diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9c09183b198..051a223a1a6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -66,6 +66,8 @@ release.
   ([#2290](https://github.com/open-telemetry/opentelemetry-specification/pull/2290))
 - Add semantic conventions for [CloudEvents](https://cloudevents.io).
   ([#1978](https://github.com/open-telemetry/opentelemetry-specification/pull/1978))
+- Change `http.server.active_requests` from asynchronous to synchronous UpDownCounter
+  ([#2451](https://github.com/open-telemetry/opentelemetry-specification/pull/2451))
 
 ### Compatibility
 
diff --git a/specification/metrics/semantic_conventions/http-metrics.md b/specification/metrics/semantic_conventions/http-metrics.md
index 204ef410ab0..e39094e2500 100644
--- a/specification/metrics/semantic_conventions/http-metrics.md
+++ b/specification/metrics/semantic_conventions/http-metrics.md
@@ -17,10 +17,10 @@ type and units.
 
 Below is a table of HTTP server metric instruments.
 
-| Name                          | Instrument                 | Unit         | Unit ([UCUM](README.md#instrument-units)) | Description |
-|-------------------------------|----------------------------|--------------|-------------------------------------------|-------------|
-| `http.server.duration`        | Histogram                  | milliseconds | `ms`                                      | measures the duration of the inbound HTTP request |
-| `http.server.active_requests` | Asynchronous UpDownCounter | requests     | `{requests}`                              | measures the number of concurrent HTTP requests that are currently in-flight |
+| Name                          | Instrument    | Unit         | Unit ([UCUM](README.md#instrument-units)) | Description |
+|-------------------------------|---------------|--------------|-------------------------------------------|-------------|
+| `http.server.duration`        | Histogram     | milliseconds | `ms`                                      | measures the duration of the inbound HTTP request |
+| `http.server.active_requests` | UpDownCounter | requests     | `{requests}`                              | measures the number of concurrent HTTP requests that are currently in-flight |
 
 ### HTTP Client