Your body hates Mondays more than you do, new study finds

Hate Mondays? Turns out your body does, too.

A new study from the University of Hong Kong found that older adults who felt anxious on Mondays had 23% higher levels of stress hormone cortisol in their body up to two months later, compared to those who reported anxiety on other days.

And that Monday-specific stress could be quietly damaging your health — no matter your age, job status or daily routine, experts said.

The study, published in the Journal of Affective Disorders, analyzed data from more than 3,500 adults over age 50 in England. Participants first reported how anxious they felt and what day of the week it occurred. One to two months later, researchers collected hair samples to measure cortisol — a marker of how much stress had accumulated over time.

Cortisol helps humans stay alert and respond to threats — but when it stays high for too long, it can weaken the immune system and raise the risk of heart disease, anxiety and other chronic problems.

Monday anxiety was the only day linked to a lasting cortisol spike likely because the day carries a sense of “uncertainty, danger or dread,” said Modupe Akinola, a professor at Columbia Business School who studies stress and performance.

This effect showed up even in retirees, a sign that years of Monday stress may leave a lasting imprint on the brain and body.

The stress response is partly psychological — driven by our expectations — but shifts in sleep, eating and activity on weekends can also throw off the body’s internal clock, making Monday morning feel even worse, Robert Sapolsky, a biologist and neuroscientist at Stanford University who studies stress, told The Post.

“Cortisol is not just reactive — a lot of what it does is anticipatory,” said Sapolsky, author of “Why Zebras Don’t Get Ulcers.” “Expectation of stress can drive cortisol levels even higher than the stress itself.”

The jolt from weekend to weekday responsibilities makes Mondays feel harder, noted Akinola.

“There is something effortful about Mondays — you have to get up, get dressed, get focused, deal with traffic, when over the weekend you typically don’t deal with these things,” Akinola said. “All of those extra demands that come on Monday make it feel like you may not have the resources to cope … and your body’s stress system is telling you to get ready to battle.”

That stress buildup may help explain why heart attacks are more common on Mondays — a pattern documented in previous studies linking the start of the week to increased cardiovascular risk.

This repeated psychological strain, especially the kind built into our daily routines, can gradually wear down the body and leave it more vulnerable to long-term health risks, Sapolsky said.

Akinola recommends a weekly “stress inventory” — spotting what you’re dreading before your body kicks into fight-or-flight mode.

“People typically don’t even realize they are stressed, let alone have clarity on what is stressing them out and how their body might respond,” Akinola said. “A daily or weekly stress inventory … will help stress move from being background noise to top of mind and when this happens, you can actually take control.”