Oct 10, 2025 12:00:00

Explains seven abnormalities caused by intense exercise, including a metallic taste in the mouth, runny nose, and sexual pleasure

While exercise has a positive effect on the mind and body, sometimes intense exercise can cause strange physical symptoms.

Adam Taylor , a professor of anatomy at Lancaster University in the UK, explains the symptoms that can be caused by intense exercise, such as a metallic taste in the mouth, a runny nose, and sexual pleasure.

Runny noses, black toenails and 'coregasms': here are seven weird ailments that exercise can trigger
https://theconversation.com/runny-noses-black-toenails-and-coregasms-here-are-seven-weird-ailments-that-exercise-can-trigger-265694

◆1: Metallic taste in the mouth
Some people experience a metallic taste in their mouth after exercise. This is because the elevated heart rate and blood pressure caused by exercise can cause tiny blood vessels in the nose to burst over a prolonged period. This can result in a nosebleed or blood in the throat, the latter of which can cause the metallic taste in the mouth due to the iron in the blood.

Some evidence suggests the metallic taste may also be caused by small blood vessels in the lungs bursting, which may be caused by prolonged lung strain and is most common in cyclists and marathon runners , Taylor explains.

◆2: Bleeding from the anus or nipples
Exercise can also cause bleeding from unexpected places, such as anal bleeding during long-distance running. At rest, about 25% of the blood pumped by the heart goes to the digestive tract, but during exercise, blood supply to the muscles, heart, and lungs increases, reducing blood supply to the digestive tract by about 80%.

However, once blood flow returns to normal after exercise, a sudden increase in blood flow to the digestive tract can damage small blood vessels, resulting in bleeding from the anus, which can be serious and even life-threatening .

Nipples are one of the areas that can bleed when rubbing against clothing during running and other activities. The more distance a person runs per week, the more likely they are to experience nipple bleeding, with approximately 40% of people who run 65km or more per week having experienced nipple bleeding. In cold weather, the nipples become erect, concentrating contact points with clothing and increasing irritation, worsening bleeding. Sweat also weakens the protective barrier on the skin's surface, worsening the symptoms. To prevent nipple bleeding during running, Taylor recommended 'applying Vaseline to the nipples to reduce irritation.'

◆3: Rash
When you exercise, your body sweats to cool itself down, but if dead skin cells, dirt, or microorganisms trap the sweat in your pores under the skin, it can cause

a heat rash (prickly heat) . Heat rash will go away on its own over time, and can be prevented by wearing loose clothing during exercise, exercising in a cool environment, and cooling down afterward.

Exercise can also trigger hives , which are more painful and itchy than heat rash. Hives are caused by the release of the immune chemical histamine after exposure to a trigger, and antihistamines are often needed to relieve the symptoms.

◆4: Darkening of toenails
People who participate in sports that put repeated impact or pressure on the toes, such as running, tennis, or dancing, may experience darkening and peeling toenails. This condition, commonly known as 'runner's toenail,' can be prevented by wearing shoes that are properly sized and prevent the toes from being crushed.

◆5: Runny nose
The increased rapid breathing that occurs during exercise increases the number of irritants, debris, and microorganisms that enter the body through the nose, which can result in a runny nose as a defense mechanism. Exercise-induced runny nose is common in swimmers, cross-country skiers, and others who exercise in cold climates that are harsh on mucus membranes.

6. Red eyes
Lifting heavy objects or straining yourself during exercise can cause a sudden rise in blood pressure, which can burst the small blood vessels in the white of your eye, resulting in a phenomenon known as

subconjunctival hemorrhage . This causes red spots to appear in the white of your eye, but fortunately, this condition is not painful or affects your vision and will resolve within a few weeks.

◆7: Sexual pleasure (coregasm)
Exercise can trigger a sexual sensation known as a 'coregasm.' While core exercises like abdominal exercises often trigger coregasms, some women have also experienced coregasms during cycling, weightlifting, running, yoga, and even walking.

Women are generally more likely to experience coregasms than men, but research is limited, so it's unclear how common they are. Coregasms are thought to be influenced by a person's anatomy, physical, physiological, and psychological state, and may also be related to the release of feel-good neurotransmitters, such as endorphins , during exercise.

'The good news is that most of these exercise-induced discomforts are temporary and can be easily corrected at home on your next day off. If they don't go away, you should see a doctor or nurse,' Taylor said.