Ramadan Sleep Schedule: How Fasting Impacts Nighttime Rest

Fasting during Ramadan significantly alters daily routines, including sleep patterns. With meals and prayers scheduled outside daylight hours, many experience disruptions in rest, affecting energy levels, cognitive function, and overall well-being.

Understanding how fasting impacts sleep can help individuals make adjustments to maintain rest quality.

Circadian Rhythm Adjustments During Fasting Hours

The body’s internal clock, or circadian rhythm, is regulated by light exposure and meal timing. During Ramadan, restricted food intake to pre-dawn (Suhoor) and post-sunset (Iftar) hours shifts this biological system. Normally, metabolic processes such as glucose regulation and hormone secretion follow a 24-hour cycle, but fasting alters these rhythms, affecting sleep-wake patterns. Research in Chronobiology International shows that delayed food intake can push the body’s internal clock later into the night.

Melatonin, the hormone responsible for sleep initiation, is sensitive to meal timing. Under normal conditions, melatonin secretion begins in the evening, promoting drowsiness. However, studies show late-night eating suppresses melatonin release, delaying sleep onset. Research in The Journal of Clinical Endocrinology & Metabolism found that consuming meals close to bedtime shifts melatonin secretion later, making it harder to fall asleep after Iftar. Waking early for Suhoor further misaligns the body’s natural sleep drive.

Core body temperature, another sleep regulator, fluctuates in response to fasting. Typically, body temperature drops in the evening, signaling the body to prepare for sleep. However, food intake raises metabolic activity and temperature, interfering with this process. A study in Sleep Medicine Reviews suggests late-night meals delay the nocturnal drop in core temperature, making it harder to transition into deep sleep. Digestion also activates the sympathetic nervous system, increasing alertness when the body should be winding down.

Hormonal Shifts Linked to Late-Night Eating

The timing of meals during Ramadan significantly impacts hormonal balance. Insulin, ghrelin, leptin, and cortisol—key regulators of metabolism and appetite—fluctuate in response to nighttime eating. Research in The American Journal of Clinical Nutrition highlights that consuming food at night can lead to insulin resistance over time, as glucose processing is less efficient in the evening. This can contribute to post-meal hyperglycemia, prolonging wakefulness and delaying sleep.

Ghrelin, the “hunger hormone,” typically rises before meals and decreases after eating. Fasting disrupts this cycle, leading to elevated ghrelin levels in the evening. A study in Obesity Reviews found that increased ghrelin at night heightens alertness, making it harder to fall asleep, especially after Iftar. Meanwhile, leptin, responsible for satiety, experiences a delayed peak. Normally, leptin rises at night to suppress hunger and support sleep, but late-night eating disrupts this pattern, increasing nocturnal wakefulness.

Cortisol, which regulates stress and the sleep-wake cycle, also shifts due to nighttime meals. Typically, cortisol peaks in the morning and declines throughout the day. However, late-night eating triggers prolonged cortisol elevations, as digestion stimulates the hypothalamic-pituitary-adrenal (HPA) axis. A study in Psychoneuroendocrinology found that individuals consuming high-calorie meals at night exhibited prolonged cortisol elevation, which suppresses melatonin and delays sleep onset.

Sleep Architecture and Fragmentation

Sleep structure changes significantly during Ramadan due to altered nocturnal routines. Sleep architecture, consisting of light sleep, deep sleep, and rapid eye movement (REM) sleep, is affected by duration and continuity. When sleep is shortened or interrupted, the proportion of restorative deep and REM sleep decreases. Polysomnography studies show that fasting individuals experience a reduction in slow-wave sleep, essential for physical recovery and immune function. Irregular schedules to accommodate nighttime meals and pre-dawn prayers fragment the sleep cycle.

Frequent awakenings further disrupt sleep, preventing the body from progressing smoothly through sleep stages. Those who sleep in multiple segments—such as a short rest after Iftar and another after Suhoor—struggle to achieve prolonged deep sleep. Research in Sleep Medicine shows fragmented sleep increases sleep inertia, or grogginess upon waking, due to incomplete sleep cycles. This grogginess worsens as the body attempts to compensate for lost REM sleep, which is crucial for cognitive processing and emotional regulation.

Daytime Sleepiness and Cognitive Function

Disruptions in sleep during Ramadan often lead to increased daytime drowsiness, affecting mental sharpness and cognitive efficiency. With sleep duration frequently shortened and fragmented, the body struggles to maintain alertness throughout the day. This decline is particularly noticeable in tasks requiring sustained attention and complex decision-making. Research in Neuroscience & Biobehavioral Reviews indicates that even one to two hours of lost sleep per night significantly reduces reaction times and working memory, affecting activities such as driving, studying, and work performance.

Beyond fatigue, insufficient sleep impairs executive function, which governs reasoning and impulse control. Studies on time-restricted eating show that individuals with disrupted sleep exhibit inconsistent cognitive performance, leading to lapses in judgment and difficulty adapting to new information. Electroencephalogram (EEG) studies reveal that sleep deprivation alters brainwave activity, particularly in the prefrontal cortex, a region crucial for decision-making and emotional regulation.