diff --git a/http-client/Network/HTTP/Client.hs b/http-client/Network/HTTP/Client.hs
index e6a3c7a5..4182ee58 100644
--- a/http-client/Network/HTTP/Client.hs
+++ b/http-client/Network/HTTP/Client.hs
@@ -323,14 +323,14 @@ managerSetProxy :: ProxyOverride -> ManagerSettings -> ManagerSettings
 managerSetProxy po = managerSetInsecureProxy po . managerSetSecureProxy po
 
 -- @since 0.7.17
-managerSetMaxHeaderLength :: Int -> ManagerSettings -> ManagerSettings
+managerSetMaxHeaderLength :: Word -> ManagerSettings -> ManagerSettings
 managerSetMaxHeaderLength l manager = manager
     { managerMaxHeaderLength = MaxHeaderLength l }
 
 -- @since 0.7.18
-managerSetMaxNumberHeaders :: Int -> ManagerSettings -> ManagerSettings
-managerSetMaxNumberHeaders l manager = manager
-    { managerMaxNumberHeaders = MaxNumberHeaders l }
+managerSetMaxNumberHeaders :: Word -> ManagerSettings -> ManagerSettings
+managerSetMaxNumberHeaders n manager = manager
+    { managerMaxNumberHeaders = MaxNumberHeaders n }
 
 -- $example1
 -- = Example Usage
diff --git a/http-client/Network/HTTP/Client/Connection.hs b/http-client/Network/HTTP/Client/Connection.hs
index e846f3ee..99a3502e 100644
--- a/http-client/Network/HTTP/Client/Connection.hs
+++ b/http-client/Network/HTTP/Client/Connection.hs
@@ -50,12 +50,12 @@ connectionReadLineWith mhl conn bs0 =
     go bs front total =
         case S.break (== charLF) bs of
             (_, "") -> do
-                when (total >= unMaxHeaderLength mhl) $ do
+                when (total >= unMaxHeaderLength mhl && total /= 0) $ do
                     -- We reached the maximum length for an header field.
                     throwHttp OverlongHeaders
                 bs' <- connectionRead conn
                 when (S.null bs') $ throwHttp IncompleteHeaders
-                go bs' (front . (bs:)) (total + S.length bs)
+                go bs' (front . (bs:)) (total + fromIntegral (S.length bs))
             (x, S.drop 1 -> y) -> do
                 unless (S.null y) $! connectionUnread conn y
                 return $! killCR $! S.concat $! front [x]
diff --git a/http-client/Network/HTTP/Client/Headers.hs b/http-client/Network/HTTP/Client/Headers.hs
index 7bb8012a..82badf87 100644
--- a/http-client/Network/HTTP/Client/Headers.hs
+++ b/http-client/Network/HTTP/Client/Headers.hs
@@ -91,13 +91,13 @@ parseStatusHeaders mhl mnh conn timeout' onEarlyHintHeaders cont
             Just (i, "") -> Just i
             _ -> Nothing
 
-    guardMaxNumberHeaders :: Int -> IO ()
+    guardMaxNumberHeaders :: Word -> IO ()
     guardMaxNumberHeaders count =
-        when (count >= unMaxNumberHeaders mnh) $ do
+        when (count >= unMaxNumberHeaders mnh && count /= 0) $ do
             -- We reached the maximum number of header fields.
             throwHttp OverlongHeaders
 
-    parseHeaders :: Int -> ([Header] -> [Header]) -> IO [Header]
+    parseHeaders :: Word -> ([Header] -> [Header]) -> IO [Header]
     parseHeaders count front = do
         guardMaxNumberHeaders count
         line <- connectionReadLine mhl conn
@@ -112,7 +112,7 @@ parseStatusHeaders mhl mnh conn timeout' onEarlyHintHeaders cont
                         -- an exception, ignore it for robustness.
                         parseHeaders count front
 
-    parseEarlyHintHeadersUntilFailure :: Int -> ([Header] -> [Header]) -> IO [Header]
+    parseEarlyHintHeadersUntilFailure :: Word -> ([Header] -> [Header]) -> IO [Header]
     parseEarlyHintHeadersUntilFailure count front = do
         guardMaxNumberHeaders count
         line <- connectionReadLine mhl conn
diff --git a/http-client/Network/HTTP/Client/Types.hs b/http-client/Network/HTTP/Client/Types.hs
index 71077975..7b740a41 100644
--- a/http-client/Network/HTTP/Client/Types.hs
+++ b/http-client/Network/HTTP/Client/Types.hs
@@ -826,14 +826,14 @@ data ManagerSettings = ManagerSettings
     -- Since 0.4.7
     , managerMaxHeaderLength :: MaxHeaderLength
     -- ^ Configure the maximum size, in bytes, of an HTTP header field.
-    -- Set it to a negative number to remove this limit  (eg: for debugging purposes).
+    -- Set it to 0 to remove this limit  (eg: for debugging purposes).
     --
     -- Default: 4096
     --
     -- @since 0.7.17
     , managerMaxNumberHeaders :: MaxNumberHeaders
     -- ^ Configure the maximum number of HTTP header fields.
-    -- Set it to a negative number to remove this limit  (eg: for debugging purposes).
+    -- Set it to 0 to remove this limit  (eg: for debugging purposes).
     --
     -- Default: 100
     --
@@ -922,20 +922,20 @@ data StreamFileStatus = StreamFileStatus
 --
 -- @since 0.7.14
 newtype MaxHeaderLength = MaxHeaderLength
-    { unMaxHeaderLength :: Int
+    { unMaxHeaderLength :: Word
     }
     deriving (Eq, Show, Ord, Num, T.Typeable)
 
 noMaxHeaderLength :: MaxHeaderLength
-noMaxHeaderLength = - 1
+noMaxHeaderLength = 0
 
 -- | The maximum number of header fields.
 --
 -- @since 0.7.18
 newtype MaxNumberHeaders = MaxNumberHeaders
-    { unMaxNumberHeaders :: Int
+    { unMaxNumberHeaders :: Word
     }
     deriving (Eq, Show, Ord, Num, T.Typeable)
 
 noMaxNumberHeaders :: MaxNumberHeaders
-noMaxNumberHeaders = - 1
+noMaxNumberHeaders = 0