diff --git a/README.md b/README.md
index 9f88452..5534ff2 100644
--- a/README.md
+++ b/README.md
@@ -47,7 +47,7 @@ $ docker run --rm -d --name stress-tests --privileged -v /dev:/dev -v /tmp:/tmp
 Check if the stress tests started successfully:
 
 ```
-$ docker logs stress-tests 
+$ docker logs stress-tests
 Setting up stress tests...
 RT stress tests started successfully!
 ```
@@ -61,7 +61,11 @@ Run the following command to execute the `rt-tests` container and start measurin
 $ docker run --rm -it --name rt-tests --cap-add=sys_nice --cap-add=ipc_lock --cap-add=sys_rawio --ulimit rtprio=99 --device-cgroup-rule='c 10:* rmw' -v /dev:/dev -v /tmp:/tmp torizon/rt-tests:$CT_TAG_RT_TESTS
 ```
 
-The tests will run for at most 12 hours, but can be interrupted at any time by pressing CTRL-C.
+The tests will run for at most 12 hours, but can be interrupted at any time by
+pressing CTRL-C. You can specify a different length of the test run in seconds
+by passing the environment variable *DURATION* to the container (with
+`-e DURATION=…`); for other units append `m` for minutes, `h` for hours and `d`
+for days.
 
 After the tests are finished, stop the `stress-tests` container:
 
@@ -111,4 +115,4 @@ So if you want to run the `rt-tests` container on a non-PREEMPT_RT version of To
 ```
 sudo sh -c "echo 950000 > /sys/fs/cgroup/cpu,cpuacct/docker/cpu.rt_runtime_us"
 docker run --rm -it --name rt-tests --cpu-rt-runtime=950000 --cap-add=sys_nice --cap-add=ipc_lock --cap-add=sys_rawio --ulimit rtprio=99 --device-cgroup-rule='c 10:* rmw' -v /dev:/dev -v /tmp:/tmp torizon/rt-tests:$CT_TAG_RT_TESTS
-```
\ No newline at end of file
+```
diff --git a/rt-tests/rt-tests.sh b/rt-tests/rt-tests.sh
index 305a223..9aabce8 100755
--- a/rt-tests/rt-tests.sh
+++ b/rt-tests/rt-tests.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 
 # Run cyclictest
-if ! cyclictest -S -p99 -i1000 -m -D12h -h400 -q >output; then
+if ! cyclictest -S -p99 -i1000 -m -D${DURATION:-12h} -h400 -q >output; then
   echo "ERROR: cyclictest failed" >&2
   exit 1
 fi