The stress level of most parents peaks at 8:15am in the middle of the school run, scientists have found.
Chartered psychologist, Dr Simon Moore analysed the saliva of a number of parents at five different intervals in the morning to see how they were coping.
Dr Moore was looking for cortisol, a hormone which is released when the body experiences higher stress levels.
Cortisol levels in parent's saliva were highest as they were dropping their kids off to school at 8:15am.
Some parents even complained of a "stress hangover" from the school run, which lasts until 2:30pm.
A quarter of parents admitted their mood throughout the day was a direct result of how well the school run had gone.
The survey, conducted on behalf of Allianz, found 30% of parents felt getting the kids ready for school could mess up their whole day's schedule, and important meetings could get pushed back.
Over half (55%) of the UK's children travel to school by car, so it was important to have parents relaxed before they got behind the wheel.
The research showed having help with the school run did not necessarily make it less stressful as parents are still against the clock to get their children ready.
However, the parents who took part in the study did feel there were some positives to the school run.
For exampled, 39% said they enjoyed spending time with their children, and a further 36% wanted to hear about their kid's day on the drive home.