The Circadian Rhythm Effect
The human body is kept under almost steady conditions at all times (the concept of homeostasis). At their best, the hormonal and neural responses help to maintain this state of the body. But, when a cold attacks, the balance is distorted and the body finds ways to return to its previous state. This is where the immune system plays a major role. These hormonal and immune responses of your body to the effects of the cold symptoms you’re having are the reasons you might feel worse at night than during the day. This is because most of the chemicals in charge are influenced by the body’s own circadian rhythm. Inflammation of the concerned areas is likely to occur at night or in the wee hours of the morning since the immune system is putting up a fight against the infection. The immune system is very active at night (owing to the circadian rhythm), and this activity raises the temperature of the body. This is why you might feel the symptoms of nasal congestion and headache even worsen at night. [3]
