Ten employees at Kidsunlimited, based at Cambridge Science Park, took part in the 10-and-a-half hour challenge from 7.30am to 6pm on Friday.
Manager Lisa Gibbs, 29, said: “We cycled and rowed all day and we took it in half-hour shifts to do each. By the end of it I had done two hours of rowing and two hours of cycling.
“It was an amazing experience and the children loved to see what was going on and asked what charity was, which we explained to them.”
Despite the 10 volunteers being weary and saddle-sore by the end of the challenge, they were delighted that they had managed to raise about £500 for the Blue Smile charity.
Miss Gibbs said: “We hope to have raised £500 when it is all collected in. It is going to our charity of the year, Blue Smile, which is a local charity set up by one of our mums from another of our nurseries. It supports children who have had a hard start in life.”
By the end of the event they had jointly travelled 85 miles on the exercise bike and 42 miles on the rowing machine.