Spontaneous intrapersonal synchronization is the spontaneous synchronization of periodic behaviors within an individual. It is less investigated than spontaneous interpersonal synchronization, the synchronization of periodic behaviors that occurs spontaneously between individuals integrated into a single system through coupling, caused by the exchange of sensory feedback between them. It was therefore hypothesized that periodic behaviors produced by an individual, a single system by default, would spontaneously be more synchronous through exchange of sensory feedback, coupling and integration within the individual, when the behaviors are produced simultaneously, compared to separately. Based on a postulate that explains spontaneous interpersonal synchronization as a strategy by the brain to conserve resources, and predicts individuals under high cognitive load to spontaneously synchronize their behaviors with others to conserve resources, it was hypothesized that spontaneous intrapersonal synchronization would increase under additional cognitive load. We tested our hypotheses through two experiments, each with a different pair of periodic tasks, and a different cognitive load task. In each experiment, we compared the phase coherence of two periodic tasks, tapping-walking or tapping-ticking, when produced by an individual simultaneously versus separately; we also compared the same when produced simultaneously with additional cognitive load versus without load. Here, ticking was a periodic task where the word “tick” was uttered repetitively. Counting backwards and visual pattern-matching were used as cognitive load tasks. Results showed that spontaneous intrapersonal synchronization between periodic tasks was higher when produced simultaneously, compared to separately, and the same was lower with additional cognitive load, compared to without load.