Working mums regularly put in a 28-hour week looking after the kids – on top of their full-time job, according to a survey.
Researchers found caring for the children and managing their home, as well as holding down a paid job, ensure mums are on the go for just over 13 hours every weekday.
Cooking and preparing food, running errands for the family and taking care of pets are daily tasks carried out amid days which begin at 6.45am up until they start work, and then after work until 7.52pm when the kids go to bed, the study found.
It also revealed three quarters of mums rarely get a chance to sit down and eat breakfast or dinner at home because of their hectic schedule.
The workload means that, including a 37-and-a-half hour a week full-time job, millions of mums are putting 66 hours.
But most mums do get a bit of a break at weekends when dad is home to do his share of the housework and help out with the children.
The study of 2,000 mums, commissioned by natural cold remedy Kaloba, found in an average week, more than eight-and-a-half hours is spent entertaining the children, while almost five hours is taken up with cooking and preparing food.
Three hours and 38 minutes is spent on the chores and cleaning the home, with more than two hours spent buying food and groceries each week.
Washing-up or loading the dishwasher accounts for almost two hours per week, while just over one hour and 30 minutes is spent running errands for everyone in the family.
One hour and 27 minutes is taken up with making the beds or tidying bedrooms, another hour and 25 minutes on helping the children with their homework and an hour and 21 minutes ferrying children to school or evening clubs.
An hour and 22 minutes is then spent looking after family pets or walking the dog.
On top of this, 40% of mums hold down a full-time job, adding another 37 hours and 30 minutes to the time they spend on the go each day.
In fact, almost nine in ten mums are so busy they often have days when they are doing something from the moment they wake up until the moment they go to sleep.
And 92% reckon being a mum is a full-time job in itself.
Researchers also found that 63% of mums worry about being so busy that it might be affecting their immune system. More than three quarters also worry that they are more run down due to their hectic lifestyles and more prone to colds and bugs.
And 79% are often picking up colds and bugs from their children or their friends. Three quarters of mums said they dread their children getting colds because they know they will more than likely end up with it too.