diff --git a/compiler/testdata/goroutine-cortex-m-qemu.ll b/compiler/testdata/goroutine-cortex-m-qemu.ll
index a00d49be..a98592c1 100644
--- a/compiler/testdata/goroutine-cortex-m-qemu.ll
+++ b/compiler/testdata/goroutine-cortex-m-qemu.ll
@@ -5,7 +5,7 @@ target triple = "armv7m-none-eabi"
 
 %runtime.channel = type { i32, i32, i8, %runtime.channelBlockedList*, i32, i32, i32, i8* }
 %runtime.channelBlockedList = type { %runtime.channelBlockedList*, %"internal/task.Task"*, %runtime.chanSelectState*, { %runtime.channelBlockedList*, i32, i32 } }
-%"internal/task.Task" = type { %"internal/task.Task"*, i8*, i32, %"internal/task.state" }
+%"internal/task.Task" = type { %"internal/task.Task"*, i8*, i64, %"internal/task.state" }
 %"internal/task.state" = type { i32, i32* }
 %runtime.chanSelectState = type { %runtime.channel*, i8* }
 
diff --git a/compiler/testdata/goroutine-wasm.ll b/compiler/testdata/goroutine-wasm.ll
index 212bd714..1d840e6d 100644
--- a/compiler/testdata/goroutine-wasm.ll
+++ b/compiler/testdata/goroutine-wasm.ll
@@ -6,7 +6,7 @@ target triple = "wasm32--wasi"
 %runtime.funcValueWithSignature = type { i32, i8* }
 %runtime.channel = type { i32, i32, i8, %runtime.channelBlockedList*, i32, i32, i32, i8* }
 %runtime.channelBlockedList = type { %runtime.channelBlockedList*, %"internal/task.Task"*, %runtime.chanSelectState*, { %runtime.channelBlockedList*, i32, i32 } }
-%"internal/task.Task" = type { %"internal/task.Task"*, i8*, i32, %"internal/task.state" }
+%"internal/task.Task" = type { %"internal/task.Task"*, i8*, i64, %"internal/task.state" }
 %"internal/task.state" = type { i8* }
 %runtime.chanSelectState = type { %runtime.channel*, i8* }
 
diff --git a/src/internal/task/task.go b/src/internal/task/task.go
index 489400df..bad501b6 100644
--- a/src/internal/task/task.go
+++ b/src/internal/task/task.go
@@ -13,7 +13,7 @@ type Task struct {
 	Ptr unsafe.Pointer
 
 	// Data is a field which can be used for storing state information.
-	Data uint
+	Data uint64
 
 	// state is the underlying running state of the task.
 	state state
diff --git a/src/runtime/scheduler.go b/src/runtime/scheduler.go
index c5286d33..44b07f75 100644
--- a/src/runtime/scheduler.go
+++ b/src/runtime/scheduler.go
@@ -88,7 +88,7 @@ func addSleepTask(t *task.Task, duration timeUnit) {
 			panic("runtime: addSleepTask: expected next task to be nil")
 		}
 	}
-	t.Data = uint(duration) // TODO: longer durations
+	t.Data = uint64(duration)
 	now := ticks()
 	if sleepQueue == nil {
 		scheduleLog("  -> sleep new queue")