Massive multiple-input multiple-output (Massive MIMO) is regarded as a potential technique to increase spectral efficiency (SE) and energy efficiency (EE) For the next generation of wireless networks. Meanwhile, EE is becoming an increasingly important concern for communications operators in order to not only maintain profitability but also reduce the overall negative impact on the environment. In this paper, a new advanced sleep mode (ASM) technique dedicated to massive MIMO network is proposed. In proposed ASM based massive MIMO, a certain number of antennas are switched ON/OFF according to the traffic loads aiming to improve the EE performance. Simulation results show that significant energy efficiency gains can be achieved by the proposed ASM based massive MIMO, especially in low load conditions. At optimal SE, the proposed approach improves the network EE by up to 3%, 24% and 54.6% for high, medium, and low traffic load factors, respectively, when compared to traditional MIMO operation without sleep mode.