diff --git a/CLAUDE.md b/CLAUDE.md
index 53c996e..2b55c09 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -88,11 +88,11 @@ Mesh v2 uses environment variables for configuration, allowing different setting
 | Variable | Development | Production | Description |
 |----------|-------------|------------|-------------|
 | `MESH_SECRET_KEY` | `dev-secret-key-for-testing` | (set in GitHub Secrets) | Secret key for domain validation |
-| `MESH_HOST_HEARTBEAT_INTERVAL_SECONDS` | `15` | `30` | Host heartbeat interval in seconds |
-| `MESH_HOST_HEARTBEAT_TTL_SECONDS` | `60` | `150` | Host group TTL in seconds (5× interval) |
+| `MESH_HOST_HEARTBEAT_INTERVAL_SECONDS` | `15` | `60` | Host heartbeat interval in seconds |
+| `MESH_HOST_HEARTBEAT_TTL_SECONDS` | `60` | `150` | Host group TTL in seconds |
 | `MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS` | `15` | `120` | Member heartbeat interval in seconds |
-| `MESH_MEMBER_HEARTBEAT_TTL_SECONDS` | `60` | `600` | Member node TTL in seconds (5× interval) |
-| `MESH_MAX_CONNECTION_TIME_MINUTES` | `10` | `50` | Maximum connection time for a group (minutes) |
+| `MESH_MEMBER_HEARTBEAT_TTL_SECONDS` | `60` | `600` | Member node TTL in seconds |
+| `MESH_MAX_CONNECTION_TIME_MINUTES` | `5` | `25` | Maximum connection time for a group (minutes) |
 
 ### Setup for Local Development
 
@@ -118,7 +118,7 @@ npx cdk deploy --context stage=stg
 
 **Command Line Override**:
 ```bash
-MESH_HOST_HEARTBEAT_INTERVAL_SECONDS=30 \
+MESH_HOST_HEARTBEAT_INTERVAL_SECONDS=60 \
 MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS=120 \
 npx cdk deploy --context stage=prod
 ```
diff --git a/docs/api-reference.md b/docs/api-reference.md
index 1348720..1b93510 100644
--- a/docs/api-reference.md
+++ b/docs/api-reference.md
@@ -351,7 +351,7 @@ mutation RenewHeartbeat($groupId: ID!, $domain: String!, $hostId: ID!) {
 
 **重要**: この mutation はホストのみが実行できます。非ホストが実行すると `Unauthorized` エラーが返されます。
 
-**ハートビート間隔**: 環境変数 `MESH_HOST_HEARTBEAT_INTERVAL_SECONDS` で設定（開発環境: 15秒、本番環境: 30秒）
+**ハートビート間隔**: 環境変数 `MESH_HOST_HEARTBEAT_INTERVAL_SECONDS` で設定（開発環境: 15秒、本番環境: 60秒）
 
 ---
 
diff --git a/docs/deployment.md b/docs/deployment.md
index 90336e9..4c8f21c 100644
--- a/docs/deployment.md
+++ b/docs/deployment.md
@@ -74,11 +74,11 @@ cp .env.example .env
 | 変数名 | 開発環境推奨値 | 本番環境推奨値 | 説明 |
 |--------|--------------|--------------|------|
 | `MESH_SECRET_KEY` | `dev-secret-key-for-testing` | （GitHub Secretsで設定） | ドメイン検証用の秘密鍵 |
-| `MESH_HOST_HEARTBEAT_INTERVAL_SECONDS` | `15` | `30` | ホストのハートビート送信間隔（秒） |
+| `MESH_HOST_HEARTBEAT_INTERVAL_SECONDS` | `15` | `60` | ホストのハートビート送信間隔（秒） |
 | `MESH_HOST_HEARTBEAT_TTL_SECONDS` | `60` | `150` | ホストグループの有効期限（秒） |
 | `MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS` | `15` | `120` | メンバーのハートビート送信間隔（秒） |
 | `MESH_MEMBER_HEARTBEAT_TTL_SECONDS` | `60` | `600` | メンバーノードの有効期限（秒） |
-| `MESH_MAX_CONNECTION_TIME_SECONDS` | `300` | `3000` | グループの最大接続時間（秒） |
+| `MESH_MAX_CONNECTION_TIME_SECONDS` | `300` | `1500` | グループの最大接続時間（秒） |
 
