diff --git a/sys/ztimer/util.c b/sys/ztimer/util.c
index e8074f6ebf..115af57d40 100644
--- a/sys/ztimer/util.c
+++ b/sys/ztimer/util.c
@@ -55,14 +55,13 @@ void ztimer_sleep(ztimer_clock_t *clock, uint32_t duration)
     mutex_lock(&mutex);
 }
 
-void ztimer_periodic_wakeup(ztimer_clock_t *clock, ztimer_now_t *last_wakeup,
+void ztimer_periodic_wakeup(ztimer_clock_t *clock, uint32_t *last_wakeup,
                             uint32_t period)
 {
     unsigned state = irq_disable();
-    ztimer_now_t now = ztimer_now(clock);
-    ztimer_now_t target = *last_wakeup + period;
-    ztimer_now_t offset = target - now;
-
+    uint32_t now = ztimer_now(clock);
+    uint32_t target = *last_wakeup + period;
+    uint32_t offset = target - now;
     irq_restore(state);
 
     if (offset <= period) {