Americans reported bizarre physical and mental alignments leading up to and during Monday's solar eclipse.
Called 'eclipse sickness,' the symptoms have included headaches, fatigue, changes in menstrual cycles and insomnia.
While NASA has said there is no evidence linking human health and the solar eclipse, studies have found that the celestial event can impact animals - specifically dogs that may appear anxious.
A total solar eclipse happens when the moon and the sun line up perfectly and the moon is close enough to us to cover the whole of the sun, from our perspective.
The last to appear in the US was in 2017 and the next is set for August 23, 2044.
Americans are being plagued by the 'eclipse sickness,' bizarre physical and mental alignments that appeared leading up to and on the day of the solar eclipse. Symptoms have included headaches, fatigue, changes in menstrual cycles and insomnia
Pictured is the eclipse forming in Arlington, Texas
Eclipse sickness
On Monday, the solar eclipse moved its way up the US starting in Texas and ended in Maine - and people reported strange side effects.
Individuals flocked to social media to share their symptoms and seek comfort that others may be experiencing similar issues.
'Anyone else suffering from weird insomnia, no appetite and other weird sh** that can't be explained,' one user on X shared.
'Someone told me the eclipse might have something to do with it but I don't get how. What the f**k is going on?'
NASA has denied the concept, saying there is no physical relationship between a total solar eclipse and a person's health
Some women have shared that their menstrual cycle synced with April 8's event, but there is no scientific evidence to support there is a connection
On Monday, the solar eclipse will move its way up the US starting with Texas and ending in Maine - and people have already reported strange side effects
Others have said that they felt mentally off in the last few days leading up to Monday.
'Anyone feeling emotional with the upcoming solar eclipse,' reads a post on X from MC Phoenix.
'Doctors call it "eclipse sickness." People with mental illness may be especially sensitive during this time.'
Some women shared that their menstrual cycle synced with April 8's event, but there is no scientific evidence to support there is a connection.
The Healthcare Communication Network has noted that such changes and 'weird feelings' could be attributed to psychological factors, 'such as excitement, anxiety, and the influence of social cues, may explain the physical and emotional responses some individuals attribute to eclipse sickness,' reads the website.
Leann Poston, MD, a physician-writer and researcher at Invigor Medical, told MDLinx that while she has not seen a link between the eclipse and changes in physiology and disease, she notes that 'when an event occurs that is outside the norm and it feels difficult to explain, it can cause an increase in cortisol, which can have physical and psychological effects.'
When humans observe such an event, they may feel excited that causes a spike in epinephrine and norepinephrine - hormones that play a role in your body's fight-or-flight response.
'[This increases] heart rate, blood pressure, breathing rate, and blood flow to muscles,' said Poston.
'Cortisol also increases glucose release into the bloodstream so the body is ready for 'fight or flight.'
NASA also noted that they only physical concern during a total solar eclipse is your eyes - noting that people should not look directly at the sun.
That is because it can cause retinal damage.
But experts have warned that pets could experience unusual behaviors when the moon completely blocks out the sun - the event can make dogs anxious
'You can view the eclipse directly without proper eye protection only when the moon completely obscures the sun's bright face—during the brief and spectacular period known as totality,' the American space agency shared.
Crazed pets
But it is not just humans who appear to be impacted - pets have also shown abnormal behaviors.
Your dog might also respond to the eclipse by showing signs of anxiety like pacing, scratching and howling - similar to how they react to a thunderstorm or firework display.
The full reason why animals exhibit unusual behaviors during solar eclipses still is not fully understood, but scientists have theorized pets react to the natural light dimming and drop in temperature as the sun is blocked by the moon.
A total solar eclipse happens when the moon and the sun line up perfectly and the moon is close enough to us to cover the whole of the sun, from our perspective
The solar eclipse could be disrupting animals' circadian rhythm - the 24-hour biological clock telling humans or animals that it's time to wake up or time for bed.
That could also explain why some people may feel fatigued on Monday after seeing the event.
Denis Shull posted on X: 'Wondering if anyone else's dog is acting very odd this morning? One of ours is doing things he never ever does... but he doesn't seem sick. Is this some sort of pre-eclipse thing? (I know... that's weird but ???)'
Cell phone disruptions
Millions of tourists are expected to flock to the path of totality during the solar eclipse on April 8 - and experts warn the influx could disrupt cellular activity.
To ease the burden on many American cities, T-Mobile is deploying additional cell sites that will be on standby in areas expecting high tourist traffic.
Rebecca Owens, director of the Richland County Emergency Management Authority (EMA), told the Richland Source: 'Cell phone (reception) will be very, very sketchy.
'There will be lots of issues with connectivity and that type of thing.'
A T-Mobile spokesperson told DailyMail.com: 'T-Mobile’s network is ready for the eclipse. Our emergency teams are working with state and local officials across the country to provide additional support where needed for large gatherings.'
Arkansas is along the path of totality, where state officials are preparing for the tourist boom that could see the current three million population double in size.
NASA also noted that they only physical concern during a total solar eclipse is your eyes - noting that people should not look directly at the sun
Rep. Davis Whitaker, from Fayetteville, said during a legislative meeting in December: 'I'm concerned about cellular communication.
'Are the cellular providers in the state part of this plan?'
Up north in Maine, Franklin County is also holding discussions to prepare for limited or even no smartphone service where tens of thousands of visitors are expected, worrying that 'cell coverage is scarce as it is.'
Franklin County Emergency Services Coordinator Rob Demarse told Adirondack Daily Enterprise that the town is working with the Department of Homeland Security to map all roads for cell coverage.
And in Texas, which is set to see more than one million out-of-towners, officials are advising people to enable Wi-Fi calling in the event of service interruptions.
More fatal car crashes
Researchers at the University of Toronto analyzed road traffic data from the 2017 solar eclipse and found there were more than 1,000 additional road deaths across the US three days before and after the cosmic event.
The average car deaths in the US each day is around 114, but there were at least 189 each day during the week of the solar eclipse four years ago.
The overall increased traffic risk was comparable to those observed on major holidays including Thanksgiving, Memorial Day, and the 4th of July weekend
The reason for the increase in driving is due to millions of more people being on roads as they leave their hometown and head off to cities within the path of totality.
According to the report, the overall increased traffic risk was comparable to those observed on major holidays including Thanksgiving, Memorial Day, and the 4th of July weekend.
In the hour leading up to the event, the number of crashes rose above average but dropped to below average during the eclipse and then shot up to a shocking 50 percent above average afterward.