A system configured to facilitate wakefulness in a subject during a sleep session, the system comprising: one or more sensory stimulators configured to provide electric, magnetic, and/or sensory stimulation to the subject during the sleep session; one or more sensors configured to generate output signals conveying information related to brain activity, activity of the central nervous system, and/or activity of the peripheral nervous system of the subject; and one or more hardware processors configured by machine readable instructions to: receive a target wake-up moment for the subject; and determine one or more activity parameters of the subject during the sleep session based on the output signals, characterized in that the one or more hardware processors are further configured by machine readable instructions to: determine a predetermined amount of time for the demographic of the subject, based on a recommended duration of deep sleep for demographically matched subjects; determine whether the one or more activity parameters indicate the subject is in deep sleep said predetermined amount of time before the target wake-up moment; and responsive to the one or more activity parameters indicating the subject is in deep sleep said predetermined amount of time before the target wake-up moment, cause the one or more sensory stimulators to control a frequency and/or an intensity of the stimulation to guide the one or more activity parameters of the subject and facilitate a transition from deep sleep to light sleep before the target wake-up moment such that the subject wakes from sleep naturally at or near the target wake-up moment. one or more sensory stimulators configured to provide electric, magnetic, and/or sensory stimulation to the subject during the sleep session; one or more sensors configured to generate output signals conveying information related to brain activity, activity of the central nervous system, and/or activity of the peripheral nervous system of the subject; and one or more hardware processors configured by machine readable instructions to: receive a target wake-up moment for the subject; and determine one or more activity parameters of the subject during the sleep session based on the output signals, characterized in that the one or more hardware processors are further configured by machine readable instructions to: determine a predetermined amount of time for the demographic of the subject, based on a recommended duration of deep sleep for demographically matched subjects; determine whether the one or more activity parameters indicate the subject is in deep sleep said predetermined amount of time before the target wake-up moment; and responsive to the one or more activity parameters indicating the subject is in deep sleep said predetermined amount of time before the target wake-up moment, cause the one or more sensory stimulators to control a frequency and/or an intensity of the stimulation to guide the one or more activity parameters of the subject and facilitate a transition from deep sleep to light sleep before the target wake-up moment such that the subject wakes from sleep naturally at or near the target wake-up moment. receive a target wake-up moment for the subject; and determine one or more activity parameters of the subject during the sleep session based on the output signals, characterized in that the one or more hardware processors are further configured by machine readable instructions to: determine a predetermined amount of time for the demographic of the subject, based on a recommended duration of deep sleep for demographically matched subjects; determine whether the one or more activity parameters indicate the subject is in deep sleep said predetermined amount of time before the target wake-up moment; and responsive to the one or more activity parameters indicating the subject is in deep sleep said predetermined amount of time before the target wake-up moment, cause the one or more sensory stimulators to control a frequency and/or an intensity of the stimulation to guide the one or more activity parameters of the subject and facilitate a transition from deep sleep to light sleep before the target wake-up moment such that the subject wakes from sleep naturally at or near the target wake-up moment. determine a predetermined amount of time for the demographic of the subject, based on a recommended duration of deep sleep for demographically matched subjects; determine whether the one or more activity parameters indicate the subject is in deep sleep said predetermined amount of time before the target wake-up moment; and responsive to the one or more activity parameters indicating the subject is in deep sleep said predetermined amount of time before the target wake-up moment, cause the one or more sensory stimulators to control a frequency and/or an intensity of the stimulation to guide the one or more activity parameters of the subject and facilitate a transition from deep sleep to light sleep before the target wake-up moment such that the subject wakes from sleep naturally at or near the target wake-up moment.