At some point, many of us have been labeled a “sleepyhead” for yawning or dozing off at an inconvenient time or place. Often, this drowsiness is just the result of a late-night gathering, an all-night study session, or a long, intensive work meeting. Catching up on sleep after a hectic day is fairly harmless, but when daytime drowsiness becomes a routine, it may signal an underlying issue.
In today’s fast-paced world, taking time to rest can seem like a luxury. However, sleep is just as essential to health as a balanced diet and regular exercise. Quality sleep enhances brain performance, stabilizes mood, and promotes physical well-being. Your daytime alertness and energy levels depend partly on the restorative work your body does during sleep. In children and teens, sleep is also crucial for healthy growth and development. Insufficient sleep can increase the risk of chronic health problems, including heart disease, stroke, obesity, and dementia, and can impair your cognitive abilities, emotional health, and social interactions.
Sleep helps your brain form and retain pathways for learning and memory while allowing neurons to communicate efficiently. Getting adequate rest also supports a healthy weight, heart function, metabolism, and reduces the risk of chronic conditions such as type 2 diabetes and high blood pressure. It even helps alleviate stress and improve mood.
However, frequent daytime sleepiness can be a red flag, potentially indicating cognitive decline or other health issues. Here are some common causes of excessive daytime sleepiness:
- Sleep Deprivation: Insufficient sleep due to work shifts, family responsibilities, or lifestyle factors can lead to excessive drowsiness.
- Sleep Disorders: Conditions like obstructive sleep apnea and narcolepsy often cause persistent daytime sleepiness.
- Medications: Certain medications, including tranquilizers, antihistamines, and some painkillers, may cause drowsiness as a side effect.
- Diet: A poor diet or irregular eating habits can contribute to fatigue and sluggishness.
- Circadian Rhythm: Our natural circadian rhythm typically includes a period of drowsiness in the afternoon, which can make you feel sleepy during the day.
- Vitamin D Deficiency: Low vitamin D levels, especially in older adults, have been linked to increased daytime sleepiness.
Other Medical Conditions
Conditions such as diabetes, chronic pain, hypothyroidism, and imbalances in blood sodium levels can also cause daytime drowsiness.
Hypersomnia
Hypersomnia is a condition marked by difficulty staying awake and alert during the day, even after adequate nighttime sleep. It can impair work and social interactions, reduce quality of life, and raise the risk of accidents. While the causes of hypersomnia are not fully understood, researchers believe neurotransmitters in the brain and cerebrospinal fluid, such as dopamine, histamine, and serotonin, may play a role. Genetic factors are also under investigation, as hypersomnia often appears in families.
Diagnosis and Treatment
Hypersomnia is diagnosed using tests such as polysomnography, an overnight sleep study that tracks brain waves, breathing, heart rhythms, and muscle movements during sleep stages. Another test, the Multiple Sleep Latency Test, measures the tendency to fall asleep during brief, scheduled naps throughout the day. Treatments for hypersomnia include medication and lifestyle changes such as regular sleep schedules, a sleep-friendly environment, and avoiding caffeine or exercise before bed.
Dementia Risk
Older adults experiencing excessive daytime sleepiness or lack of motivation may have a higher likelihood of developing motoric cognitive risk syndrome (MCR), a condition associated with slower walking speed and reported memory issues. MCR often precedes symptoms of dementia. While the link between daytime sleepiness and MCR is not causal, studies suggest that sleep issues may raise the risk of cognitive decline.
