Wireless sensor network (WSN) is a strapping combination of inexpensive, diminutive, computational and communication impelled sensor nodes which are powered by irreplaceable battery. So the lifetime of a sensor node is fixed. This lifetime can be increased only by using proper management of power consumption. Duty cycle based energy management scheme is very efficient medium access control (MAC) protocol of the WSN which effectively conserve energy of sensor nodes. In this paper, we propose a new management scheme for the duty cycle based MAC protocol to reduce the energy consumption by the sensor nodes as well as improve the network lifetime. In the proposed scheme, the total duty cycle is divided into two equal parts, one part is used for transmission of own data and another part is used for transmission/reception of neighbor node's data. If there is no data available for either own or neighbor nodes then it will go to the sleep mode during that part of duty cycle to save the energy consumption. The performance of the proposed protocol is evaluated by numerical simulations. From the simulation results it is confirmed that the proposed scheme provides lower energy consumption as well as higher lifetime than the existing scheme.