The Future of Circadian Rhythms in Healthcare (Chronomedicine)

Sleep is heavily influenced by your circadian rhythms, but it’s not the only function in your body that falls into that category. In fact, circadian rhythms govern almost every process our body carries out over the day, including metabolism, immune response, DNA repair, and physical performance.

One topic that’s been getting a lot of buzz lately is the influence of circadian rhythms on how effective treatments are and how many side effects you experience while on that treatment. It turns out that taking a medication at 7am or taking that same medication at 6pm might mean you experience dramatically reduced side effects—or dramatically larger benefits. This is the idea behind “chronomedicine.”

While many of the drugs and treatments with known time-of-day effects are related to cancer, such as chemotherapy, the field is still mapping all the potential conditions out there that can benefit from timing. The fact that 80% of drugs act on targets that oscillate over the course of the day suggests that the potential could be pretty huge. We can also include preventative care in our scope: in a study published in 2016, researchers found that people who received influenza vaccines between 9am and 11am had higher levels of anti-flu antibodies one month later than people who received vaccines between 3pm and 5pm.

The effects of timing have implications on how we even measure the effectiveness of drugs. In a study from 2020, researchers from Harvard Medical School found that some preventative stroke strategies may have failed in humans because the rats they were initially tested on are nocturnal. Since rats are inactive during the day and active at night, they respond differently to treatments given during the day than humans would.

Difficulties with applying this knowledge are twofold. The first is the challenge of being able to accurately estimate a person’s circadian rhythms. While most people’s circadian rhythms have roughly adapted to the 24 hour cycle of day and night, our individual rhythms can vary significantly from one another. Across people who work during the day, circadian rhythms can vary by as much as 7 hours from person to person. If you work night shifts, that variance could be up to 24 hours. So if circadian rhythms are so variable, how can we give accurate circadian recommendations?

We built Shift to make this a possibility. Regular readers already know that Shift works by estimating your circadian rhythms through your phone and wearable data. From there we can help you change your circadian rhythms to better suit the sleep schedule you’d like to be on—whether that means helping you adjust faster to your next three night shifts or optimizing your schedule so you can finally get more than 4 hrs of sleep after a grueling shift. 

By estimating a person’s circadian rhythms in this way, we have made circadian estimations available to everyone with a smartphone. We hope that in the future you’ll be timing treatments and medications with our algorithms for tracking body clock time, which are 3x more accurate that methods based on wall clock time or bedtime.

Okay, but what’s the other challenge with taking chronomedicine into the real world? Adherence. The second difficulty often cited with chronomedicine is the fact that patients must adhere to these recommendations about their circadian rhythms to get the benefits. The thinking by some experts is that since people have enough trouble remembering to adhere to treatment plans without timing recommendations, the additional complexity of intentionally timing them is too much of an ask. 

We believe in patients’ desire to improve their outcomes and reduce their side effects, just like how shift workers desire to improve their sleep and prevent lasting health detriments. We even think that the fact that our recommendations are dynamic—that they change daily in response to the signal from the user’s devices and inputs—holds potential to improve engagement and increase adherence to treatment plans. That’s why we’re so focused on making sure Shift is built for the user. We are putting the science of technology into the hands of everyday people.

We’re starting with sleep and following circadian science to the expanse of human health. Follow our journey by subscribing HERE.