Strange Side Effects of Exercise: From Runny Noses to 'Coregasms'

Exercise is widely recognized for its numerous health benefits, boosting physical fitness and mental well-being. Engaging in regular physical activity can leave you feeling energized, refreshed, and ready to tackle daily challenges. However, for some individuals, the aftereffects of a vigorous workout may involve bizarre or unexpected bodily reactions.

Here are some of the more unusual phenomena that can occur due to exercise:

1. Metallic Taste in the Mouth
Many people notice a metallic flavor after exercising. This sensation results from increased heart rate and blood pressure, which can cause tiny blood vessels in the nasal passages to rupture. Blood from these vessels may flow into the throat, leading to the metallic taste caused by iron in the blood. Elite athletes, such as cyclists and ultra-marathon runners, often report this due to the strain on their lungs and circulatory system.

2. Bleeding from Unlikely Areas
Long-distance runners sometimes experience bleeding from the anus, a condition linked to altered blood flow distribution during intense activity. As more blood is directed towards muscles and vital organs, the gastrointestinal tissues may temporarily experience oxygen shortages, which can cause bleeding once normal blood flow resumes. Additionally, chafing from clothing or repeated impact can cause nipple or skin irritation, leading to bleeding—especially in cold weather or when sweating. Using lubricants like petroleum jelly can help prevent such issues.

3. Skin Rashes and Heat-Related Irritations
Sweating during exercise can trap dead skin cells, dirt, and microbes in the pores, causing heat rash or prickly sensations. Urticaria, or hives triggered by heat and physical activity, can also develop, manifesting as itchy, painful rashes that may require antihistamines for relief. Choosing loose clothing and exercising in cooler environments can mitigate these skin reactions.

4. Blackened Toenails
Repetitive impact and pressure on the toes during running, tennis, or dancing can cause toenails to turn black or fall off—a condition known as "runner’s toenail." Proper footwear that fits well and reduces toe friction is essential in preventing this issue.

5. Runny Nose
The increased airflow during exercise exposes the nasal passages to more irritants, debris, and microbes. In response, the body produces extra nasal fluids to clean out and protect mucous membranes, resulting in a runny nose. This is common among swimmers and those exercising in cold environments, such as cross-country skiing.

6. Red Eyes
Straining during weightlifting or intense physical exertion can elevate blood pressure, leading to burst blood vessels in the whites of the eyes—a condition known as subconjunctival hemorrhage. While it appears alarming, it's usually painless and heals within weeks.

7. 'Coregasms'
Some individuals experience sexual pleasure or orgasms—termed "coregasms"—during certain exercises, especially core or abdominal workouts. Women report these more often, but they can also occur in men during activities like cycling, weightlifting, yoga, or even walking. Factors such as anatomy, hormonal states, and the release of endorphins contribute to these sensations.

Most of these exercise-induced effects are temporary and manageable. However, persistent or severe symptoms should be evaluated by a healthcare professional. Understanding these unusual responses can help individuals exercise safely and with awareness of their body's reactions.

[source: https://medicalxpress.com/news/2025-10-runny-noses-black-toenails-coregasms.html]