 ### 3.3 開発環境用の設定（stg）
 
@@ -101,11 +101,11 @@ MESH_MAX_CONNECTION_TIME_SECONDS=300
 ```bash
 # 本番環境ではGitHub Secretsまたは環境変数で設定
 MESH_SECRET_KEY=<本番用の秘密鍵>
-MESH_HOST_HEARTBEAT_INTERVAL_SECONDS=30
+MESH_HOST_HEARTBEAT_INTERVAL_SECONDS=60
 MESH_HOST_HEARTBEAT_TTL_SECONDS=150
 MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS=120
 MESH_MEMBER_HEARTBEAT_TTL_SECONDS=600
-MESH_MAX_CONNECTION_TIME_SECONDS=3000
+MESH_MAX_CONNECTION_TIME_SECONDS=1500
 ```
 
 **重要**:
@@ -175,10 +175,11 @@ npx cdk deploy
 ```bash
 # 環境変数を直接指定してデプロイ
 MESH_SECRET_KEY="<本番用秘密鍵>" \
-MESH_HOST_HEARTBEAT_INTERVAL_SECONDS=30 \
+MESH_HOST_HEARTBEAT_INTERVAL_SECONDS=60 \
 MESH_HOST_HEARTBEAT_TTL_SECONDS=150 \
 MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS=120 \
 MESH_MEMBER_HEARTBEAT_TTL_SECONDS=600 \
+MESH_MAX_CONNECTION_TIME_SECONDS=1500 \
 npx cdk deploy --context stage=prod
 ```
 
diff --git a/docs/development.md b/docs/development.md
index f5f8555..4c2dace 100644
--- a/docs/development.md
+++ b/docs/development.md
@@ -138,7 +138,7 @@ Mesh v2 は環境変数を使用して設定を管理し、開発環境と本番
 **本番環境（遅い間隔）**:
 - コスト最適化（~70% のコスト削減）
 - メンバーのハートビート 120 秒により、UX を維持しつつ API 呼び出しを削減
-- ホストのハートビート 30 秒により、グループ解散の検出を迅速化
+- ホストのハートビート 60 秒により、グループ解散の検出を迅速化
 - TTL を間隔の 5 倍にすることで、ネットワークの一時的な問題に対応
 
 ### 環境変数の使用方法
diff --git a/js/functions/checkExistingGroup.js b/js/functions/checkExistingGroup.js
index 30bcc6d..10a1c16 100644
--- a/js/functions/checkExistingGroup.js
+++ b/js/functions/checkExistingGroup.js
@@ -5,6 +5,10 @@ import { util } from '@aws-appsync/utils';
 
 export function request(ctx) {
   const { hostId, domain } = ctx.args;
+  const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
+  const ttlSeconds = +(ctx.env.MESH_HOST_HEARTBEAT_TTL_SECONDS || '150');
+  const threshold = nowEpoch - ttlSeconds;
+  const nowISO = util.time.nowISO8601();
 
