“Bloody khooni Monday kyun aaya khoon choosne…” from Go Goa Gone (2013) perfectly captures our collective hatred for Mondays, the dreaded representative of the workweek. Every week, it rolls around and smacks us with a groggy reality check, just as we’re bidding adieu to the weekend with a heavy heart. Living it up on the weekends, only to be thrust back into the cold embrace of the workweek, can make Mondays feel like an endless, unflinching battle against the forces of exhaustion, leading it to be called “social jet lag.”

Monday mornings mark a significant shift in moods, leading us to think of it as the worst day of the week. The term “social jet lag” was coined in 2006 by German researcher Till Roennenberg, professor of chronobiology at Ludwig-Maximilian University in Munich. It refers to how our bodies try to reconcile with the time zone we were on during the weekend, while our responsibilities remind us that we’re firmly stuck in the weekday.

This happens because we mess up our internal clocks over the weekend — often by attempting to balance our “sleep debts” from the week by oversleeping — causing us to upset our routines, leading to exhaustion on Monday mornings. Oversleeping on weekends isn’t the only culprit, here, though. Surrendering ourselves to the sweet freedom of ungodly late nights and leisurely mornings as we revel in the absence of alarms and work-related stress, abandoning our weekday sleep routine in the process, and morphing into nocturnal creatures can all create the dissonance that is difficult to recover from. Drinking and partying over the weekends can also leave us with a hangover, in addition to a social drain, to contend with on Monday mornings.

“Just like the way traveling from New York to Los Angeles can sometimes wreak havoc on your circadian rhythm (your body’s natural clock), so too can staying up late at the end of a stressful work week and sleeping in on weekend. By staying up late on Friday and Saturday nights and sleeping in both days afterward, you’re essentially forcing your body into a different time zone, ” explains Raj Dasgupta, a sleep specialist at the USC Keck School of Medicine.

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So, while the infamous “Monday blues” is a psychological phenomenon resulting from the the anticipation of returning to work and the pressures associated with it, the misalignment of sleep patterns worsens its mental burden. “Social jetlag promotes practically everything that’s bad in our bodies,” says Roennenberg, adding that “social jetlag and sleep deprivation are practically inseparable.”

Unsurprisingly, then, falling prey to the social jet lag every other week can take a toll on our health. “This pattern of sleeping puts you at risk for the effects of chronic sleep deprivation, which can put you at increased risk for medical conditions such as diabetes and heart disease,” Dasgupta adds. Research further links misaligned sleep schedules to depression, anxiety, chronic illness, weight gain, and reduced cognitive performance.

Explaining why, Sierra Forbush, former research assistant at the University of Arizona College of Medicine — who led a study on social jet lag in 2017 — told The Guardian: “Almost all the hormones in your body are on some sort of circadian rhythm and when you are shifting your sleep time, the entire system is not going to be working as efficiently as it should.”

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Forbush’s study also highlighted the need for regular sleep schedules over simply getting adequate sleep the goal, suggesting that staying up late to work on weekdays, and attempting to catch up on sleep over the weekend, isn’t too helpful. “[W]e found that sleep regularity — beyond sleep duration alone — plays a significant role in our health. This suggests that a regular sleep schedule may be an effective, relatively simple and inexpensive preventative treatment for heart disease, as well as many other health problems,” Forbush added.

As dramatic as this struggle to pry ourselves from the clutches of Monday mornings might sound, the solution to it is rather boring: not letting the weekends seduce us into straying too far from our structured weekday routines. “Instead of waking and sleeping at times that are out of sync with your internal clock and shifting between two different sleep schedules (one for weekdays and one for weekends), try to maintain a healthy and consistent sleep schedule,” Dasgupta recommends.

Experts note that the upsides to maintaining a regular sleep schedule becomes visible rather easily — preventing a sense of behavioral fatigue from setting in and dissuading us from following routine. “While it may feel difficult to keep the same sleeping hours each day, you will likely notice the health benefits right away,” states an article on Very Well Health.