In contrast, patients with depression who had >4 ultradian sleep cycles (n=52) displayed sleep alterations consistent with REMS disinhibition, including shortened REM latency and increases in REMS ...

However, there is evidence that daily activity is also influenced by rhythms much shorter than 24 hours, which are known as ultradian rhythms and follow a four-hour cycle. Most prominently ...

While circadian rhythms such as the sleep-wake cycle follow a 24-hour cycle, ultradian rhythms are biological rhythms that recur more frequently than once every 24 hours. They govern various ...

Why? It’s the ultradian rhythm, a cycle that’s present in both our sleeping and waking lives. As Tony Schwartz has reported, this was first discovered by Nathan Kleitman, a groundbreaking ...

The ultradian rhythm determines productivity based on the body’s alternating rest-activity cycle, which lasts 80–120 minutes, approximately. Sway to a different kind of rhythm, the ultradian ...

This intriguing pattern reflects 12-hour biological rhythms, also called ultradian or circasemidian cycles. These rhythms are well known in marine animals that respond to tidal cycles. However ...

Within the larger circadian cycle, our brain operates on ultradian rhythms, which last about 90 minutes. After this period of intense focus, our brain needs a 15–20 minute recovery phase.

circadian cycle. Although not widely recognized, the actual pattern of hormone secretion is highly pulsatile (ultradian), with a periodicity of approximately 1 h; this pattern is also maintained ...

Source Reference: Schulze-Bonhage A “From moon to earth—ultradian cycles in brain excitability” Lancet Neurol 2018; DOI: 10.1016/S1474-4422(18)30337-5.