   // 既存グループの検索
   return {
@@ -17,9 +21,11 @@ export function request(ctx) {
       })
     },
     filter: {
-      expression: 'hostId = :hostId',
+      expression: 'hostId = :hostId AND heartbeatAt > :threshold AND expiresAt > :now',
       expressionValues: util.dynamodb.toMapValues({
-        ':hostId': hostId
+        ':hostId': hostId,
+        ':threshold': threshold,
+        ':now': nowISO
       })
     }
   };
diff --git a/js/functions/checkGroupExists.js b/js/functions/checkGroupExists.js
index 9890ef6..ba63b97 100644
--- a/js/functions/checkGroupExists.js
+++ b/js/functions/checkGroupExists.js
@@ -19,7 +19,8 @@ export function request(ctx) {
 export function response(ctx) {
   const { groupId, domain } = ctx.args;
   const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
-  const heartbeatThreshold = nowEpoch - 60; // heartbeat閾値: 60秒
+  const ttlSeconds = +(ctx.env.MESH_HOST_HEARTBEAT_TTL_SECONDS || '150');
+  const heartbeatThreshold = nowEpoch - ttlSeconds;
 
   // グループが存在しない
   if (!ctx.result) {
diff --git a/js/functions/createGroupIfNotExists.js b/js/functions/createGroupIfNotExists.js
index 20aa21a..4a011ff 100644
--- a/js/functions/createGroupIfNotExists.js
+++ b/js/functions/createGroupIfNotExists.js
@@ -24,7 +24,7 @@ export function request(ctx) {
   }
 
   // maxConnectionTimeSeconds のバリデーションと決定
-  const envMaxSeconds = +(ctx.env.MESH_MAX_CONNECTION_TIME_SECONDS || '3000');
+  const envMaxSeconds = +(ctx.env.MESH_MAX_CONNECTION_TIME_SECONDS || '1500');
   let actualMaxSeconds = envMaxSeconds;
 
   if (maxConnectionTimeSeconds !== undefined && maxConnectionTimeSeconds !== null) {
@@ -46,7 +46,8 @@ export function request(ctx) {
   const now = util.time.nowISO8601();
   const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
   const expiresAt = util.time.epochMilliSecondsToISO8601(util.time.nowEpochMilliSeconds() + actualMaxSeconds * 1000);
-  const ttl = nowEpoch + 60; // 1分間
+  const ttlSeconds = +(ctx.env.MESH_HOST_HEARTBEAT_TTL_SECONDS || '150');
+  const ttl = nowEpoch + ttlSeconds;
 
   return {
     operation: 'PutItem',
diff --git a/js/functions/findNodeMetadata.js b/js/functions/findNodeMetadata.js
index e158095..eaafe38 100644
--- a/js/functions/findNodeMetadata.js
+++ b/js/functions/findNodeMetadata.js
@@ -20,11 +20,14 @@ export function response(ctx) {
     util.error(ctx.error.message, ctx.error.type);
   }
 
-  if (!ctx.result) {
+  const result = ctx.result;
+  const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
+
+  if (!result || (result.ttl && result.ttl <= nowEpoch)) {
     return null;
   }
 
   // stashに保存して次のFunctionへ
-  ctx.stash.nodeMetadata = ctx.result;
-  return ctx.result;
+  ctx.stash.nodeMetadata = result;
+  return result;
 }
diff --git a/js/functions/renewHeartbeatFunction.js b/js/functions/renewHeartbeatFunction.js
index ddc73a7..5705cb4 100644
--- a/js/functions/renewHeartbeatFunction.js
+++ b/js/functions/renewHeartbeatFunction.js
@@ -48,6 +48,6 @@ export function response(ctx) {
     groupId: groupId,
     domain: domain,
     expiresAt: group.expiresAt,
-    heartbeatIntervalSeconds: +(ctx.env.MESH_HOST_HEARTBEAT_INTERVAL_SECONDS || '30')
+    heartbeatIntervalSeconds: +(ctx.env.MESH_HOST_HEARTBEAT_INTERVAL_SECONDS || '60')
   };
 }
diff --git a/js/resolvers/Mutation.createGroup.js b/js/resolvers/Mutation.createGroup.js
index dd5e749..24d0dac 100644
--- a/js/resolvers/Mutation.createGroup.js
+++ b/js/resolvers/Mutation.createGroup.js
@@ -12,7 +12,7 @@ export function request(ctx) {
   }
 
