If you’ve been finding it particularly tough to bounce back after a night out, it could be more than just an aggressive reminder that you’re getting older.

According to a report published in medical journal Cureus, there’s a possible link between worsening hangovers and Post-Acute COVID-19 Syndrome (PACS), a.k.a. Long COVID. The article documents a case series of four patients between ages 36 and 60 at Stanford University’s PACS Clinic. According to the report, all four patients had a confirmed history of COVID-19 infection and persistent symptoms that lasted longer than four weeks. While being evaluated for consistent symptoms linked to COVID-19, the patients all claimed to have experienced increased alcohol sensitivity since their diagnoses.

The post-drinking symptoms patients described all line up with typical hangover woes, such as headaches, fatigue, and impaired focus. The oldest patient, a 60-year-old man, claimed to drink “twice a month with no issues or reactions” prior to his diagnosis, but now can’t consume alcohol without experiencing “chronic, daily headaches characterized by a squeezing sensation at the top and back of the head.” A head CT scan and brain MRI showed no physical changes following his COVID diagnosis.

A 40-year-old female patient from the study has dealt with similar issues: before her initial COVID infection, she could “easily tolerate about seven mixed drinks containing hard liquor in one night,” but now feels like she gets “alcohol poisoning” even after ingesting small amounts of booze.

The report considers that increased neuroinflammation from PACS could “lead to reduced integrity of the blood-brain barrier, thus increasing sensitivities to not only alcohol but potentially other substances.” Although the patients’ claims are substantial, they were self-reported, so more research is needed to confirm the connection between alleged bad hangovers and PACS.

In the meantime, if you’re not feeling so hot after a night of heavy imbibing, it might be best to pass on those Bloody Marys and Mimosas.