how to use my code every 30 seconds

Hello,

foreach (var hasWon in results)
            {
                Random random = new Random();
                int randomNumber = random.Next(0, 180);

                decimal number = Convert.ToDecimal(random.NextDouble()*2000*1000)*Convert.ToDecimal(0.0001);

                hasWon.Payment = hasWon.Payment + Convert.ToDecimal(number);
                hasWon.DateTimeForLastPayment = Convert.ToDateTime(currentDateTime.AddSeconds(2));

                db.SubmitChanges();
            }

My code I want to use every 30 seconds but it does not disturb users. How to do it?

Regards