The lesson, hosted by well-known British fitness instructor Joe Wicks and plugged by schools and the media, attracted about 800,000 viewers when he streamed it live on YouTube.
"I'm going to be your PE teacher for the nation which I thought was just going to the UK, but actually has turned out to be so much bigger," Wicks, who has 1.17 million subscribers to his YouTube channel, said at the start of the class which he will run every week day.
With the exception of children of key workers such as medical staff, schools shut their doors for the foreseeable future at the end of last week, leaving parents to look after their children and oversee their education.
"My 11-year-old daughter up in Glasgow just did this and absolutely loved it, thanks so much Joe, she'll see you tomorrow," Andy Downey wrote on Wicks's YouTube page, one of dozens of messages of gratitude.
"My boys absolutely loved this, what a great way to start our mornings, thanks so much," Hannah Stoyles said.However, while the PE video proved a success, other parents reported that some other educational websites that schools were directing pupils to use were crashing because of the extra demand.