diff --git a/app/routes.py b/app/routes.py
index a9b4d98..a5204b0 100644
--- a/app/routes.py
+++ b/app/routes.py
@@ -2,6 +2,7 @@ import csv
 from io import StringIO
 import io
 from flask import Blueprint, Response, make_response, render_template, redirect, request, send_file, url_for, flash
+from sqlalchemy import func
 from werkzeug.security import generate_password_hash, check_password_hash
 from werkzeug.http import http_date
 from app.models import Profile, Reading, db, User
@@ -56,9 +57,29 @@ def landing():
 @main.route('/dashboard', methods=['GET', 'POST'])
 @login_required
 def dashboard():
-    # Default values
+    # Initialize start_date and end_date
     start_date = None
     end_date = None
+    
+    # Retrieve the first and last timestamps in a single query
+    first_last_readings = (
+        db.session.query(
+            func.min(Reading.timestamp).label('first'),
+            func.max(Reading.timestamp).label('last')
+        )
+        .filter(Reading.user_id == current_user.id)
+        .first()
+    )
+
+    # Extract the first and last timestamps
+    first_reading_timestamp = first_last_readings.first
+    last_reading_timestamp = first_last_readings.last
+
+    # Default to first and last reading dates if not provided
+    if not start_date and first_reading_timestamp:
+        start_date = first_reading_timestamp.strftime('%Y-%m-%d')
+    if not end_date and last_reading_timestamp:
+        end_date = last_reading_timestamp.strftime('%Y-%m-%d')
 
     # Default to all readings
     readings_query = Reading.query.filter_by(user_id=current_user.id)
diff --git a/app/templates/dashboard.html b/app/templates/dashboard.html
index 2234459..ba0457d 100644
--- a/app/templates/dashboard.html
+++ b/app/templates/dashboard.html
@@ -125,7 +125,7 @@
         </div>
     </div>
 
-    <div x-data="{ open: {{ 'true' if start_date or end_date else 'false' }} }"
+    <div x-data="{ open: {{ 'true' if request.method == 'POST' else 'false' }} }"
         class="p-4 bg-white rounded-lg shadow-md">
         <!-- Collapsible Header -->
         <div class="flex justify-between items-center">