Multiple Olympians have posted on TikTok sharing that their beds are “rock solid,” which could affect their ability to perform their best, experts say.

Many of the athletes competing in the 2024 Paris Olympics have been staying in the Olympic Village, which provides them with cardboard beds for their stay.

The beds are made by Japanese mattress manufacturer Airweave and the frames are indeed made of cardboard, to make them easier to recycle at the end of the Games, according to Olympics organizers.

But quite a few Olympics have posted on social media that they’re struggling to sleep on the beds because they’re uncomfortable — this includes Team USA’s Simone Biles, who competed Sunday in the women’s gymnastics team qualifiers.

In a reply to a TikTok, she wrote: “the beds sucks … BUT we are getting mattress toppers so hopefully it’ll get better.”

The beds in the Olympic Village made headlines in 2021 for being made from cardboard, a decision that was rumored at the time to prevent Olympians from having sex. The truth, according to the Olympics X account, is that the beds were made to be recyclable and make the Games more environmentally friendly.

Here’s what to know about the cardboard beds at the Olympic Village and how they may affect athletes’ performance.

What are the beds like at the 2024 Olympics?

This year, the beds are once again made of cardboard in an effort to promote sustainability and will be recycled in France after the games, according to a video on the Olympics YouTube account.

The mattresses are each made up of three modules and can be extended based on the height of the athlete.

But the reviews about the comfort of the beds have been mixed.

Olympians say their cardboard beds are uncomfortable

Aleah Finnegan, a gymnast representing the Philippines, shared a TikTok of herself trying out her bed.

“First, it’s not very soft,” she laughed as she sat down on the mattress. “But we went into the village and we had this (artificial intelligence) bed analysis.”

The mattresses, made by Airweave, are made to have different degrees of firmness on each side — for example, moderate on one side and extra firm on another.

Finnegan then showed how her bed has a thin mattress topper and then the mattress itself, which she said “looks like hot glue.”

“They’re not that comfortable,” she ended the clip.

Another Olympian, Australian water polo player Tilly Kearns, called the mattress “rock hard” in a TikTok. Kearns’ roommate also declared her “back is about to fall off” after sleeping on it for a night.

Kearns then explained that she tried sleeping on the softer side, but it still was too hard.

In an update, Kearns revealed her team manager got her and her teammates a thick mattress topper, adding that she was “so grateful” because she was “waking up every second hour. … I actually thought about going on the floor. I thought about it, I didn’t do it.”

Thanks to the mattress topper, “you’ll be expecting some gold medal performances from here on out from Team Australia,” she quipped.

Biles also shared on TikTok that the beds “suck” and that she was trying to get a mattress topper.

Olympics committees and manufacturer respond to criticism of cardboard beds

Asked how comfortable the mattresses are and how that may affect performance of the Olympians, an Airweave spokesperson tells TODAY.com: “Airweave differs from traditional mattresses by containing no springs or foam — we’ve collaborated with sleep experts and athletes to optimize the performance-enhancing benefits of sleeping on an airweave mattress.”

“We encourage all athletes to join us at the Mattress Fitting Center in Athletes Village for a personalized consultation, which uses our AI-based MattressFit app to analyze and recommend the best configuration for their body type/needs. We’ve had the pleasure of positively connecting with hundreds of athletes in Paris already and aim to meet hundreds more.”

“Not only are airweave mattresses unique because they’re fully customizable, the science-backed interwoven design also ensures a firmer sleeping surface that maintains ideal sleeping posture, effortless turning, better distribution of weight, and optimal breathability for longer periods of quality sleep.”

The Organizing Committee for the Olympic Games tells TODAY.com in an email statement: “The choice of these beds for the Olympic and Paralympic Village is primarily linked to our ambition to ensure minimal environmental impact and a second life for all equipment used during the short period of the Games. The quality of the furniture has been rigorously tested to ensure it is robust, comfortable, and appropriate for all the athletes who will use it, and who span a very broad range of body types. Also, Airweaves’ offer is not standardized, and each athlete can choose the firmness of their mattresses, as well as customize them to their morphology.”

The International Olympics Committee (IOC) referred TODAY.com to the Paris organizing committee for comment.

How an uncomfortable bed can affect Olympians’ performance

Sleeping on an uncomfortable mattress can negatively affect an elite athlete to the point where they may even forgo a medal they might’ve otherwise won, Dr. Chris Winter, a sleep specialist and neurologist who researches sleep and athletic performance, tells TODAY.com.

“It’s sort of like (asking) the question: If we kept all the athletes awake all night long and didn’t allow them to sleep, would that affect their performance?”

“The bed is foundational to your sleep at night,” Winter explains. “Beds provide a certain degree of support, temperature regulation, and the comfort and any of those things that are distracting to the athlete who’s already traveling a great distance, dealing with jet lag — there’s no end to the number of problems that could cause.”

An uncomfortable mattress is most likely to reduce deep sleep, which “has everything to do with our maximal performance,” Winter says. “It has implications in terms of recovery, so your ability to swim a preliminary and come back the next day and swim in the finals.”

He also points out that knowing your bed is uncomfortable, given the heightened stress of the Olympics, can also be “psychologically damaging. The athlete starts to believe, ‘Oh, I’m sleeping so poorly. It’s loud in the Olympic Village, and my roommate snores, and this bed is so uncomfortable, and it’s hot.'”

“When the athlete starts to believe that those things are impairing their ability to perform, all of those negatives can be incredibly compounded,” Winter adds.

But it’s not an all-or-nothing issue. Sleep quality is a spectrum, and there are steps the athletes can take to make sure they’re getting better sleep — and a good mattress topper is one of them, he says.

He also recommends they bring their own pillow and anything else from your home that can help you re-create the sleep routine you’re used to.