   // maxConnectionTimeSeconds のバリデーションと決定
-  const envMaxSeconds = +(ctx.env.MESH_MAX_CONNECTION_TIME_SECONDS || '3000');
+  const envMaxSeconds = +(ctx.env.MESH_MAX_CONNECTION_TIME_SECONDS || '1500');
   let actualMaxSeconds = envMaxSeconds;
 
   if (maxConnectionTimeSeconds !== undefined && maxConnectionTimeSeconds !== null) {
@@ -34,7 +34,8 @@ export function request(ctx) {
   const now = util.time.nowISO8601();
   const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
   const expiresAt = util.time.epochMilliSecondsToISO8601(util.time.nowEpochMilliSeconds() + actualMaxSeconds * 1000);
-  const ttl = nowEpoch + 60; // 1分間
+  const ttlSeconds = +(ctx.env.MESH_HOST_HEARTBEAT_TTL_SECONDS || '150');
+  const ttl = nowEpoch + ttlSeconds;
 
   return {
     operation: 'PutItem',
diff --git a/js/resolvers/Mutation.reportDataByNode.js b/js/resolvers/Mutation.reportDataByNode.js
index 3ed3bf8..9dd7d10 100644
--- a/js/resolvers/Mutation.reportDataByNode.js
+++ b/js/resolvers/Mutation.reportDataByNode.js
@@ -13,6 +13,10 @@ export function request(ctx) {
     value: item.value
   }));
 
+  const ttlSeconds = +(ctx.env.MESH_MEMBER_HEARTBEAT_TTL_SECONDS || '600');
+  const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
+  const ttl = nowEpoch + ttlSeconds;
+
   return {
     operation: 'PutItem',
     key: util.dynamodb.toMapValues({
@@ -25,6 +29,7 @@ export function request(ctx) {
       domain: domain,
       data: sensorDataList,
       timestamp: now,
+      ttl: ttl,
       // GSI用属性
       gsi_pk: `NODE#${nodeId}`,
       gsi_sk: 'STATUS'
diff --git a/js/resolvers/Query.listGroupStatuses.js b/js/resolvers/Query.listGroupStatuses.js
index 9411f5b..24eedec 100644
--- a/js/resolvers/Query.listGroupStatuses.js
+++ b/js/resolvers/Query.listGroupStatuses.js
@@ -10,6 +10,7 @@ export function request(ctx) {
   if (!domain || !groupId) {
     util.error('groupId and domain are required', 'ValidationError');
   }
+  const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
 
   // DynamoDB Query: DOMAIN#${domain} 配下の GROUP#${groupId}#NODE#*#STATUS を取得
   return {
@@ -20,6 +21,15 @@ export function request(ctx) {
         ':pk': `DOMAIN#${domain}`,
         ':sk_prefix': `GROUP#${groupId}#NODE#`
       })
+    },
+    filter: {
+      expression: 'attribute_not_exists(#ttl) OR #ttl > :now',
+      expressionNames: {
+        '#ttl': 'ttl'
+      },
+      expressionValues: util.dynamodb.toMapValues({
+        ':now': nowEpoch
+      })
     }
   };
 }
diff --git a/js/resolvers/Query.listGroupsByDomain.js b/js/resolvers/Query.listGroupsByDomain.js
index c72ee91..a48f5e0 100644
--- a/js/resolvers/Query.listGroupsByDomain.js
+++ b/js/resolvers/Query.listGroupsByDomain.js
@@ -6,7 +6,8 @@ import { util } from '@aws-appsync/utils';
 export function request(ctx) {
   const { domain } = ctx.args;
   const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
-  const threshold = nowEpoch - 60; // 1分前
+  const ttlSeconds = +(ctx.env.MESH_HOST_HEARTBEAT_TTL_SECONDS || '150');
+  const threshold = nowEpoch - ttlSeconds;
 
