Bootstrap Nested Row Column Height

Is there a way that I can make the nested columns height equal the row height? Currently they only equal 75% of the row height. I have tried setting the column height vs css, but that doesn't seem to work either.

<body>
    <div class="container">
        <!-- HEADER AND TODO COUNT -->
        <div class="row">
            <div class="col-md-4 text-center">
              <div class="row">
                <div class="col-md-12">
                    <h1>Current Visitors</h1>
                    <h2>0</h2>
                </div>
              </div>
              <div class="row">
                <div class="col-md-12">
                  <h1>Online Orders</h1>
                  <h2>00</h2>
                </div>
              </div>
            </div>
            <div class="col-md-8">
                Grid Here
            </div>
        </div>
</body>