Circadian rhythm refers to a fundamental 24-hour physiological cycle, which is essential for various molecular and behavioral processes. It mainly aids in regulating sleep patterns. The timing of circadian rhythms varies across individuals and is influenced by both environmental and genetic factors. People with earlier rhythms tend to rise early in the morning and feel sleepy earlier in the night and are referred to as a “morning/ early riser.” Many scientific studies have shown that morning people are more focused, persistent, agreeable, plan for their future better, less likely to smoke and drink or get depressed. Individuals with certain genetic variations have a higher tendency to be an early riser and may exhibit characteristics like being early risers, more active during morning hours, happier, focused, and more productive during the day.

Circadian rhythm refers to a fundamental 24-hour physiological cycle, which is essential for various molecular and behavioral processes. It mainly aids in regulating sleep patterns. The timing of circadian rhythms varies across individuals and is influenced by both environmental and genetic factors. People with later rhythms tend to have late-night sleeping and late rising times and are often referred to as an “evening” or as a “night owl” person. Night owls enjoy a burst of strength during the night. Individuals with certain genetic variations have a higher tendency to be a night owl. They may exhibit characteristics like late risers, more active during evening hours, creative, adventurous, and more productive during the night.

Sleep duration refers to the total amount of sleep obtained either during the nighttime sleep event or across the 24-hr period. Sleep duration is associated with cardiovascular diseases, type 2 diabetes, depression, automobile and workplace accidents, learning and memory problems, and prospective mortality. Certain risk factors such as smoking, alcohol consumption, and physical inactivity may lead to shorter sleep duration. As sleep is an important factor associated with many processes in the body like balancing the immune system, cellular cleanup of the nervous system, and regulation of hormone levels, people need to optimize their sleep duration to overcome chronic health issues and achieve the best cognitive function and health.

Snoring is the loud or harsh sound from the nose or mouth that occurs when breathing is partially obstructed. The sound is produced when the soft palate and other soft tissues (such as uvula, tonsils, nasal turbinates, and others) in the upper airway vibrate. Snoring is caused due to various factors such as genetic predisposition, throat weakness, obesity, mispositioned jaw, obstructive sleep apnea, sleep deprivation, alcohol consumption, and mouth breathing. Research studies have shown that various genes are associated with snoring are involved in respiratory, cognitive, psychiatric, and cardiometabolic disorders.

Insomnia (also known as Sleeplessness) is a common sleep disorder characterized by the inability to fall asleep or stay asleep at night, resulting in tired or unrefreshing sleep. These symptoms can be caused by variations in biological, psychological, and social factors, resulting in a reduced amount of sleep. Insomnia affects women and older people more than men and younger ones. Recent studies have shown that genetic factors play an important role in influencing the insomnia etiology by regulating the sleep-related genes.

Caffeine is a central nervous system stimulant, which is widely used for its psychoactive effects. It is commonly used to alleviate behavioral, cognitive, and emotional deficits caused by sleep deprivation. Regardless of its beneficial effects, caffeine may have adverse sleep-related consequences that might lead to sleep disruption and insomnia symptoms. Research studies have documented that individuals with caffeine-induced insomnia show poor sleep quality, higher latency to fall asleep, and a higher proportion of psychiatric diagnoses and daily use of hypnotic drugs.

Obstructive Sleep Apnea (OSA) is a common, serious, and potentially life-threatening sleep disorder. It is characterized by frequent episodes of partial or complete upper airway obstruction during sleep, resulting in intermittent hypoxemia and arousal. People with OSA are at increased risk for developing cardiovascular disease, stroke, type 2 diabetes, and other disorders that influence significant morbidity and premature mortality.

Excessive Daytime Sleepiness (also known as Hypersomnia) refers to an inability to stay awake and alert during the normal waking hours that results in unexpected lapses of sleep or drowsiness. It is a serious symptom, and if untreated, it can result in obstructive sleep apnea, cognitive impairment, compromised quality of life, and reduced productivity. Longitudinal studies have shown that excessive daytime sleepiness is associated with an increased risk of developing coronary heart disease and stroke. However, the risk can be managed by adopting better sleep habits.

Narcolepsy is a sleep disorder that is characterized by five symptoms - excessive daytime sleepiness, cataplexy (sudden muscle weakness that occurs without any ‘warning’), sleep paralysis (a state of awareness with an inability to speak or move - usually occurs during waking up or falling asleep), hypnagogic hallucinations (vivid dreamlike experiences), and disturbed nocturnal sleep. It affects approximately 1 in 2000 individuals and usually appears during childhood or early puberty. Studies have documented that certain variations in genes involved in regulating immune function are associated with the risk of developing narcolepsy.

Sleep efficiency refers to the percentage of time a person sleeps to the amount of time a person spends in bed. It is calculated by the ratio of the total time spent asleep (TST) in a night compared to the total amount of time spent in bed. An efficient sleep leads to a deeper sleep of better quality with lesser disturbances. This can help you feel energized when you wake up. On the other hand, inefficient sleep may lead to uneasiness and fatigue.

Sleep latency (also known as sleep onset latency) refers to the amount of time it takes for a person to fall asleep. Usually, normal sleep latency is 5-15 minutes. If sleep latency is less than five minutes, it may suggest some level of excessive sleepiness, and if it is greater than 15 minutes, it may be due to sleep initiation issues.

Restless Leg Syndrome (also known as Willis-Ekbom Disease) is a neurologic and sleep-related movement disorder characterized by an irresistible urge to move in the legs, which typically occurs or worsens at rest. People with restless leg syndrome may experience abnormal, uncomfortable sensations (paresthesias or dysesthesias) that are often likened to cramping, crawling, burning, aching, itching, or prickling deep within the affected areas. Certain genetic variants in MEIS1, PTPRD, BTBD9, MAP2K5, and other genes might influence the risk of developing restless legs syndrome. It has been shown that a family member with this condition increases the risk for another member by 60%.

Sleep Bruxism (also known as Teeth Grinding) is defined as the repetitive jaw muscle activity during sleep, characterized by an unconscious act of grinding or clenching one’s teeth tightly together. However, over time, it could lead to teeth damage, oral health conditions, facial muscle pain, sleep disturbances, difficulty while speaking, or eating. Sleep bruxism may be accelerated by stress, alcohol consumption, anxiety, cigarette smoking, upper airway resistance, and caffeine consumption. Certain genetic variants in MMP9, HTR2A, DRD3, COMT, and other genes might influence the risk of developing bruxism.

Sleep fragmentation is a sleep disorder characterized by repeated, short sleep interruptions during the night, leading to excessive tiredness during the day. People with fragmented sleep tend to fall asleep quickly but wake up multiple times during midnight for short periods. The other symptoms of fragmented sleep include morning headaches, daytime sleepiness, difficulty in concentrating, and memory lapses. Research studies have documented a greater impact on physical and emotional health when sleep quality and quantity are poor. Certain genetic variants in HLA-DQB1, CRY1, and other genes might influence the risk of having fragmented sleep.