How the time of the day impacts the immune system and Hashimoto’s

Have you ever heard of a circadian rhythm? A circadian rhythm indicates changes in the body that coincide with the time of the day — or more precisely with the earth’s daily rotation and exchange of light and dark periods — and it happens in virtually every cell of our body (1).

This daily rhythm helps us use our body’s energy in a more efficient way. Metabolism, memory, and the immune system are also under the influence of a daily rhythm (2–5).

Hormones, including epinephrine and norepinephrine, regulate our circadian rhythm and how our organs, tissues, and glands behave each minute of the day (6, 7).They also decide how the immune system will behave during day and night (8). The number of immune cells present in our bloodstream changes dramatically depending on the time of the day (9).

Cortisol, epinephrine, and molecules triggering inflammation are the highest at the time when waking up from a night’s sleep (10, 11).

Leukocytes — immune cells that help us fight infections — are mostly active during our awake time, which is because we are more likely to be exposed to viruses or bacteria during the time we are awake (12).

How can this daily immune system rhythm impact your symptoms?

Some autoimmune conditions make morning times more problematic, which is likely because of an increased number of molecules that promote inflammation (13, 14).

Disrupting your circadian rhythm through sleep interruptions or traveling across the time zones can contribute to a weakening of your immune system.

Time of the day is important for taking prescription medication — taking drugs at a specific time of the day can help improve symptoms and will cause the least side effects for some autoimmune conditions (15- 18).

A deregulated immune system — connected to autoimmune-caused symptom flare-ups — can also deregulate your circadian clock (19, 20).

More research is needed to understand the full extent to which the circadian rhythm might impact Hashimoto’s, and it’s likely that in different stages of Hashimoto’s one might feel the symptoms at different times of the day, as they can be caused by different types of immune cells.

What can you do to understand your own circadian rhythm?

  1. Try to figure out the best time for you to both go to bed and wake up. Try going to bed at the same time for at least two weeks, and waking up at the same time. Try to sleep at least for 7 hours. If you feel like you have gotten a good night’s sleep, then you have found your perfect time zone. If you sleep 7 or more hours, but still feel tired, it might be because you are not following your circadian rhythm.

  2. Try to establish if there is a specific time of the day to take your medication that results in you feeling better and with less side effects.

  3. Have a regular daily physical activity, whenever you can fit it at first, then experiment with times, durations, and intensities.