diff --git a/octodns/provider/ns1.py b/octodns/provider/ns1.py
index a910459..8408682 100644
--- a/octodns/provider/ns1.py
+++ b/octodns/provider/ns1.py
@@ -929,7 +929,9 @@ class Ns1Provider(BaseProvider):
         if record.healthcheck_protocol != 'TCP':
             # IF it's HTTP we need to send the request string
             path = record.healthcheck_path
-            host = record.healthcheck_host
+            # if host header is explicitly set to null in the yaml,
+            # just pass the domain (value) as the host header
+            host = record.healthcheck_host or value
             request = r'GET {path} HTTP/1.0\r\nHost: {host}\r\n' \
                 r'User-agent: NS1\r\n\r\n'.format(path=path, host=host)
             ret['config']['send'] = request
diff --git a/octodns/provider/route53.py b/octodns/provider/route53.py
index ad59eb0..0331847 100644
--- a/octodns/provider/route53.py
+++ b/octodns/provider/route53.py
@@ -1131,7 +1131,7 @@ class Route53Provider(BaseProvider):
             'Type': healthcheck_protocol,
         }
         if healthcheck_protocol != 'TCP':
-            config['FullyQualifiedDomainName'] = healthcheck_host
+            config['FullyQualifiedDomainName'] = healthcheck_host or value
             config['ResourcePath'] = healthcheck_path
         if value:
             config['IPAddress'] = value
diff --git a/tests/test_octodns_provider_ns1.py b/tests/test_octodns_provider_ns1.py
index f54c7bd..4ae4757 100644
--- a/tests/test_octodns_provider_ns1.py
+++ b/tests/test_octodns_provider_ns1.py
@@ -757,6 +757,10 @@ class TestNs1ProviderDynamic(TestCase):
         self.assertFalse(monitor['config']['ssl'])
         self.assertEquals('host:unit.tests type:A', monitor['notes'])
 
+        record._octodns['healthcheck']['host'] = None
+        monitor = provider._monitor_gen(record, value)
+        self.assertTrue(r'\nHost: 3.4.5.6\r' in monitor['config']['send'])
+
         record._octodns['healthcheck']['protocol'] = 'HTTPS'
         monitor = provider._monitor_gen(record, value)
         self.assertTrue(monitor['config']['ssl'])
diff --git a/tests/test_octodns_provider_route53.py b/tests/test_octodns_provider_route53.py
index 1e7210d..1bf3332 100644
--- a/tests/test_octodns_provider_route53.py
+++ b/tests/test_octodns_provider_route53.py
@@ -1166,6 +1166,31 @@ class TestRoute53Provider(TestCase):
         })
         stubber.add_response('change_tags_for_resource', {})
 
+        health_check_config = {
+            'EnableSNI': False,
+            'FailureThreshold': 6,
+            'FullyQualifiedDomainName': '4.2.3.4',
+            'IPAddress': '4.2.3.4',
+            'MeasureLatency': True,
+            'Port': 8080,
+            'RequestInterval': 10,
+            'ResourcePath': '/_status',
+            'Type': 'HTTP'
+        }
+        stubber.add_response('create_health_check', {
+            'HealthCheck': {
+                'Id': '43',
+                'CallerReference': self.caller_ref,
+                'HealthCheckConfig': health_check_config,
+                'HealthCheckVersion': 1,
+            },
+            'Location': 'http://url',
+        }, {
+            'CallerReference': ANY,
+            'HealthCheckConfig': health_check_config,
+        })
+        stubber.add_response('change_tags_for_resource', {})
+
         record = Record.new(self.expected, '', {
             'ttl': 61,
             'type': 'A',
@@ -1191,6 +1216,11 @@ class TestRoute53Provider(TestCase):
         # when allowed to create we do
         id = provider.get_health_check_id(record, value, True)
         self.assertEquals('42', id)
+
+        # when allowed to create and when host is None
+        record._octodns['healthcheck']['host'] = None
+        id = provider.get_health_check_id(record, value, True)
+        self.assertEquals('43', id)
         stubber.assert_no_pending_responses()
 
         # A CNAME style healthcheck, without a value