at a stretch

Without a break or interruption. The phrase is usually preceded by a length of time. I can only drive five hours at a stretch, so you'll have to take over soon.

continuously; without stopping. We all had to do eight hours of duty at a stretch. The baby doesn't sleep for more than three hours at a stretch.

continuously on end Sometimes I work for ten hours at a stretch. I can't concentrate for more than 15 minutes at a stretch.

Also, at one stretch. At one time, during one period. For example, Working quickly, she hoped to finish all the drawings at a stretch. In contrast to the nearly synonymous at a sitting, this idiom, first recorded in 1774, does not imply being seated while engaging in a single continuous activity. Rather, it transfers the meaning of stretch as "a continuous length" to "a continuous time period."