and try to regulate your breathing on hot days.
Reduced efficiency of nutrient uptake in the gut.
In hot weather, the body shifts its focus—its main priority becomes thermoregulation, or cooling down. This causes changes in blood circulation: more blood flows to the skin to help release heat, while blood flow to internal organs, including the intestines, may temporarily decrease. As a result, digestion slows down and the absorption of nutrients and fluids in the intestines becomes less efficient. When the intestinal lining receives less blood, it functions less effectively. This can cause substances that are normally absorbed quickly to remain in the intestines longer. This delay creates favorable conditions for fermentation, leading to gas formation. For example, after consuming familiar foods—vegetables, fruits, or dairy products—you might experience bloating or abdominal discomfort on a hot day, even if those foods never caused issues before. People with chronic gastrointestinal conditions such as gastritis or gastroesophageal reflux disease (GERD) should be especially cautious in the summer. These conditions can be exacerbated during periods of heat, so it is important to remember to take medications prescribed by your doctor, such as Rebagen, Omez, Nexium, on time. Taking them regularly helps prevent flare-ups, reduces the risk of inflammation, and supports the digestive system’s stability even in challenging environmental conditions.
Increased consumption of carbonated drinks.
In hot weather, many people try to quench their thirst with cold beverages—very often, these are carbonated drinks such as sugary sodas, tonics, or even highly carbonated mineral water. They seem particularly refreshing, especially when chilled, but they can cause bloating. Carbonated drinks contain carbon dioxide, which forms the characteristic bubbles. Once in the stomach, some of this gas is released through burping, but a significant amount remains and accumulates, creating internal pressure. This effect is especially noticeable when a large volume of the drink is consumed quickly—your body simply doesn’t have enough time to release the excess air. Additionally, most carbonated drinks contain high amounts of sugar or artificial sweeteners, which can be poorly absorbed in the intestines. That’s why on hot days, it’s best to choose still water, drink it slowly and regularly, to maintain a sense of digestive comfort.
The impact of ultraviolet radiation on the microbiome.
Scientific studies have shown that ultraviolet (UV) radiation can indirectly alter the composition of the gut microbiota through the immune system and inflammatory responses in the body. For example, prolonged sun exposure can trigger immune activity that disrupts the balance between “good” and “bad” bacteria in the gut. When this balance is disturbed, digestion becomes less efficient: certain foods may break down more slowly or incompletely, creating conditions for fermentation. This leads to gas production and bloating, even after eating familiar foods. A simple yogurt or portion of fruit that caused no problems the day before may lead to heaviness and abdominal rumbling after a full day at the beach. Changes in the microbiome can also affect intestinal motility—slowing the movement of food through the digestive tract and further increasing gas buildup.