   return {
     operation: 'Query',
diff --git a/js/resolvers/Query.listNodesInGroup.js b/js/resolvers/Query.listNodesInGroup.js
index bb7cb4f..16fd55f 100644
--- a/js/resolvers/Query.listNodesInGroup.js
+++ b/js/resolvers/Query.listNodesInGroup.js
@@ -5,6 +5,7 @@ import { util } from '@aws-appsync/utils';
 
 export function request(ctx) {
   const { groupId, domain } = ctx.args;
+  const nowEpoch = Math.floor(util.time.nowEpochMilliSeconds() / 1000);
 
   return {
     operation: 'Query',
@@ -14,6 +15,15 @@ export function request(ctx) {
         ':pk': `DOMAIN#${domain}`,
         ':sk_prefix': `GROUP#${groupId}#NODE#`
       })
+    },
+    filter: {
+      expression: 'attribute_not_exists(#ttl) OR #ttl > :now',
+      expressionNames: {
+        '#ttl': 'ttl'
+      },
+      expressionValues: util.dynamodb.toMapValues({
+        ':now': nowEpoch
+      })
     }
   };
 }
diff --git a/lib/mesh-v2-stack.ts b/lib/mesh-v2-stack.ts
index 3fa5c48..8662d4f 100644
--- a/lib/mesh-v2-stack.ts
+++ b/lib/mesh-v2-stack.ts
@@ -71,7 +71,7 @@ export class MeshV2Stack extends cdk.Stack {
     });
 
     // Environment variables defaults based on stage
-    const defaultMaxConnTimeSeconds = stage === 'prod' ? '3000' : '600';
+    const defaultMaxConnTimeSeconds = stage === 'prod' ? '1500' : '300';
 
     // AppSync GraphQL API for Mesh v2
     this.api = new appsync.GraphqlApi(this, 'MeshV2Api', {
@@ -87,7 +87,7 @@ export class MeshV2Stack extends cdk.Stack {
       },
       environmentVariables: {
         TABLE_NAME: this.table.tableName,
-        MESH_HOST_HEARTBEAT_INTERVAL_SECONDS: process.env.MESH_HOST_HEARTBEAT_INTERVAL_SECONDS || '30',
+        MESH_HOST_HEARTBEAT_INTERVAL_SECONDS: process.env.MESH_HOST_HEARTBEAT_INTERVAL_SECONDS || '60',
         MESH_HOST_HEARTBEAT_TTL_SECONDS: process.env.MESH_HOST_HEARTBEAT_TTL_SECONDS || '150',
         MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS: process.env.MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS || '120',
         MESH_MEMBER_HEARTBEAT_TTL_SECONDS: process.env.MESH_MEMBER_HEARTBEAT_TTL_SECONDS || '600',
@@ -367,7 +367,7 @@ export class MeshV2Stack extends cdk.Stack {
         LC_ALL: 'en_US.UTF-8',
         DYNAMODB_TABLE_NAME: this.table.tableName,
         MESH_SECRET_KEY: process.env.MESH_SECRET_KEY || 'default-secret-key',
-        MESH_HOST_HEARTBEAT_INTERVAL_SECONDS: process.env.MESH_HOST_HEARTBEAT_INTERVAL_SECONDS || '30',
+        MESH_HOST_HEARTBEAT_INTERVAL_SECONDS: process.env.MESH_HOST_HEARTBEAT_INTERVAL_SECONDS || '60',
         MESH_HOST_HEARTBEAT_TTL_SECONDS: process.env.MESH_HOST_HEARTBEAT_TTL_SECONDS || '150',
         MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS: process.env.MESH_MEMBER_HEARTBEAT_INTERVAL_SECONDS || '120',
         MESH_MEMBER_HEARTBEAT_TTL_SECONDS: process.env.MESH_MEMBER_HEARTBEAT_TTL_SECONDS || '600',