Final answer:
High humidity prevents efficient sweat evaporation which is necessary for body cooling, leading to a sensation of feeling hotter. In low humidity, while cooling is more effective, excessive drying can occur. It's crucial to maintain hydration and be aware of the body's reaction to varying humidity levels while exercising.
Step-by-step explanation:
Humidity plays a significant role in how our bodies perceive and adapt to high temperatures during exercise. When the humidity is high, the air is already saturated with water vapor, which reduces the evaporation rate of sweat from our skin. Evaporation is a cooling process; when it occurs, it helps lower the body's temperature. However, on humid days, this cooling effect is less efficient, making it feel much hotter than it does on dry days where sweat can evaporate more readily.
On the contrary, in low humidity conditions, while the evaporation of sweat is more effective, potentially leading to quicker cooling, it can also lead to discomfort due to the excessive drying of mucous membranes and an increased risk of respiratory infections. Thus, it's important to stay hydrated and be mindful of the body's response to different environmental conditions during physical activity.