Brain fog, bad mood and memory woes? It could just be your sleep

“I feel so fresh this morning,” said a patient recently. “I got a good sleep last night. I can function much better now.” It is something many of us can relate to after a restful night, the mind feels clearer, the mood brighter, and the day just goes smoother. But can sleep actually make you smarter?

In today’s fast-paced life—especially in cities like Mumbai—sleep often takes a backseat. People spend hours commuting, work long shifts, and come home to a list of household responsibilities. Dinner is often late, and most people do not get to bed before midnight. For many, sleep is the first thing sacrificed.

Take the case of another patient, a young girl who came to clinic recently. She was once a bright student, but now complains of poor concentration, memory issues, daily headaches, and declining academic performance. Her sleep pattern? Bedtime at 2 or 3 a.m., thanks to hours spent on social media and YouTube. Sadly, this is not rare.
What happens to the brain during sleep?

During sleep your brain processes what it has learnt throughout the day. It helps improve your ability to concentrate, learn new things and hence improves the cognitive function. Here is how it benefits your brain:

Consolidation of memory: As we sleep, our brain organizes the thoughts, memories and filters out irrelevant ones, helping you to learn and remember better.

Removal of toxins: During sleep, the brain’s waste clearance system, called the glymphatic system, becomes active. It clears harmful substances such as beta-amyloid, a protein that causes Alzheimer’s disease.

Emotional balance: Sleep “resets” emotional circuits. Lack of it can lead to irritability, stress, anxiety and depression and poor decision making.

Enhanced problem solving and creativity: Think of sleep as your brain’s battery recharge. A well-rested mind is sharper, more creative, and better at tackling complex problems.

How much sleep do we really need?
Adults should aim for 7-8 hours of sleep per night. Infants and children need more. It’s not just the duration; it’s the quality that also matters. Sleeping late at night, waking up in the night multiple times will leave you feeling tired in the morning.

Sleep patterns also change as we age. Older adults often experience lighter sleep and more frequent awakenings. Studies have shown that maintaining healthy sleep in later life can protect against cognitive decline.

The link between poor sleep and cognitive decline
There is growing evidence that poor sleep is linked to cognitive disorders like Alzheimer’s and Parkinson’s disease. But it is not just a symptom—poor sleep may actually contribute to cognitive decline. Exact mechanism is not understood but several factors have been thought to play a role:

• Buildup of beta-amyloid: Sleep deprivation leads to accumulation of amyloid-beta plaques in the brain. This not only disrupts sleep further but also accelerates brain aging.
• Inflammation: Poor sleep causes increased inflammation in the brain, especially in the hippocampus which is the center for learning and memory.
• Imbalance of neurotransmitter substance: Poor sleep reduces levels of acetylcholine, a brain chemical essential for both memory and sleep regulation. This imbalance can worsen cognitive performance over time.

How can you improve your sleep hygiene?
Good sleep hygiene is the key for better health. Here are simple ways to improve your sleep quality:

• Exercise regularly: at least 30 minutes of daily exercise improves your sleep quality
• Limit daytime naps: Keep naps under 30 minutes to avoid insomnia.
• Get sunlight exposure: Natural light helps regularize your biological clock.
• Avoid stimulants and food before bedtime: Say no to caffeine, nicotine or alcohol before bedtime. Avoid eating heavy meals just before bedtime.
• Limit your screentime: Blue light from TV, laptop, mobile may decrease your sleep quality and duration. Shut off devices at least an hour before bedtime.
• Create a restful environment: A cool, dark, quiet bedroom with a comfortable bed helps signal your body it is time to sleep.
• Stick to a schedule: Go to bed and wake up at the same time every day—even on weekends.

Dr. Megha Sheth-Dhamne, Consultant Neurologist and Neuromuscular Specialist, P. D. Hinduja Hospital & Medical Research Centre, Mahim