March 20, 2026 | Reading time: 5 minutes
Many people struggle with sleep. They lie awake for long periods, don’t sense rested in the morning, drink large amounts of coffee to get through the day and grab melatonin to feel tired. Chronobiologist Satchin Panda from the Salk Institute in California has been studying how modern lifestyles affect our internal clock for years. He researches how the internal clock affects metabolism and sleep and the role intermittent fasting plays in the human body.
The Modern Sleep Crisis: Why Are We So Tired?
Many want to perform at their best during the day. The internal motor runs constantly at high speed, driven by stress and caffeine. Sleep, however, requires the opposite: a conscious slowdown. Just as a mechanic wouldn’t repair a car while the engine is running, we retain our engine running all day and keep our minds awake in the evening with bright light, then expect to simply close our eyes and fall asleep. This expectation is unrealistic. Often, an unfavorable sleep environment contributes as well. It’s rarely truly dark, and frequently too warm.
The Melatonin Paradox: More Isn’t Always Better
Many turn to melatonin for sleep problems. However, we would naturally produce more of the hormone if we were exposed to more daylight during the day. Studies have shown that daylight exposure of about 5000 lux can lead to increased nighttime melatonin production. When people take high doses of melatonin externally, especially in combination with late eating, it can be particularly unfavorable. Melatonin can remain in the body for a long time, sometimes until the next midday, at a level typically associated with the middle of the night. The result is feeling groggy and lethargic. Many then reach for a double espresso to counteract this, followed by melatonin again in the evening, creating a cycle of fighting side effects.
Beyond Sleep: The Broader Impact of Circadian Rhythms
The timing of sleep is also a key consideration. Some believe that sleep before midnight is particularly healthy. However, if someone lives in Berlin but goes to bed at 1 am and gets up at 9 am, they are essentially living in the time zone of Beijing. This isn’t a problem as long as it’s done consistently every day and eight hours of sleep are achieved. This is also what is recommended for shift workers who may come home at midnight and go to sleep around 1 am. They should keep their sleep rhythm constant, even on days off, to minimize disturbances to the circadian system.
Shift workers often see less daylight. It has health benefits to align one’s own daily rhythm more closely with the natural course of the sun, i.e., to get up with sunrise and go to sleep with sunset. However, there are no conclusive comparative studies on this. It would first be necessary to clarify what outcome is being considered: subjective well-being or objective medical parameters. If people live consistently in a stable rhythm, there are generally no problems. Consistent shifts, combined with sufficient good sleep, appear to avoid negative effects.
To the person Satchin Panda is a professor at the Salk Institute in California and one of the world’s leading chronobiologists. He researches how the internal clock affects metabolism and sleep and the role intermittent fasting plays in the human body. Panda is also the author of several books.
Simple Steps for a Better Circadian Rhythm
Drinking a glass of warm water in the morning instead of coffee can assist you wake up. It helps warm up the body, which is a prerequisite for waking up. It also stimulates bowel movements.
Reducing coffee consumption for a period, such as between Thanksgiving and New Year’s, can be beneficial. Without coffee, one may feel tired around 9 pm and sleep seven to eight hours deeply and restoratively.
FAQ
- What is the role of Satchin Panda’s research? He researches how the internal clock affects metabolism and sleep.
- Is melatonin always helpful for sleep? Not necessarily. High doses can disrupt the body’s natural rhythms.
- What is time-restricted eating? It is also referred to as intermittent fasting and is a focus of Panda’s research.
Pro Tip: Prioritize consistent sleep schedules, even on weekends, to strengthen your circadian rhythm.
Want to learn more about optimizing your health through circadian biology? Explore related articles on our site or share your own experiences in the comments below!
