(NYTIMES) - Since Mr John Jannuzzi began drinking water last month from a bulky bottle with a protruding plastic straw, he has taken measures to keep the mammoth contraption out of Zoom's view.

"I feel like a total baby," said the 35-year-old founder of Jannuzzi's Cookies. "I'm basically drinking from an adult sippy cup."

The bottle he drinks from, all day long, is adorned by time stamps and aspirational messages ("11am - Remember your goal"; "1pm - Keep chugging" and "7pm - Almost finished" among them) to get him drinking more water than he likely needs or certainly thirsts for.

It has a sturdy plastic handle with built-in finger grooves which allow you to get a firm grasp, like a barbell.

Mr Jannuzzi, who lives in Brooklyn, noticed people on Instagram posting photos of their motivational water bottles and chatted with a few people who said better hydration led to improvements in complexion and energy.

This got him thinking about his own drinking habits: He guzzles water during and after his morning workouts, but had not been taking in much liquid in the hours after, aside from his nightly tequila on the rocks.

So he spent about US$40 (S$53) for two almost-2-litre water bottles, one for himself and one for his girlfriend, Ms Alex Rush, also 35.

"When you open the box from Amazon and first see it, you're like, 'This thing is huge, you've got to be kidding me'," he said. "But after a week of drinking close to 3.8 litres a day, my mood is better and I feel clearer."

His ho-hum work-from-home days are now imbued with the novelty of binge water-drinking and frequent trips to the bathroom.

"We have been inside for a year," he said. "At this point, we'll take what we can get when it comes to something new."

This is a big moment for the "motivational hydration industry", said Mr Jason Holloway, 31, an entrepreneur in Fort Lauderdale, Florida, who, with Mr Matthew Hernstadt, 32, started a company called HydroMate in 2019.

Back then, Mr Holloway saw himself an H2O guy living in a soda-pop world.

He wanted to help inspire people to drink more water; to motivate them to sip all day long. The idea, he said, was "to create a bottle that turns the drinking of water, and the dread of drinking water, into a fun drinking game that you play throughout the day".

With time markings that are meant to keep drinkers on track to meet their goal and accompanying messages - like "You've got it" (10am) and "No excuses" (4pm) - HydroMate bottles come in 3.8-litre, 1.9-litre and 0.9-litre sizes, in an array of colours, ranging in price from US$19 to US$23.

They can be slung over the shoulder with luggage straps for on-the-go slurping.

Mr Holloway said: "I've heard it from so many customers, 'This bottle is so huge and I don't know how I'm going to do it. It's noon and I'm only at 10 o'clock. But the little friendly reminders really motivate you."

He says his company has sold hundreds of thousands of bottles.

New Orleans-based Danielle Prescod, 32, a founder of the diversity, equity and inclusion firm 2BG, loves the motivational 1.9-litre water bottle she bought from Amazon so much that she has become something of an Instagram water-drinking influencer.

Last month, she began to realise how much her water consumption had diminished now that she no longer works in an office.

Pre-pandemic, she said, "I would walk out of my office, fill up my water bottle and go to the bathroom several times a day.

"But at home, I noticed I was drinking less water because I was less active, there was no real meal time. The whole concept of time and ritual had changed."

She said encouraging this habit helps distract from the bad news and political vitriol that has characterised the past year.

"I think the reason it's catching on so much is because it's a healthy thing. Drinking water cannot be bad, it cannot be controversial in any way shape or form," she said.

Carrying a particular water bottle has signified cultural cachet in America for three decades, said Ms Anita Rose, a writer in Virginia who is an amateur historian dedicated to 1990s arcana and who sees bottled water and water bottles as pop-culture totems.

From Evian bottles littered around Shelley Long in the 1989 film Troop Beverly Hills to the Naya bottle tucked in the golden carrier of Alicia Silverstone's character Cher in 1995's Clueless to the Hydro Flasks favoured by today's VSCO Girls, "keeping a bottle of water in hand makes it look like you're healthy and it became a status symbol", said Ms Rose, 37.

The idea that a person should drink eight glasses of water a day (about 1.9 litres) comes from nutritional recommendations issued more than 70 years ago, said professor of paediatrics Aaron Carroll at Indiana University School of Medicine, who has written about health myths. Those recommendations accounted for water ingested from other sources like fruit, vegetables, coffee and even beer.

But drinking an additional 3.8 litres of water every day, or even almost 2 litres, is neither necessary nor harmful for most people, he said.

"For the vast majority of people, it's not a terrible idea to drink 2 litres a day," he said, especially if the water ends up replacing sugary beverages like soda. "But the idea that you have to do it is somewhat strange and the main result will be that you end up peeing more."

There are more economical ways of motivating your hydration than buying a bottle from Amazon.

In August, fitness and wellness coach Vandie Barnard in Woodbridge, Virginia, wanted to increase his water intake.

His wife, Ms Lakisha Barnard, 32, suggested that they make their own version of water bottles she had seen on social media.

They went to the supermarket and bought huge plastic bottles of water and wrote encouraging quotes like "Start great" and "Be greater" with a Sharpie pen on the bottles. They guzzled and refilled daily.

This helped them to get into the ritual of drinking 3.8 litres a day. Now, Mr Barnard is teaching his clients to adopt the practice too.