When it comes to surgery, keeping patients safe and comfortable is a top priority. One important part of this process is giving medication to help people relax and reduce their memory of the procedure. A drug called midazolam is often used for this. It helps calm nerves and causes short-term memory loss, making the experience less stressful for patients.
But now, new research from the University of Colorado has revealed something surprising about this common drug. The time of day that midazolam is given might change how it affects the body—especially the heart.
The researchers looked at data from over 1.7 million surgeries where midazolam was used. What they found was unexpected: surgeries that took place at night were linked to a higher chance of heart damage. This was true even for patients who were otherwise healthy.
Why would this happen? The answer lies in how our bodies work on a natural 24-hour cycle, known as the circadian rhythm. This internal clock helps control many body functions, including sleep, hormone levels, and how our organs respond to stress.
One gene that plays a key role in this cycle is called PER2. This gene helps protect the heart and is more active during the day, thanks to light signals that help set our biological clocks.
The study found that midazolam can reduce the activity of the PER2 gene, especially when it’s given at night. When PER2 levels drop, the heart becomes more vulnerable to damage. So even though midazolam is doing its job in calming the patient, it may also be lowering the body’s natural protection against heart injury during nighttime hours.
Midazolam works by increasing the effects of a brain chemical called GABA. GABA helps people feel calm and sleepy, which is why the drug is useful before surgery. But this calming effect may also interfere with the signals that keep PER2 active.
In simple terms, the drug’s helpful effects during the day may become risky at night because it weakens the heart’s defense system when it’s already running at lower strength.
This research, led by Dr. Tobias Eckle and published in the journal Frontiers in Cardiovascular Medicine, shows how deeply connected our biology is to the timing of treatments. It also suggests that medicine isn’t always “one size fits all”—especially when time of day can make such a big difference.
This idea is not completely new. Doctors already know that some blood pressure medicines work better when taken at night. But this study adds more evidence that the concept of “chronomedicine”—matching treatment to the body’s natural clock—could improve many other types of care.
For doctors and hospitals, this could lead to changes in how surgeries and medications are scheduled. If midazolam is safer when given during the day, for example, it may make sense to avoid non-urgent surgeries at night whenever possible.
For patients, it’s a reminder of how complex the human body is—and how even small details like timing can play a big role in health outcomes. Understanding and respecting our body’s natural rhythms could be a key step in making medical treatments safer and more effective in the future.
If you care about health, please read studies about the benefits of low-dose lithium supplements, and what we know about egg intake and heart disease.
For more health information, please see recent studies about potatoes and high blood pressure, and results showing 6 best breads for people with heart disease.
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