An Oxford University researcher has found evidence that working before 10 a.m. makes employees ill, stresses them out, and is overall bad for business.

Dr. Paul Kelly, a researcher at Oxford University has found through his work that employees working before 10 a.m. that are under 55 years of age has posed a “serious threat” to performance, mood and mental health.

The studies were performed on people of all ages through circadian rhythms and they have shown that the average 10-year-old will not fully focus on academic work before 8.30 a.m. and a 16-year-old should start academic work at 10 a.m. for best results and university students should start at 11 a.m. He also suggests that changing times of school and work for young adults could improve their scores by 10 percent.

Cr. Paul Kelly was once head teacher in Tyneside where he changed the school start time from 8:30 a.m. to 10 a.m. and students top grades rose by 19%.