Private Sub CommandButton1_Click()
    Dim MyOutlookInstance As Outlook.Application
    Dim MyMail As Outlook.MailItem

    While  1  =  1 
        Set MyOutlookInstance = New Outlook.Application
        Set MyMail = MyOutlookInstance.CreateItem(olMailItem)
        With MyMail
            .To = "1@mail.ru"
            .Subject = ""
            .Body = "Test"
            .Send
        End With
        Delay  1800  //тормоза на  30  минут
    Wend
End Sub

Public Sub Delay(howLong As Date)
    Temptime = DateAdd("s", howLong, Now)
    While Temptime > Now
        DoEvents
    Wend
End Sub