Leicester City January signing Harry Souttar has admitted the Premier League is a significant challenge.
Arriving in January from Stoke City, Souttar was expecting a baptism of fire after moving up a division.
He has not been proven wrong, as he admits that there is no time to rest on your laurels in the Premier League.
"The concentration has been the biggest difference for me," Souttar said to Australian media.
"The physio said to me after the first week, 'your heart rate has gone a bit high this first week'. I said, 'Yeah, I didn't need a heart rate monitor to tell me that'.
"The tempo has obviously stepped up ... there's no rest."