February 06, 2019
The real tell-tale sign that you’re actually sick — and not just *trying* to fight it off — is how you feel at night because, for some reason, you always feel worse at night.
Turns out, feeling more sick at night is a research-backed thing — apparently, your body’s circadian rhythms (plus, some other factors) can exacerbate your symptoms after sundown.
Your body’s circadian clock helps manage your immune system, Michael Smolensky, a biological rhythm researcher and adjunct professor of biomedical engineering at the University of Texas, tells TIME. “When the immune system is activated” — like when you’re sick with the common cold — “its infection-fighting cells release a variety of chemicals, some of which induce inflammation in the infected tissues,” he explains.
Smolensky says that this immune system activity and the inflammation it produces is not constant, but instead is “highly circadian rhythmic.” As a result, symptoms tend to be worst during sleep, when your immune system kicks into high gear.
You can also think of immunity as a 24-7 process. During the day, one branch of the immune system called cellular immunity is at the forefront of the defense. As we get ready to rest at night, another arm known as inflammation takes over. Usually, we don't feel the effects of cellular immunity, but inflammation is undeniable as it promotes fever, mucus production, reduced breathing capability and physical fatigue, Huffington Post reports.
The worsening of symptoms at night are made noticeable by the fact that during the day, your immune system tends to mellow out. It’s not unusual to feel a bit better around those times, but then to have symptoms come back with vengeance later at night.
On the flip side of being up and about during the day, at nighttime we tend to lay down or recline, which experts agree will cause your cold or flu symptoms to worsen, namely because your mucus has nowhere to drain. Help yourself out by adding an extra pillow which will help promote sinus drainage, some experts suggest.
Additionally, we can’t forget the power of the mind in this equation. Your daily life can be extremely hectic, with little time for yourself. Going from one task to the next doesn’t leave much time to dwell upon your symptoms. In evenings when you have time to relax and unwind, however, is when the mind has time to wander.
Of course, there are plenty of ways to fight a cold while it’s making you feel terrible at nighttime. Herbal remedies, over-the-counter medicine and vitamins may help, but nothing does the trick like rest, fluids and antioxidant-rich foods, according to Mayo Clinic.